Antigenic variation. Medical search

Change in the surface ANTIGEN of a microorganism. There are two different types. One is a phenomenon, especially associated with INFLUENZA VIRUSES, where they undergo spontaneous variation both as slow antigenic drift and sudden emergence of new strains (antigenic shift). The second type is when certain PARASITES, especially trypanosomes, PLASMODIUM, and BORRELIA, survive the immune response of the host by changing the surface coat (antigen switching). (From Herbert et al., The Dictionary of Immunology, 4th ed)

Genotypic differences observed among individuals in a population.

Glycoproteins attached to the surface coat of the trypanosome. Many of these glycoproteins show amino acid sequence diversity expressed as antigenic variations. This continuous development of antigenically distinct variants in the course of infection ensures that some trypanosomes always survive the development of immune response to propagate the infection.

The functional hereditary units of protozoa.

A hemoflagellate subspecies of parasitic protozoa that causes nagana in domestic and game animals in Africa. It apparently does not infect humans. It is transmitted by bites of tsetse flies (Glossina).

A genus of flagellate protozoans found in the blood and lymph of vertebrates and invertebrates, both hosts being required to complete the life cycle.

Substances elaborated by bacteria that have antigenic activity.

Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.

Proteins found in any species of protozoan.

A species of protozoa that is a cause of bovine babesiosis. Ticks of the genera Boophilus, Rhipicephalus, and IXODES are the chief vectors.

Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.

Proteins that are structural components of bacterial fimbriae (FIMBRIAE, BACTERIAL) or sex pili (PILI, SEX).

A species of gram-negative, aerobic bacteria primarily found in purulent venereal discharges. It is the causative agent of GONORRHEA.

A genus of gram-negative, anaerobic, helical bacteria, various species of which produce RELAPSING FEVER in humans and other animals.

Infection with protozoa of the genus TRYPANOSOMA.

Sites on an antigen that interact with specific antibodies.

Substances elaborated by viruses that have antigenic activity.

The order of amino acids as they occur in a polypeptide chain. This is referred to as the primary structure of proteins. It is of fundamental importance in determining PROTEIN CONFORMATION.

Proteins isolated from the outer membrane of Gram-negative bacteria.

A species of protozoa that is the causal agent of falciparum malaria (MALARIA, FALCIPARUM). It is most prevalent in the tropics and subtropics.

Production of new arrangements of DNA by various mechanisms such as assortment and segregation, CROSSING OVER; GENE CONVERSION; GENETIC TRANSFORMATION; GENETIC CONJUGATION; GENETIC TRANSDUCTION; or mixed infection of viruses.

The relationship between an invertebrate and another organism (the host), one of which lives at the expense of the other. Traditionally excluded from definition of parasites are pathogenic BACTERIA; FUNGI; VIRUSES; and PLANTS; though they may live parasitically.

The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.

A species of parasitic EUKARYOTES that attaches itself to the intestinal mucosa and feeds on mucous secretions. The organism is roughly pear-shaped and motility is somewhat erratic, with a slow oscillation about the long axis.

A hemoflagellate subspecies of parasitic protozoa that causes Gambian or West African sleeping sickness in humans. The vector host is usually the tsetse fly (Glossina).

A multistage process that includes cloning, physical mapping, subcloning, determination of the DNA SEQUENCE, and information analysis.

Proteins found in any species of bacterium.

A disease endemic among people and animals in Central Africa. It is caused by various species of trypanosomes, particularly T. gambiense and T. rhodesiense. Its second host is the TSETSE FLY. Involvement of the central nervous system produces "African sleeping sickness." Nagana is a rapidly fatal trypanosomiasis of horses and other animals.

An infection of the SMALL INTESTINE caused by the flagellated protozoan GIARDIA LAMBLIA. It is spread via contaminated food and water and by direct person-to-person contact.

An acute infection characterized by recurrent episodes of PYREXIA alternating with asymptomatic intervals of apparent recovery. This condition is caused by SPIROCHETES of the genus BORRELIA. It is transmitted by the BITES of either the body louse (PEDICULUS humanus corporis), for which humans are the reservoir, or by soft ticks of the genus ORNITHODOROS, for which rodents and other animals are the principal reservoirs.

Methods used by pathogenic organisms to evade a host's immune system.

Antigens on surfaces of cells, including infectious or foreign cells or viruses. They are usually protein-containing groups on cell membranes or walls and may be isolated.

A genus of gram-negative bacteria whose organisms are obligate parasites of vertebrates. Species are transmitted by arthropod vectors with the host range limited to ruminants. Anaplasma marginale is the most pathogenic species and is the causative agent of severe bovine anaplasmosis.

The complete genetic complement contained in a set of CHROMOSOMES in a protozoan.

Ribonucleic acid in protozoa having regulatory and catalytic roles as well as involvement in protein synthesis.

Deoxyribonucleic acid that makes up the genetic material of protozoa.

Antibodies produced by a single clone of cells.

The relationships of groups of organisms as reflected by their genetic makeup.

Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.

A species of bacteria present in man and many kinds of animals and birds, often causing infertility and/or abortion.

The measurement of infection-blocking titer of ANTISERA by testing a series of dilutions for a given virus-antiserum interaction end-point, which is generally the dilution at which tissue cultures inoculated with the serum-virus mixtures demonstrate cytopathology (CPE) or the dilution at which 50% of test animals injected with serum-virus mixtures show infectivity (ID50) or die (LD50).

Process of determining and distinguishing species of bacteria or viruses based on antigens they share.

The restriction of a characteristic behavior, anatomical structure or physical system, such as immune response; metabolic response, or gene or gene variant to the members of one species. It refers to that property which differentiates one species from another but it is also used for phylogenetic levels higher or lower than the species.

The asymmetrical segregation of genes during replication which leads to the production of non-reciprocal recombinant strands and the apparent conversion of one allele into another. Thus, e.g., the meiotic products of an Aa individual may be AAAa or aaaA instead of AAaa, i.e., the A allele has been converted into the a allele or vice versa.

A genus of the family PICORNAVIRIDAE infecting mainly cloven-hoofed animals. They cause vesicular lesions and upper respiratory tract infections. FOOT AND MOUTH DISEASE VIRUS is the type species.

Deoxyribonucleic acid that makes up the genetic material of bacteria.

A set of genes descended by duplication and variation from some ancestral gene. Such genes may be clustered together on the same chromosome or dispersed on different chromosomes. Examples of multigene families include those that encode the hemoglobins, immunoglobulins, histocompatibility antigens, actins, tubulins, keratins, collagens, heat shock proteins, salivary glue proteins, chorion proteins, cuticle proteins, yolk proteins, and phaseolins, as well as histones, ribosomal RNA, and transfer RNA genes. The latter three are examples of reiterated genes, where hundreds of identical genes are present in a tandem array. (King & Stanfield, A Dictionary of Genetics, 4th ed)

Malaria caused by PLASMODIUM FALCIPARUM. This is the severest form of malaria and is associated with the highest levels of parasites in the blood. This disease is characterized by irregularly recurring febrile paroxysms that in extreme cases occur with acute cerebral, renal, or gastrointestinal manifestations.

Thin, hairlike appendages, 1 to 20 microns in length and often occurring in large numbers, present on the cells of gram-negative bacteria, particularly Enterobacteriaceae and Neisseria. Unlike flagella, they do not possess motility, but being protein (pilin) in nature, they possess antigenic and hemagglutinating properties. They are of medical importance because some fimbriae mediate the attachment of bacteria to cells via adhesins (ADHESINS, BACTERIAL). Bacterial fimbriae refer to common pili, to be distinguished from the preferred use of "pili", which is confined to sex pili (PILI, SEX).

A terminal section of a chromosome which has a specialized structure and which is involved in chromosomal replication and stability. Its length is believed to be a few hundred base pairs.

Serologic tests in which a known quantity of antigen is added to the serum prior to the addition of a red cell suspension. Reaction result is expressed as the smallest amount of antigen which causes complete inhibition of hemagglutination.

A genus of gram-negative, mostly facultatively anaerobic bacteria in the family MYCOPLASMATACEAE. The cells are bounded by a PLASMA MEMBRANE and lack a true CELL WALL. Its organisms are pathogens found on the MUCOUS MEMBRANES of humans, ANIMALS, and BIRDS.

Viral disease of horses caused by the equine infectious anemia virus (EIAV; INFECTIOUS ANEMIA VIRUS, EQUINE). It is characterized by intermittent fever, weakness, and anemia. Chronic infection consists of acute episodes with remissions.

A family of RNA viruses causing INFLUENZA and other diseases. There are five recognized genera: INFLUENZAVIRUS A; INFLUENZAVIRUS B; INFLUENZAVIRUS C; ISAVIRUS; and THOGOTOVIRUS.

Immunoglobulins produced in a response to BACTERIAL ANTIGENS.

Lipid-protein complexes involved in the transportation and metabolism of lipids in the body. They are spherical particles consisting of a hydrophobic core of TRIGLYCERIDES and CHOLESTEROL ESTERS surrounded by a layer of hydrophilic free CHOLESTEROL; PHOSPHOLIPIDS; and APOLIPOPROTEINS. Lipoproteins are classified by their varying buoyant density and sizes.

An infectious disease caused by a spirochete, BORRELIA BURGDORFERI, which is transmitted chiefly by Ixodes dammini (see IXODES) and pacificus ticks in the United States and Ixodes ricinis (see IXODES) in Europe. It is a disease with early and late cutaneous manifestations plus involvement of the nervous system, heart, eye, and joints in variable combinations. The disease was formerly known as Lyme arthritis and first discovered at Old Lyme, Connecticut.

A specific species of bacteria, part of the BORRELIA BURGDORFERI GROUP, whose common name is Lyme disease spirochete.

Immunoglobulins produced in response to VIRAL ANTIGENS.

The functional hereditary units of BACTERIA.

Interruption or suppression of the expression of a gene at transcriptional or translational levels.

Tests that are dependent on the clumping of cells, microorganisms, or particles when mixed with specific antiserum. (From Stedman, 26th ed)

Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES).

A species of gram-negative bacteria originally isolated from urethral specimens of patients with non-gonoccocal URETHRITIS. In primates it exists in parasitic association with ciliated EPITHELIAL CELLS in the genital and respiratory tracts.

Specific hemagglutinin subtypes encoded by VIRUSES.

The outward appearance of the individual. It is the product of interactions between genes, and between the GENOTYPE and the environment.

Serum that contains antibodies. It is obtained from an animal that has been immunized either by ANTIGEN injection or infection with microorganisms containing the antigen.

The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.

The arrangement of two or more amino acid or base sequences from an organism or organisms in such a way as to align areas of the sequences sharing common properties. The degree of relatedness or homology between the sequences is predicted computationally or statistically based on weights assigned to the elements aligned between the sequences. This in turn can serve as a potential indicator of the genetic relatedness between the organisms.

Subunits of the antigenic determinant that are most easily recognized by the immune system and thus most influence the specificity of the induced antibody.

Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.

The type species of the genus INFLUENZAVIRUS A that causes influenza and other diseases in humans and animals. Antigenic variation occurs frequently between strains, allowing classification into subtypes and variants. Transmission is usually by aerosol (human and most non-aquatic hosts) or waterborne (ducks). Infected birds shed the virus in their saliva, nasal secretions, and feces.

Immunoglobulins produced in a response to PROTOZOAN ANTIGENS.

An order of slender, flexuous, helically coiled bacteria, with one or more complete turns in the helix.

A genus of flagellate intestinal EUKARYOTES parasitic in various vertebrates, including humans. Characteristics include the presence of four pairs of flagella arising from a complicated system of axonemes and cysts that are ellipsoidal to ovoidal in shape.

The insertion of recombinant DNA molecules from prokaryotic and/or eukaryotic sources into a replicating vehicle, such as a plasmid or virus vector, and the introduction of the resultant hybrid molecules into recipient cells without altering the viability of those cells.

Sensitive assay using radiolabeled ANTIGENS to detect specific ANTIBODIES in SERUM. The antigens are allowed to react with the serum and then precipitated using a special reagent such as PROTEIN A sepharose beads. The bound radiolabeled immunoprecipitate is then commonly analyzed by gel electrophoresis.

A genus of protozoa that comprise the malaria parasites of mammals. Four species infect humans (although occasional infections with primate malarias may occur). These are PLASMODIUM FALCIPARUM; PLASMODIUM MALARIAE; PLASMODIUM OVALE, and PLASMODIUM VIVAX. Species causing infection in vertebrates other than man include: PLASMODIUM BERGHEI; PLASMODIUM CHABAUDI; P. vinckei, and PLASMODIUM YOELII in rodents; P. brasilianum, PLASMODIUM CYNOMOLGI; and PLASMODIUM KNOWLESI in monkeys; and PLASMODIUM GALLINACEUM in chickens.

A species of gram-negative bacteria and causative agent of severe bovine ANAPLASMOSIS. It is the most pathogenic of the ANAPLASMA species.

A disease of cattle caused by parasitization of the red blood cells by bacteria of the genus ANAPLASMA.

Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.

The genetic constitution of the individual, comprising the ALLELES present at each GENETIC LOCUS.

The process of cumulative change at the level of DNA; RNA; and PROTEINS, over successive generations.

Substances that are recognized by the immune system and induce an immune reaction.

The regular and simultaneous occurrence in a single interbreeding population of two or more discontinuous genotypes. The concept includes differences in genotypes ranging in size from a single nucleotide site (POLYMORPHISM, SINGLE NUCLEOTIDE) to large nucleotide sequences visible at a chromosomal level.

A species of gram-negative bacteria in the genus ANAPLASMA, family ANAPLASMATACEAE, formerly called Ehrlichia phagocytophila or Ehrlichia equi. This organism is tick-borne (IXODES) and causes disease in horses and sheep. In humans, it causes human granulocytic EHRLICHIOSIS.

A species of LENTIVIRUS, subgenus equine lentiviruses (LENTIVIRUSES, EQUINE), causing acute and chronic infection in horses. It is transmitted mechanically by biting flies, mosquitoes, and midges, and iatrogenically through unsterilized equipment. Chronic infection often consists of acute episodes with remissions.

A subdiscipline of genetics which deals with the genetic basis of the immune response (IMMUNITY).

The degree of pathogenicity within a group or species of microorganisms or viruses as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenic capacity of an organism is determined by its VIRULENCE FACTORS.

Any detectable and heritable change in the genetic material that causes a change in the GENOTYPE and which is transmitted to daughter cells and to succeeding generations.

A species of gram-negative, aerobic BACTERIA. It is a commensal and pathogen only of humans, and can be carried asymptomatically in the NASOPHARYNX. When found in cerebrospinal fluid it is the causative agent of cerebrospinal meningitis (MENINGITIS, MENINGOCOCCAL). It is also found in venereal discharges and blood. There are at least 13 serogroups based on antigenic differences in the capsular polysaccharides; the ones causing most meningitis infections being A, B, C, Y, and W-135. Each serogroup can be further classified by serotype, serosubtype, and immunotype.

A family of recombinases initially identified in BACTERIA. They catalyze the ATP-driven exchange of DNA strands in GENETIC RECOMBINATION. The product of the reaction consists of a duplex and a displaced single-stranded loop, which has the shape of the letter D and is therefore called a D-loop structure.

Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.

In a prokaryotic cell or in the nucleus of a eukaryotic cell, a structure consisting of or containing DNA which carries the genetic information essential to the cell. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed)

The property of antibodies which enables them to react with some ANTIGENIC DETERMINANTS and not with others. Specificity is dependent on chemical composition, physical forces, and molecular structure at the binding site.

Methods used for studying the interactions of antibodies with specific regions of protein antigens. Important applications of epitope mapping are found within the area of immunochemistry.

Cell-surface components or appendages of bacteria that facilitate adhesion (BACTERIAL ADHESION) to other cells or to inanimate surfaces. Most fimbriae (FIMBRIAE, BACTERIAL) of gram-negative bacteria function as adhesins, but in many cases it is a minor subunit protein at the tip of the fimbriae that is the actual adhesin. In gram-positive bacteria, a protein or polysaccharide surface layer serves as the specific adhesin. What is sometimes called polymeric adhesin (BIOFILMS) is distinct from protein adhesin.

The biosynthesis of RNA carried out on a template of DNA. The biosynthesis of DNA from an RNA template is called REVERSE TRANSCRIPTION.

The sequential correspondence of nucleotides in one nucleic acid molecule with those of another nucleic acid molecule. Sequence homology is an indication of the genetic relatedness of different organisms and gene function.

Infections with species of the genus MYCOPLASMA.

Differential and non-random reproduction of different genotypes, operating to alter the gene frequencies within a population.

Any of the processes by which nuclear, cytoplasmic, or intercellular factors influence the differential control (induction or repression) of gene action at the level of transcription or translation.

A sequence of amino acids in a polypeptide or of nucleotides in DNA or RNA that is similar across multiple species. A known set of conserved sequences is represented by a CONSENSUS SEQUENCE. AMINO ACID MOTIFS are often composed of conserved sequences.

One of the three domains of life (the others being BACTERIA and ARCHAEA), also called Eukarya. These are organisms whose cells are enclosed in membranes and possess a nucleus. They comprise almost all multicellular and many unicellular organisms, and are traditionally divided into groups (sometimes called kingdoms) including ANIMALS; PLANTS; FUNGI; and various algae and other taxa that were previously part of the old kingdom Protista.

The genetic complement of a BACTERIA as represented in its DNA.

Large, hoofed mammals of the family EQUIDAE. Horses are active day and night with most of the day spent seeking and consuming food. Feeding peaks occur in the early morning and late afternoon, and there are several daily periods of rest.

An immunoassay utilizing an antibody labeled with an enzyme marker such as horseradish peroxidase. While either the enzyme or the antibody is bound to an immunosorbent substrate, they both retain their biologic activity; the change in enzyme activity as a result of the enzyme-antibody-antigen reaction is proportional to the concentration of the antigen and can be measured spectrophotometrically or with the naked eye. Many variations of the method have been developed.

In vitro method for producing large amounts of specific DNA or RNA fragments of defined length and sequence from small amounts of short oligonucleotide flanking sequences (primers). The essential steps include thermal denaturation of the double-stranded target molecules, annealing of the primers to their complementary sequences, and extension of the annealed primers by enzymatic synthesis with DNA polymerase. The reaction is efficient, specific, and extremely sensitive. Uses for the reaction include disease diagnosis, detection of difficult-to-isolate pathogens, mutation analysis, genetic testing, DNA sequencing, and analyzing evolutionary relationships.

Invertebrates or non-human vertebrates which transmit infective organisms from one host to another.

Gram-negative helical bacteria, in the genus BORRELIA, that are the etiologic agents of LYME DISEASE. The group comprises many specific species including Borrelia afzelii, Borellia garinii, and BORRELIA BURGDORFERI proper. These spirochetes are generally transmitted by several species of ixodid ticks.

The degree of similarity between sequences. Studies of AMINO ACID SEQUENCE HOMOLOGY and NUCLEIC ACID SEQUENCE HOMOLOGY provide useful information about the genetic relatedness of genes, gene products, and species.

Blood-sucking acarid parasites of the order Ixodida comprising two families: the softbacked ticks (ARGASIDAE) and hardbacked ticks (IXODIDAE). Ticks are larger than their relatives, the MITES. They penetrate the skin of their host by means of highly specialized, hooked mouth parts and feed on its blood. Ticks attack all groups of terrestrial vertebrates. In humans they are responsible for many TICK-BORNE DISEASES, including the transmission of ROCKY MOUNTAIN SPOTTED FEVER; TULAREMIA; BABESIOSIS; AFRICAN SWINE FEVER; and RELAPSING FEVER. (From Barnes, Invertebrate Zoology, 5th ed, pp543-44)

Diseases of domestic cattle of the genus Bos. It includes diseases of cows, yaks, and zebus.

An enzyme that catalyzes the hydrolysis of alpha-2,3, alpha-2,6-, and alpha-2,8-glycosidic linkages (at a decreasing rate, respectively) of terminal sialic residues in oligosaccharides, glycoproteins, glycolipids, colominic acid, and synthetic substrate. (From Enzyme Nomenclature, 1992)

Layers of protein which surround the capsid in animal viruses with tubular nucleocapsids. The envelope consists of an inner layer of lipids and virus specified proteins also called membrane or matrix proteins. The outer layer consists of one or more types of morphological subunits called peplomers which project from the viral envelope; this layer always consists of glycoproteins.

Genetic and antigenic variation of capsid protein VP7 of serotype G1 human rotavirus isolates. (1/863)

The deduced amino acid sequences of the outer capsid protein, VP7, of serotype G1 rotavirus clinical isolates collected over a 6 year period (1990-1995) in Melbourne, Australia, were examined. Phylogenetic analysis characterized the sequences into two discrete clusters representing two of the four global lineages of human G1 VP7 proteins. Antigenic characterization using a panel of serotype G1-specific neutralizing monoclonal antibodies classified lineage II isolates (1990-1993) as monotype G1a while lineage I isolates were classified as monotype G1b (1993-1995). Examination of the sequences of the neutralization epitope regions of VP7 revealed a particular amino acid substitution at residue 94 in region A (Asp --> Ser/Thr) that correlated with lineage and monotype designation. Our results indicated that temporal genetic variation of the VP7 of serotype G1 rotaviruses was associated with changes in the antigenicity of these isolates. (+info)

The major immunogenic epitopes of Epstein-Barr virus (EBV) nuclear antigen 1 are encoded by sequence domains which vary among nasopharyngeal carcinoma biopsies and EBV-associated cell lines. (2/863)

Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA-1) is a protein expressed consistently in EBV-infected cells and EBV-associated malignant tissues. A panel of monoclonal antibodies (MAbs) was generated against the C terminus of EBNA-1 and evaluated for the detection of EBNA-1 in different cell lines. The epitopes recognized were mapped. Since sequence variations of EBNA-1 have been reported in nasopharyngeal carcinoma (NPC) tissues and in infected healthy individuals, the ability of these MAbs to recognize a recombinant protein derived from an NPC biopsy was also analysed. MAb 4H11 appeared to react with EBNA-1 sequences from different sources, whereas MAbs 5C11, 5F12 and 8F6 failed to recognize a recombinant EBNA-1 protein cloned from an NPC patient. Using different recombinant EBNA-1 fragments in an immunoblot format, this study demonstrates that the domain bounded by amino acids 408 and 498 is very immunogenic in mice in that epitopes in this region are recognized by various MAbs. Amino acid sequences of EBNA-1 were also deduced from nucleotide sequences amplified from three Burkitt's lymphoma cell lines, two spontaneous lymphoblastoid cell lines, two NPC biopsies and one NPC hybrid cell line, NPC-KT, and compared to the sequence from B95-8. The amino acid sequence of EBNA-1 in Akata is almost identical to that in an NPC biopsy, except for amino acid 585. The results of this study indicate that the immunogenic epitopes of EBNA-1 are highly variable. (+info)

Antigenic variation in malaria: a 3' genomic alteration associated with the expression of a P. knowlesi variant antigen. (3/863)

Antigenic variation of malaria parasites was discovered in P. knowlesi, using a schizont-infected cell agglutination (SICA) assay to detect variant antigens expressed at the surface of infected erythrocytes. Later studies utilizing stable clones, Pk1(A+) and its direct derivative, Pk1(B+)1+, showed that SICA[+] clones express distinct parasite-encoded antigens of approximately 200 kDa. Here we identify a P. knowlesi variant antigen gene and cDNA and demonstrate that it encodes the 205 kDa variant antigen expressed by B+ parasites. This gene belongs to a multigene family, which we term SICAvar. Its ten-exon structure with seven cysteine-rich coding modules is unique compared to P. falciparum var genes. Further, we highlight a 3' genomic alteration that we predict is related to SICAvar gene switching. (+info)

Phase variations of the Mycoplasma penetrans main surface lipoprotein increase antigenic diversity. (4/863)

Mycoplasma penetrans is a recently identified mycoplasma, isolated from urine samples collected from human immunodeficiency virus (HIV)-infected patients. Its presence is significantly associated with HIV infection. The major antigen recognized during natural and experimental infections is an abundant P35 lipoprotein which, upon extraction, segregates in the Triton X-114 detergent phase and is the basis of M. penetrans-specific serological assays. We report here that the P35 antigen undergoes spontaneous and reversible phase variation at high frequency, leading to heterogeneous populations of mycoplasmas, even when derived from a clonal lineage. This variation was found to be determined at the transcription level, and although this property is not unique among the members of the class Mollicutes, the mechanism by which it occurs in M. penetrans differs from those previously described for other Mycoplasma species. Indeed, the P35 phase variation was due neither to a p35 gene rearrangement nor to point mutations within the gene itself or its promoter. The P35 phase variation in the different variants obtained was concomitant with modifications in the pattern of other expressed lipoproteins, probably due to regulated expression of selected members of a gene family which was found to potentially encode similar lipoproteins. M. penetrans variants could be selected on the basis of their lack of colony immunoreactivity with a polyclonal antiserum against a Triton X-114 extract, strongly suggesting that the mechanisms involved in altering surface antigen expression might allow evasion of the humoral immune response of the infected host. (+info)

Molecular and functional analysis of a conserved CTL epitope in HIV-1 p24 recognized from a long-term nonprogressor: constraints on immune escape associated with targeting a sequence essential for viral replication. (5/863)

It has been hypothesized that sequence variation within CTL epitopes leading to immune escape plays a role in the progression of HIV-1 infection. Only very limited data exist that address the influence of biologic characteristics of CTL epitopes on the emergence of immune escape variants and the efficiency of suppression HIV-1 by CTL. In this report, we studied the effects of HIV-1 CTL epitope sequence variation on HIV-1 replication. The highly conserved HLA-B14-restricted CTL epitope DRFYKTLRAE in HIV-1 p24 was examined, which had been defined as the immunodominant CTL epitope in a long-term nonprogressing individual. We generated a set of viral mutants on an HX10 background differing by a single conservative or nonconservative amino acid substitution at each of the P1 to P9 amino acid residues of the epitope. All of the nonconservative amino acid substitutions abolished viral infectivity and only 5 of 10 conservative changes yielded replication-competent virus. Recognition of these epitope sequence variants by CTL was tested using synthetic peptides. All mutations that abrogated CTL recognition strongly impaired viral replication, and all replication-competent viral variants were recognized by CTL, although some variants with a lower efficiency. Our data indicate that this CTL epitope is located within a viral sequence essential for viral replication. Targeting CTL epitopes within functionally important regions of the HIV-1 genome could limit the chance of immune evasion. (+info)

Spontaneous regression of primary autoreactivity during chronic progression of experimental autoimmune encephalomyelitis and multiple sclerosis. (6/863)

Experimental autoimmune encephalomyelitis (EAE) is a widely used animal model for multiple sclerosis (MS). EAE is typically initiated by CD4(+) T helper cell type 1 (Th1) autoreactivity directed against a single priming immunodominant myelin peptide determinant. Recent studies have shown that clinical progression of EAE involves the accumulation of neo-autoreactivity, commonly referred to as epitope spreading, directed against peptide determinants not involved in the priming process. This study directly addresses the relative roles of primary autoreactivity and secondary epitope spreading in the progression of both EAE and MS. To this end we serially evaluated the development of several epitope-spreading cascades in SWXJ mice primed with distinctly different encephalitogenic determinants of myelin proteolipid protein. In a series of analogous experiments, we examined the development of epitope spreading in patients with isolated monosymptomatic demyelinating syndrome as their disease progressed to clinically definite MS. Our results indicate that in both EAE and MS, primary proliferative autoreactivity associated with onset of clinical disease invariably regresses with time and is often undetectable during periods of disease progression. In contrast, the emergence of sustained secondary autoreactivity to spreading determinants is consistently associated with disease progression in both EAE and MS. Our results indicate that chronic progression of EAE and MS involves a shifting of autoreactivity from primary initiating self-determinants to defined cascades of secondary determinants that sustain the self-recognition process during disease progression. (+info)

Antigenic heterogeneity of the hepatitis C virus NS4 protein as modeled with synthetic peptides. (7/863)

The effect of sequence heterogeneity on the immunologic properties of two strong antigenic regions of the hepatitis C virus (HCV) NS4 protein was studied by using a set of 443 overlapping 20-mer synthetic peptides. One antigenic region comprising the cleavage site between NS4a and NS4b (region 5-1-1) was modeled with peptides derived from 73 different known sequences, representing HCV genotypes 1-6. The other antigenic region, designated region 59 and located at the C-terminus of the NS4b protein, was modeled with peptides from 7 known sequences representing genotypes 1-3. All peptides were tested for antigenic reactivity by enzyme immunoassay with a panel of anti-HCV-positive serum specimens representing genotypes 1-5. The data demonstrated that immunoreactive peptides fell into two groups. One group, represented by N-terminal peptides, demonstrated genotype-independent immunoreactivity; the other group, from the central part of region 5-1-1, showed strict genotype specificity. Nineteen peptides from the genotype-independent group strongly immunoreacted with a wide range of serum samples containing antibodies to all 5 HCV genotypes. Twenty-five peptides from the genotype-specific group were found to strongly react with serum containing antibodies only to the genotype from which the peptides were derived. Similar to the N-terminal part of region 5-1-1, peptides derived from region 59 did not show genotype-specific immunoreactivity. Some peptides derived from the central part of region 59 showed very strong and broad antigenic reactivity. Thus, after examining two antigenic regions of the NS4 protein, we identified short sequences that can be used for the efficient detection of either genotype-independent or genotype-specific HCV antibodies. (+info)

Structural and evolutionary inference from molecular variation in Neisseria porins. (8/863)

The porin proteins of the pathogenic Neisseria species, Neisseria gonorrhoeae and Neisseria meningitidis, are important as serotyping antigens, putative vaccine components, and for their proposed role in the intracellular colonization of humans. A three-dimensional structural homology model for Neisseria porins was generated from Escherichia coli porin structures and N. meningitidis PorA and PorB sequences. The Neisseria sequences were readily assembled into the 16-strand beta-barrel fold characteristic of porins, despite relatively low sequence identity with the Escherichia proteins. The model provided information on the spatial relationships of variable regions of peptide sequences in the PorA and PorB trimers and insights relevant to the use of these proteins in vaccines. The nucleotide sequences of the porin genes from a number of other Neisseria species were obtained by PCR direct sequencing and from GenBank. Alignment and analysis of all available Neisseria porin sequences by use of the structurally conserved regions derived from the PorA and PorB structural models resulted in the recovery of an improved phylogenetic signal. Phylogenetic analyses were consistent with an important role for horizontal genetic exchange in the emergence of different porin classes and confirmed the close evolutionary relationships of the porins from N. meningitidis, N. gonorrhoeae, Neisseria lactamica, and Neisseria polysaccharea. Only members of this group contained three conserved lysine residues which form a potential GTP binding site implicated in pathogenesis. The model placed these residues on the inside of the pore, in close proximity, consistent with their role in regulating pore function when inserted into host cells. (+info)

Many of the proteins known to show antigenic or phase variation are related to virulence. Antigenic variation in bacteria is ... shows that some DNA viruses have the same high rates of antigenic variation as their RNA counterparts. Antigenic variation ... making it one of the mechanisms of antigenic escape. It is related to phase variation. Antigenic variation not only enables the ... Antigenic variation may be classified into two types, antigenic drift that results from a change in few amino acids and ...

https://en.wikipedia.org/wiki/Antigenic_variation

... a role in antigenic variation?". Nucleic Acids Research. 12 (10): 4153-70. doi:10.1093/nar/12.10.4153. PMC 318823. PMID 6328412 ...

https://en.wikipedia.org/wiki/Tet_methylcytosine_dioxygenase_2

Scherf, Artur; Lopez-Rubio, Jose Juan; Riviere, Loïc (October 2008). "Antigenic Variation in Plasmodium falciparum". Annual ... Guizetti, Julien; Scherf, Artur (May 2013). "Silence, activate, poise and switch! Mechanisms of antigenic variation in". ... Cross, George A. M. (April 1996). "Antigenic variation in trypansosomes: Secrets surface slowly". BioEssays. 18 (4): 283-291. ... "The large diverse gene family var encodes proteins involved in cytoadherence and antigenic variation of plasmodium falciparum- ...

https://en.wikipedia.org/wiki/Subtelomere

Scherf A, Lopez-Rubio JJ, Riviere L (2008). "Antigenic variation in Plasmodium falciparum". Annual Review of Microbiology. 62 ( ... Kyes SA, Kraemer SM, Smith JD (September 2007). "Antigenic variation in Plasmodium falciparum: gene organization and regulation ... "The large diverse gene family var encodes proteins involved in cytoadherence and antigenic variation of Plasmodium falciparum- ... This variation gives rise to different types of PfEMP1. The DBL-CIDR combination in a particular type of PfEMP1 protein is ...

https://en.wikipedia.org/wiki/Plasmodium_falciparum_erythrocyte_membrane_protein_1

This is called antigenic variation. An example is HIV, which mutates rapidly, so the proteins on its viral envelope that are ... The B cell then displays these antigenic peptides on its surface MHC class II molecules. This combination of MHC and antigen ... Welling GW, Weijer WJ, van der Zee R, Welling-Wester S (September 1985). "Prediction of sequential antigenic regions in ... Fc receptor Immune system receptors Immunostimulator Neuroimmune system Original antigenic sin - when the immune system uses ...

https://en.wikipedia.org/wiki/Immune_system

Antigenic variation of Latinamerican rotavirus. Structural studies of the rotavirus inner capsid. Gene sequence of some ... Puerto Manzano, F; Avendano, L; Esparza, J; Caul, EO (Dec 1984). "Antigenic variation in Latin American human pararotaviruses ( ...

https://en.wikipedia.org/wiki/José_Esparza

World Health Organization (1972). "ANTIGENIC VARIATION IN INFLUENZA A VIRUSES". Weekly Epidemiological Record. 47: 381. hdl: ... Through April 1972, little antigenic difference from the original Hong Kong virus was noted on the whole among circulating ...

https://en.wikipedia.org/wiki/London_flu

Thirteen years of his group's malaria research on antigenic variation in malaria culminated in the first molecular cloning of ... Howard, R. J.; Barnwell, J. W.; Kao, V. (1 July 1983). "Antigenic variation of Plasmodium knowlesi malaria: identification of ... Howard, RJ (13 November 1984). "Antigenic variation of bloodstage malaria parasites". Philosophical Transactions of the Royal ... to the molecular pathogenesis of human cerebral malaria and the role of parasite antigenic variation and infected cell ...

https://en.wikipedia.org/wiki/Russell_J._Howard

It became apparent once the extent of antigenic variation in the virus was recognized that a new vaccine would be needed to ... World Health Organization (1972). "ANTIGENIC VARIATION IN INFLUENZA A VIRUSES". Weekly Epidemiological Record. 47: 381. hdl: ... The virus was descended from H2N2 (which caused the Asian flu pandemic in 1957-1958) through antigenic shift, a genetic process ... The novel virus was thereafter designated H3N2, indicating its partial similarity to H2N2 but also its antigenic distinction. ...

https://en.wikipedia.org/wiki/Hong_Kong_flu

Barry JD, McCulloch R (2001). "Antigenic variation in trypanosomes: enhanced phenotypic variation in a eukaryotic parasite". ... The antigenic variation causes cyclical waves of parasitemia, which is one of the characteristics of Human African ... Periodic antigenic variation - the VSG coat undergoes frequent stochastic genetic modification-'switching'-allowing variants ... This antigenic variation creates cyclical waves of parasitemia characteristic of Human African Trypanosomiasis. Antigen ' ...

https://en.wikipedia.org/wiki/Variant_surface_glycoprotein

Kinetoplast DNA and Antigenic Variation. Krips Repro b.V., Netherlands. "Jan Hoeijmakers, CV (as of the end of 2013)". Archived ... Kinetoplast DNA and Antigenic Variation . At Erasmus University Rotterdam, as a member of Dirk Bootsma's group in the Institute ... in which he clarified the molecular mechanism of the antigen variation of trypanosomes. He uncovered the structure and main ...

https://en.wikipedia.org/wiki/Jan_Hoeijmakers

van der Woude MW, Bäumler AJ (2004). "Phase and antigenic variation in bacteria". Clin Microbiol Rev. 17 (3): 581-611. doi: ... Wisniewski-Dyé F, Vial L (2008). "Phase and antigenic variation mediated by genome modifications". Antonie van Leeuwenhoek. 94 ... It involves the variation of protein expression, frequently in an on-off fashion, within different parts of a bacterial ... In this form of phase variation. The promoter region of the genome can move from one copy of a gene to another through ...

https://en.wikipedia.org/wiki/Phase_variation

Important questions about antigenic variation are also relevant for such research areas as developing a vaccine against HIV and ... Antigenic variation is common among pathogenic organisms. These include the agents of malaria, gonorrhea, and sleeping sickness ... through antigenic variation. Essentially, the pathogen stays one step ahead of antibodies by changing its surface proteins. ... which is sufficient to create a new antigenic "identity" for the organism. Antibodies in the blood that are binding to and ...

https://en.wikipedia.org/wiki/Relapsing_fever

Prucca CG, Slavin I, Quiroga R, Elias EV, Rivero FD, Saura A, Carranza PG, Lujan HD (2008). "Antigenic variation in Giardia ... 2008). "Antigenic variation in Giardia lamblia is regulated by RNA interference". Nature. 456 (7223): 750-4. Bibcode:2008Natur. ... called antigenic variation). Gillin's work reveals why Giardia infections are extremely persistent and prone to recur. In ... Svärd SG, Meng TC, Hetsko ML, McCaffery JM, Gillin FD (1998). "Differentiation-associated surface antigen variation in the ...

https://en.wikipedia.org/wiki/Giardia_duodenalis

Harrison B & Robinson D (1999). Natural genomic and antigenic variation in whitefly-transmitted geminiviruses (begomoviruses). ... There is variation in the literature on this score, however, with other sources citing a 4-hour acquisition time and 4-hour ... Little to no infection occurs after three months, and variation in spread was due to change in temperature, radiation and ...

https://en.wikipedia.org/wiki/Cassava_mosaic_virus

The virulence factor that M. penetrans displays is antigenic variation, the ability to exchange or switch antigens against ... Horino, A.; Sasaki, Y.; Sasaki, T.; Kenri, T. (2003-01-01). "Multiple Promoter Inversions Generate Surface Antigenic Variation ... penetrans antigenic variation. Mycoplasma penetrans has been shown to hinder p53, a tumor suppressing gene that aids in ... In M. penetrans, this promoter region can undergo reversible inversion, allowing for variation in antigen production and, thus ...

https://en.wikipedia.org/wiki/Mycoplasma_penetrans

All are antigenic and all exhibit antigenic variation (see below). The pili exhibit the most variation. The pili, Opa proteins ... pilin antigenic variation in the pathogenic Neisseria: Pilin antigenic variation". Molecular Microbiology. 81 (5): 1136-1143. ... Phase variation is similar to antigenic variation, but instead of changes at the genetic level altering the composition of ... Pili are varied by antigenic variation, but also phase variation. Frameshifts occur in both the pilE and pilC genes, ...

https://en.wikipedia.org/wiki/Neisseria_gonorrhoeae

Its most prevalent mechanism is its ability to evade recognition by antibodies through antigenic variation. This is achieved ... One cause of antigenic escape is that a pathogen's epitopes (the binding sites for immune cells) become too similar to a ... However, variation of this coat can lead to antibodies being unable to recognize and eliminate the antigen. In addition to this ... Antigenic escape, immune escape, immune evasion or escape mutation occurs when the immune system of a host, especially of a ...

https://en.wikipedia.org/wiki/Antigenic_escape

"Transient cross-reactive immune responses can orchestrate antigenic variation in malaria". Nature. 429 (6991): 555-558. Bibcode ... "The generation of influenza outbreaks by a network of host immune responses against a limited set of antigenic types". ...

https://en.wikipedia.org/wiki/Sunetra_Gupta

Morrison LJ, Marcello L, McCulloch R; Marcello; McCulloch (December 2009). "Antigenic variation in the African trypanosome: ...

https://en.wikipedia.org/wiki/Trypanosomatida

Unfortunately, vaccines are not effective with Chagas disease due to antigenic variation. This pathogen causes damage to the ... but vaccines can not be used due to antigenic variation.[citation needed] Amoebozoa are characterized by the use of pseudopodia ...

https://en.wikipedia.org/wiki/Protozoan_infection

Clements, JE; Pedersen FS; Narayan O; Haseltine WA (1980). "Genomic Changes Associated with Antigenic Variation of Visna Virus ... Terwilliger, EF; Langhoff E; Gabuzda D; Haseltine W; Haseltine, W. A. (1991). "Allelic variation in the effects of nef on HIV-1 ...

https://en.wikipedia.org/wiki/William_A._Haseltine

Barrett, Pastoret & Taylor 2006, p. 24 Chen J, Deng YM (2009). "Influenza virus antigenic variation, host antibody production ... Other viruses change more slowly as mutations in their genes gradually accumulate over time, a process known as antigenic drift ...

https://en.wikipedia.org/wiki/Viral_evolution

Biswas B, Vemulapalli R, Dutta SK (August 1998). "Molecular basis for antigenic variation of a protective strain-specific ... Strain variation among isolates can be determined by identifying surface antigens or by performing whole-genome sequencing. ... Molecular analysis surface antigens has found significant genetic and phenotypic variation in strains of N. risticii, these ... Chaichanasiriwithaya W, Rikihisa Y, Yamamoto S, Reed S, Crawford TB, Perryman LE, Palmer GH (December 1994). "Antigenic, ...

https://en.wikipedia.org/wiki/Neorickettsia_risticii

A DNA transposition mechanism for antigenic variation in African trypanosomes (9) (10) (11) (12). Transsplicing as an essential ... Bitter W, Gerrits H, Kieft R, Borst P. The role of transferrin-receptor variation in the host range of Trypanosoma brucei. ... J, a new base in the DNA of trypanosomes and related parasites (30) (31). Variation in the transferrin receptor allows African ...

https://en.wikipedia.org/wiki/Piet_Borst

Similar to HIV-escape, cancer can escape the immune system's detection by antigenic variation. As the immunodominant epitope is ... Immunodominance is the immunological phenomenon in which immune responses are mounted against only a few of the antigenic ... That is, despite multiple allelic variations of MHC molecules and multiple peptides presented on antigen presenting cells, the ...

https://en.wikipedia.org/wiki/Immunodominance

Antigenic variation prevents the development of cross immunity to the various strains of O. tsutsugamushi. An infected ... As of 2009, more than 20 different strains have been established in humans based on antigenic variation using serological tests ... "Demonstration of antigenic and genotypic variation in Orientia tsutsugamushi which were isolated in Japan, and their ... DNA analyses have shown that the GroES and GroEL genes are indeed present in O. tsutsugamushi with slight variation in ...

https://en.wikipedia.org/wiki/Orientia_tsutsugamushi

Many genes involved in antigenic variation are located in the subtelomeric regions of the chromosomes. These are divided into ...

https://en.wikipedia.org/wiki/Plasmodium_falciparum

Dai Q, Restrepo BI, Porcella SF, Raffel SJ, Schwan TG, Barbour AG (June 2006). "Antigenic variation by Borrelia hermsii occurs ...

https://en.wikipedia.org/wiki/Borrelia_hermsii

Among its virulence factors are its capsule, endotoxins, siderophores, antimicrobial resistance and antigenic phase variation. ...

https://en.wikipedia.org/wiki/Klebsiella_granulomatis

A hypothesis for the origin of this genetic variation states that the host-defense system responsible for silencing foreign DNA ... Bookmarking Original antigenic sin, immunological imprinting Metabolic imprinting Ferguson-Smith AC (July 2011). "Genomic ... Natural selection for genomic imprinting requires genetic variation in a population. ...

https://en.wikipedia.org/wiki/Genomic_imprinting

... antigenic variation of the VlsE surface protein, inactivating key immune components such as complement, and hiding in the ... Is it a new tick borne disease or Lyme disease variation?". Brazilian Journal of Medical and Biological Research. 40 (4): 443- ...

https://en.wikipedia.org/wiki/Lyme_disease

Carrell RW, Jeppsson JO, Laurell CB, Brennan SO, Owen MC, Vaughan L, Boswell DR (July 1982). "Structure and variation of human ... Consequently, carbamylated A1AT is currently being developed as an antigenic biomarker for RA. The protein was initially named ... "NM_001127701.1(SERPINA1):c.1096G>A (p.Glu366Lys)". ClinVar Genomic variation as it relates to human health. U.S. National ... as an antigenic target of anti-CarP antibodies in patients with rheumatoid arthritis". Journal of Autoimmunity. 80: 77-84. doi: ...

https://en.wikipedia.org/wiki/Alpha-1_antitrypsin

The ability of various influenza strains to show species-selectivity is largely due to variation in the hemagglutinin genes. ... genetic drift and antigenic shift - in viruses in poultry and swine which the fort bred for local consumption. Though initial ...

https://en.wikipedia.org/wiki/Spanish_flu_research

Enormous antigenic variation in Orientia tsutsugamushi strains is now recognized, and immunity to one strain does not confer ... A vaccine developed for one locality may not be protective in another, because of antigenic variation. This complexity ... 2003). "Short report: variation in the 56-kD type-specific antigen gene of Orientia tsutsugamushi isolated from patients in ... Kang JS, Chang WH (1999). "Antigenic relationship among the eight prototype and new serotype strains of Orientia tsutsugamushi ...

https://en.wikipedia.org/wiki/Scrub_typhus

Flu became more widely referred to as coqueluche and coccolucio in France and Sicily during this pandemic, variations of which ... in which cross-species infections trigger antigenic shift and create new strains of flu human beings have little immunity to. ...

https://en.wikipedia.org/wiki/1510_influenza_pandemic

"Periodic variation in side-chain polarities of T-cell antigenic peptides correlates with their structure and activity". ... DeLisi, C.; Berzofsky, J. A. (1985). "T-cell antigenic sites tend to be amphipathic structures". Proceedings of the National ...

https://en.wikipedia.org/wiki/Charles_DeLisi

This displaces the antigenic peptide away from the TCR and circumvents the normal mechanism for T-cell activation. The ... Arcus VL, Proft T, Sigrell JA, Baker HM, Fraser JD, Baker EN (May 2000). "Conservation and variation in superantigen structure ... 2003). "Identification of the Antigenic Epitopes in Staphylococcal Enterotoxins A and E and Design of a Superantigen for Human ... "High-frequency intracellular infection and erythrogenic toxin A expression undergo phase variation in M1 group A streptococci ...

https://en.wikipedia.org/wiki/Superantigen

In wild birds, within-subtype antigenic variation appears to be limited but has been observed in poultry. Antigenic shift is a ... Two key processes that influenza viruses evolve through are antigenic drift and antigenic shift. Antigenic drift is when an ... Antigenic drift occurs in all influenza species but is slower in B than A and slowest in C and D. Antigenic drift is a major ... ICV and IDV experience a slower rate of antigenic evolution than IAV and IBV. Because of this antigenic stability, relatively ...

https://en.wikipedia.org/wiki/Influenza

There are 18 and 11 subtypes of hemagglutinin and neuraminidase respectively which allow variations of the virus surface ... "Inhibition of virus-induced hemolysis with monoclonal antibodies to different antigenic areas on the hemagglutinin molecule of ...

https://en.wikipedia.org/wiki/Type_A_influenza_vaccine

PAL labeling can be confusing to consumers, especially as there can be many variations on the wording of the warning. PAL is ... Other formulas, based on free amino acids, are the least antigenic and provide complete nutritional support in severe forms of ... However, for the soybean proteins known to trigger allergic reactions, there is more variation from strain to strain than ... Hypoallergenic infant formulas can be based on proteins partially predigested to a less antigenic form. ...

https://en.wikipedia.org/wiki/Food_allergy

There is little geographical variation, with some minor local differences in the amount of orange on the belly. In 1915, ... In 1966, a paramyxovirus with some antigenic similarity to Newcastle disease was isolated from the brain of a turquoise parrot ... Observations at Chiltern in Victoria indicated seasonal variation in flock size, with turquoise parrots foraging in groups of 5 ...

https://en.wikipedia.org/wiki/Turquoise_parrot

In 1965 and 1972, several groups characterized how P. knowlesi antigenic variation contributed to immune evasion and chronic ...

https://en.wikipedia.org/wiki/Plasmodium_knowlesi

... is a kind of genetic variation in viruses, arising from the accumulation of mutations in the virus genes that ... Antigenic drift occurs in both influenza A and influenza B viruses. (Confusion can arise with two very similar terms, antigenic ... Antigenic drift is this continuous process of genetic and antigenic change among flu strains. In human populations, immune ( ... Antigenic drift should not be confused with antigenic shift, which refers to reassortment of the virus' gene segments. As well ...

https://en.wikipedia.org/wiki/Antigenic_drift

Development of a vaccine has been complicated by the ongoing evolution of resistant strains and antigenic variation (the ...

https://en.wikipedia.org/wiki/Gonorrhea

Glenny A, Pope C, Waddington H, Wallace U (1926). "The antigenic value of toxoid precipitated by potassium alum". J Pathol ... significant variations in the efficacy of different batches of the same vaccine were correctly assumed to be caused by ... Because immune systems have evolved to recognize these specific antigenic moieties, the presence of an adjuvant in conjunction ...

https://en.wikipedia.org/wiki/Immunologic_adjuvant

The virus is divided into four major serotypes (adr, adw, ayr, ayw) based on antigenic epitopes present on its envelope ... and forty subgenotypes according to overall nucleotide sequence variation of the genome. The genotypes have a distinct ...

https://en.wikipedia.org/wiki/Hepatitis_B_virus

An interesting variation of this idea is the use of genetically modified cells that can produce custom-tailored ribozymes. This ... Vaccination involves the introduction (i.e. via injection) of a small amount of typically inactivated or attenuated antigenic ... Moreover, the major difficulty in developing vaccines and anti-viral drugs is due to viral variation. The emergence of ... This effect, called the quasispecies model, results in immense variation in any given sample of virus, and gives the ...

https://en.wikipedia.org/wiki/Antiviral_drug

"Loss-of-function variations within the filaggrin gene predispose for atopic dermatitis with allergic sensitizations". The ... "Citrulline is an essential constituent of antigenic determinants recognized by rheumatoid arthritis-specific autoantibodies". ...

https://en.wikipedia.org/wiki/Filaggrin

While most strains are beneficial, there are significant phenotypic variations among strains, even those that share >99% of ... especially because it is versatile not only in its antigenic and pathogenic behaviors, but also in its cell morphology. C. ... "Genomic variation landscape of the human gut microbiome". Nature. 493 (7430): 45-50. Bibcode:2013Natur.493...45S. doi:10.1038/ ...

https://en.wikipedia.org/wiki/Citrobacter_freundii

However, the antigenic cross-reactivity among these two representatives within the genus Respirovirus may explain why SeV ... This difference results in different neuraminidase conformations around the receptor binding site and variations in ... The virus genome has high similarity with human parainfluenza virus 1 (HPIV-1) and the two viruses share common antigenic ... Human parainfluenza virus type 1, also shares common antigenic determinants with SeV and triggers the generation of cross- ...

https://en.wikipedia.org/wiki/Murine_respirovirus

The severity and variation in symptoms correlates with the region the case develops in. This could be due to climatic factors ... ORF2 encode the structural proteins, which are -at least- VP26, VP29 and VP32, the most antigenic and immunogenic of these ... Royuela E, Sánchez-Fauquier A (January 2010). "Molecular cloning, expression and first antigenic characterization of human ...

https://en.wikipedia.org/wiki/Astrovirus

Variations in these factors could lead to different strengths of immune response toward the newly formed antigenic determinant ...

https://en.wikipedia.org/wiki/Hapten

However, due to the amino acid variation between different proteins, molecular mimicry should not happen from a probability ... Molecular mimicry is thus occurring between two recognized peptides that have similar antigenic surfaces in the absence of ... "Similar antigenic surfaces, rather than sequence homology, dictate T-cell epitope molecular mimicry". Proceedings of the ... which leads to the expression of novel receptor specificity through V region gene rearrangements which will create variation in ...

https://en.wikipedia.org/wiki/Molecular_mimicry

Antigenic variation has always complicated influenza vaccine formulation. The occurrence of viruses that exhibit antigenic ... Current Trends Antigenic Variation of Recent Influenza A(H3N2) Viruses Analysis of recent influenza A(H3N2) viruses indicates ... This response confirms the existence of antigenic variation in recent virus isolates. Vaccinees in all age groups developed ... Although antigenic variants differ in some epitopes on the hemagglutinin, they also share other common hemagglutinin epitopes. ...

https://www.cdc.gov/mmwr/preview/mmwrhtml/00001033.htm

... 0-9. A. B. C. D. E. F. G. H. I. J. K. L. M. N. O. P. Q. R. S. T. U. ...

https://apps.who.int/iris/handle/10665/197911/browse?authority=Antigenic+Variation&type=mesh

Immunity to malaria : antigenic variation in chronic infections of Plasmodium knowlesi / by K. N. Brown, I. N. Brown ...

https://extranet.who.int/iris/restricted/browse?authority=Antigenic+Variation&type=mesh

Canine Influenza Virus A(H3N2) Clade with Antigenic Variation, China, 2016-2017 Yanli Lyu1, Shikai Song1, Liwei Zhou1, Guoxia ... Canine Influenza Virus A(H3N2) Clade with Antigenic Variation, China, 2016-2017. ... Antigenic cartograph representative of hemagglutinin inhibition (HI) titers of canine influenza viruses, China, 2009-2017, ... showing antigenic groups A-C. Map was generated by using AntigenMap 3D (http://sysbio.cvm.msstate.edu/software/AntigenMap) and ...

https://wwwnc.cdc.gov/eid/article/25/1/17-1878-f2

Using the example of a model of antigenic variation in malaria, we show how many of the observed dynamical regimes can be ... Title:The effects of symmetry on the dynamics of antigenic variation. Authors:K. B. Blyuss ... an important role is played by the structure of antigenic variants associated with a pathogen. ... explained in terms of the symmetry of interactions between different antigenic variants. The results of this analysis are quite ...

https://arxiv.org/abs/1202.4290v1

Antigenic variation among strains of the New Jersey serotype of vesicular stomatitis virus. American journal of veterinary ... Tesh, R. B. / Antigenic variation among strains of the New Jersey serotype of vesicular stomatitis virus. In: American journal ... Antigenic variation among strains of the New Jersey serotype of vesicular stomatitis virus. / Tesh, R. B. ... Tesh, R. B. (1979). Antigenic variation among strains of the New Jersey serotype of vesicular stomatitis virus. American ...

https://researchexperts.utmb.edu/en/publications/antigenic-variation-among-strains-of-the-new-jersey-serotype-of-v

Antigenic variation of a relapsing fever Borrelia species. Annu Rev Microbiol. 1990. 44:155-71. [QxMD MEDLINE Link]. [Full Text ...

https://emedicine.medscape.com/article/227272-workup

We conclude that MRN promotes stringent homologous recombination at subtelomeric loci and restrains antigenic variation. ... and is especially important for recombination of the subtelomeric variant surface glycoprotein during antigenic variation. ... The MRN complex promotes DNA repair by homologous recombination and restrains antigenic variation in African trypanosomes Ann- ... We conclude that MRN promotes stringent homologous recombination at subtelomeric loci and restrains antigenic variation. ...

https://hal-pasteur.archives-ouvertes.fr/pasteur-03112362

Antigenic variation of pili * Protein Por B 1A on the outer membrane - This inhibits host factor H and C4-binding protein, ...

https://www.medscape.com/answers/333612-116551/what-are-racial-predilections-of-gonococcal-arthritis

Canine Influenza Virus A(H3N2) Clade with Antigenic Variation, China, 2016-2017. Emerging Infectious Diseases. 2019;25(1):161- ... Canine Influenza Virus A(H3N2) Clade with Antigenic Variation, China, 2016-2017 On This Page ... Canine Influenza Virus A(H3N2) Clade with Antigenic Variation, China, 2016-2017. Volume 25, Number 1-January 2019 ... Canine Influenza Virus A(H3N2) Clade with Antigenic Variation, China, 2016-2017. ...

https://wwwnc-origin.cdc.gov/eid/article/25/1/17-1878_article

Empirical comparison of patterns of genetic variation at antigenic and neutral sites supports this role for immune selection in ... The model explicitly considers the extensive diversity of multi-copy genes that undergo antigenic variation via sequential, ... Keywords: Other; Plasmodium falciparum; antigenic diversity; epidemiological dynamics; immune selection; parasite population ... structures the parasite population into a subset of coexisting dominant repertoires of var genes whose degree of antigenic ...

https://pubmed.ncbi.nlm.nih.gov/23251784/

We examine the properties of a recently proposed model for antigenic variation in malaria which incorporates multiple epitopes ... We examine the properties of a recently proposed model for antigenic variation in malaria which incorporates multiple epitopes ... Algorithms, Animals, Antibody Formation, Antigenic Variation, Computer Simulation, Cross Reactions, Epitopes, Humans, Immune ...

https://www.medawar.ox.ac.uk/publications/210129?e755aff6-759e-11ed-996e-0a3af28e70c2

Structural and serological evidence for a novel mechanism of antigenic variation in foot-and-mouth disease virus ... Structural and serological evidence for a novel mechanism of antigenic variation in foot-and-mouth disease virus ...

https://www.camsoxford.ox.ac.uk/coi-publications/publications/430757

... structure of the sequences and their division into subgroups may reflect the conflicting problems of maximizing antigenic ... Plasmodium falciparum antigenic variation. Mapping mosaic var gene sequences onto a network of shared, highly polymorphic ... Plasmodium falciparum antigenic variation. Mapping mosaic var gene sequences onto a network of shared, highly polymorphic ... Amino Acid Sequence, Animals, Antigenic Variation, Antigens, Protozoan, Child, Conserved Sequence, Humans, Malaria, Falciparum ...

https://www.ndm.ox.ac.uk/publications/11542

Immunodominance and Antigenic Variation of Influenza Virus Hemagglutinin: Implications for Design of Universal Vaccine ... Composition and Antigenic Effects of Individual Glycan Sites of a Trimeric HIV-1 Envelope Glycoprotein journal, March 2016 * ...

https://www.osti.gov/pages/biblio/1483019-hiv-envelope-glycoform-heterogeneity-localized-diversity-govern-initiation-maturation-v2-apex-broadly-neutralizing-antibody-lineage

Mutations in SARS-CoV-2 Leading to Antigenic Variations in Spike Protein: A Challenge in Vaccine Development. Praveen Kumar ... The significant variations in the predicted epitopes showing high antigenicity were A348V, V367F and A419S in receptor binding ... One of the major reasons attributed to this variation is genetic mutation. Therefore, we aimed to predict the mutations in the ... Conclusion S protein is the major target for vaccine development, but several mutations were predicted in the antigenic ...

https://www.thieme-connect.com/products/ejournals/abstract/10.1055/s-0040-1715790

Categories: Antigenic Variation Image Types: Photo, Illustrations, Video, Color, Black&White, PublicDomain, CopyrightRestricted ...

https://phil.cdc.gov/AdvancedSearchResults.aspx?Search=Antigenic+Variation&parentid=26873&catid=3140

... provides important insights into the evolutionary mechanisms underpinning viral antigenic variations, and helps to understand ... Prediction of antigenic relationships among influenza viruses is useful for designing (or updating the existing) influenza ... In this study, we present a simple and physically interpretable model that can predict antigenic relationships among influenza ... Antigenic variations of influenza A viruses are induced by genomic mutation in their trans-membrane protein HA1, eliciting ...

https://www.nature.com/articles/s41598-019-46740-5?error=cookies_not_supported&code=e26a5516-8615-46ee-9eca-bda7d1c879eb

Norovirus; animal models; antigenic variation; bioengineering; capsid; children; clinical trials; coat proteins; elderly; ... spatial variation; spring; summer; temporal variation; toxicity; vinyl acetate; volatile organic compounds; winter; Taiwan. ... However, it is still unclear whether temperature variation within the same day, that is diurnal temperature range (DTR), is ... 5. Change in the efficacy of influenza vaccination after repeated inoculation under antigenic mismatch: A systematic review and ...

https://pubag.nal.usda.gov/?f%5Bpublication_year_rev_facet%5D%5B%5D=7982-2018&f%5Bsubject_facet%5D%5B%5D=elderly&f%5Bsubject_facet%5D%5B%5D=children&f%5Bsubject_term%5D%5B%5D=children&f%5Btext_availability_facet%5D%5B%5D=Citation+in+PubAg&per_page=100&search_field=author&sort=relevance

KEY WORDS: Computational biology; B-lymphocyte epitopes; Recombinant fusion proteins; Antigenic variation; Mycoplasma hominis ...

https://www.minervamedica.it/en/journals/gazzetta-medica-italiana/article.php?cod=R22Y2019N09A0654

Antigenic variation in Plasmodium falciparum:mechanisms and consequences. Curr Opin Microbiol 1999;2:420-5. [PUBMED] [FULLTEXT] ... mechanisms which include clonal antigenic variation and altered peptide ligand (APL) antagonism.[3] Despite extensive efforts ... Identification of conserved antigenic components for a cytotoxic T lymphocyte-inducing vaccine against malaria. Lancet 1995;345 ... persistence of malaria infections within populations is the ability of the parasites to undergo repeated antigenic variation.[2 ...

https://www.jpgmonline.com/article.asp?issn=0022-3859

Renibacterium salmoninarum p57 antigenic variation is restricted in geographic distribution and correlated with genomic markers ...

https://www.ars.usda.gov/research/publications/publications-at-this-location/?modecode=19-30-05-00&locpubs=yes&filterYear=2008

However, over time there may be enough antigenic variation (antigenic drift) within the same subtype that infection or ... Antigenic variation occurs with influenza B viruses, although no subtypes are known to exist. For these reasons, major ... Antigenic analysis of type A(H1N1) viruses from outbreaks indicates that most strains are closely related to the U.S. vaccine ... The antigenic characteristics of current strains provide the basis for selecting virus strains included in each years vaccine. ...

https://wonder.cdc.gov/wonder/prevguid/p0000270/p0000270.asp

This antigenic variation associated with the surface exposed PfEMP-1 allows the parasite to evade the immune system. However, ... For example, P. falciparum exhibits an antigenic variation that allows it to stay one step ahead of the immune system. In ... Click here for more on knobs, receptors/ligands, and antigenic variation.. Early observations of the pathology of cerebral ... This, along with antigenic variation and polymorphisms in many Plasmodium antigens, could explain the slow development of ...

http://www2.tulane.edu/~wiser/protozoology/notes/malaria.html

For example, antigenic variation may diminish the efficacy of antibodies, or affect T-cell recognition and memory. Changes in ... These changes include antigenic divergence with vaccine strains and increased production of pertussis toxin. Antigenic ... Characterization of the key antigenic components of pertussis vaccine based on outer membrane vesicles. Vaccine, Vol. 32, Issue ... Studies on prn variation in the mouse model and comparison with epidemiological data. PLoS One 2011; 6: e18014.CrossRefGoogle ...

https://www.cambridge.org/core/journals/epidemiology-and-infection/article/pertussis-resurgence-waning-immunity-and-pathogen-adaptation-two-sides-of-the-same-coin/2C4624385819C751F0C4E9448D4ABF04

ANTIGENIC VARIATION; TWITCHING MOTILITY; HUMAN SPERM; HUMAN-SEMEN; ATTACHMENT. Multiple languages. ...

https://kups.ub.uni-koeln.de/44394/

Plasmodium falciparum uses antigenic variation to evade host immunity, including vaccine-induced immunity.1,2 The protective ... They cannot measure antibody function, and seroreactivity to any one of the large number of antigenic variants on an array does ... array represents an enabling technology that will make it possible to evaluate antibody responses to large numbers of antigenic ...

https://www.ajtmh.org/view/journals/tpmd/92/1/article-p9.xml?rskey=SgXF2S&result=31

Antigenic characterization: Monitoring antigenic variation as the influenza season progresses is an important part of the ... including antiviral resistance and antigenic variation. Laboratories equipped to readily determine the genome sequence will be ... as viral isolates are required for antigenic characterization to monitor for potential antigenic drift and antiviral resistance ... Because the NML has the technical capacity for antigenic characterization and is required to conduct surveillance reporting to ...

https://www.canada.ca/en/public-health/services/flu-influenza/canadian-pandemic-influenza-preparedness-planning-guidance-health-sector/laboratory-annex.html

"Antigenic variation in malaria involves a highly structured switching pattern" 3:00 - 3:30 Tea & Coﬀee in the Mathematics ...

https://warwick.ac.uk/fac/sci/maths/research/events/2009_2010/symposium/eeewks/

Analysis of recent influenza A(H3N2) viruses indicates antigenic drift from the previously prevalent strains A/Mississippi/1/85 and A/Leningrad/360/86. (cdc.gov)
Antigenic variation among strains of the New Jersey serotype of vesicular stomatitis virus. (utmb.edu)
however, by plaque-reduction neutralization method, slight antigenic differences were observed between the Hazelhurst and the three other strains. (utmb.edu)
Dive into the research topics of 'Antigenic variation among strains of the New Jersey serotype of vesicular stomatitis virus. (utmb.edu)
Antigenic analysis of type A(H1N1) viruses from outbreaks indicates that most strains are closely related to the U.S. vaccine strain, A/Taiwan/1/86. (cdc.gov)
However, over time there may be enough antigenic variation (antigenic drift) within the same subtype that infection or vaccination with one strain may not induce immunity to distantly related strains of the same subtype. (cdc.gov)
The antigenic characteristics of current strains provide the basis for selecting virus strains included in each year's vaccine. (cdc.gov)
These changes include antigenic divergence with vaccine strains and increased production of pertussis toxin. (cambridge.org)
Because about 75 percent of Shigella infections in developing countries are caused by Shigella sonnei, the lack of antigenic variation within this species makes it difficult to discriminate between strains. (cdc.gov)
Understanding the amount of genetic variation and the relatedness of strains helps us appreciate the way the organism is changing and interpret our laboratory findings to track and control the spread of infections. (cdc.gov)
Recently isolated FMDV strains showed high genetic variations from locally used vaccine strains in the major antigenic sites of VP1 region. (mendeley.com)
Individual strains may show antigenic drift, presumably generating new serotypes over time. (creative-biolabs.com)
One is a phenomenon, especially associated with INFLUENZA VIRUSES , where they undergo spontaneous variation both as slow antigenic drift and sudden emergence of new strains (antigenic shift). (bvsalud.org)

Using the example of a model of antigenic variation in malaria, we show how many of the observed dynamical regimes can be explained in terms of the symmetry of interactions between different antigenic variants. (arxiv.org)
Stability and bifurcations in a model of antigenic variation in malaria. (ox.ac.uk)
We examine the properties of a recently proposed model for antigenic variation in malaria which incorporates multiple epitopes and both long-lasting and transient immune responses. (ox.ac.uk)
[1] An important reason for the persistence of malaria infections within populations is the ability of the parasites to undergo repeated antigenic variation. (jpgmonline.com)
[7] There is evidence of the suppression and evasion of parasite-specific responses during acute malaria: mechanisms which include clonal antigenic variation and altered peptide ligand (APL) antagonism. (jpgmonline.com)

Although antigenic variants differ in some epitopes on the hemagglutinin, they also share other common hemagglutinin epitopes. (cdc.gov)
The significant variations in the predicted epitopes showing high antigenicity were A348V, V367F and A419S in receptor binding domain (RBD). (thieme-connect.com)
Conclusion S protein is the major target for vaccine development, but several mutations were predicted in the antigenic epitopes of S protein across all genomes available globally. (thieme-connect.com)

It tracks the dynamics of all unique var repertoires in a population of hosts, and shows that even under high levels of sexual recombination, strain competition mediated through cross-immunity structures the parasite population into a subset of coexisting dominant repertoires of var genes whose degree of antigenic overlap depends on transmission intensity. (nih.gov)
This large variation is probably due to different definitions of immunity and different vaccines included in these studies. (cambridge.org)
Immunoglobulin gamma marker (GM) and kappa marker (KM) allotypes, hereditary antigenic determinants of gamma and kappa chains, respectively, have been shown to be associated with immunity to a variety of self and nonself antigens, but their possible contribution to immunity to the tumor-associated antigens epidermal growth factor receptor (EGFR) and EGFR variant (v)III has not been evaluated. (cdc.gov)

VEX1 controls the allelic exclusion required for antigenic variation in trypanosomes. (lshtm.ac.uk)
Allelic exclusion underpins antigenic variation and immune evasion in African trypanosomes. (lshtm.ac.uk)
Trypanosomes develop as extracellular parasites and escape the host immune response by means of a sophisticated process of antigenic variation. (biomedcentral.com)

The model explicitly considers the extensive diversity of multi-copy genes that undergo antigenic variation via sequential, mutually exclusive expression. (nih.gov)
Empirical comparison of patterns of genetic variation at antigenic and neutral sites supports this role for immune selection in structuring parasite diversity.DOI:http://dx.doi.org/10.7554/eLife.00093.001. (nih.gov)
The mosaic structure of the sequences and their division into subgroups may reflect the conflicting problems of maximizing antigenic diversity and minimizing epitope sharing between variants while maintaining their host cell binding functions. (ox.ac.uk)
Many of these glycoproteins show amino acid sequence diversity expressed as antigenic variations. (harvard.edu)
Each RVA genomic segment has extensive variability, which may reflect in antigenic diversity of the respective proteins, mainly VP7 and VP4 proteins that comprise the outer layer. (bvsalud.org)

Homologous recombination dominates as the major form of DNA repair in Trypanosoma brucei, and is especially important for recombination of the subtelomeric variant surface glycoprotein during antigenic variation. (archives-ouvertes.fr)
A yeast-endonuclease-generated DNA break induces antigenic switching in Trypanosoma brucei. (harvard.edu)

Plasmodium falciparum antigenic variation. (ox.ac.uk)

Editorial Note: In 1987, the World Health Organization Collaborating Centers for Influenza (Atlanta and London), in conjunction with National Influenza Centers in several countries in Asia and Oceania, detected antigenic variants of influenza A(H3N2). (cdc.gov)

Analysis of about 50 recently isolated A(H3N2) viruses from Asia, Oceania, and the United States indicates a spectrum of antigenic specificity, with many isolates having reaction patterns intermediate between A/Leningrad/360/86 and A/Sichuan/2/87. (cdc.gov)

The occurrence of viruses that exhibit antigenic drift from the vaccine strain has on occasion resulted in diminished vaccine efficacy, such as the failure of A/Port Chalmers/1/73 to protect against A/Victoria/3/75 (2). (cdc.gov)
In 1972, vaccine containing A/Aichi/2/68 reduced cases of influenza by 60% in an outbreak caused by the antigenic drift variant A/England/42/72 (3), and, in 1977, A/Victoria/3/75 vaccine protected adults from A/Texas/1/77 infection with 80% efficacy (4). (cdc.gov)
Significant protection from illness may also be induced by the neuraminidase surface glycoprotein (5,6), which has shown less evidence of antigenic drift. (cdc.gov)

This causes antigenic variation in infectious agents and a high interindividual variability in the human response to the vaccine. (scielo.br)

In addition, the antigenic changes described occurred in the hemagglutinin surface glycoprotein. (cdc.gov)

Still other factors, such as the capacity of a strain to spread in the population, can emerge independently from changes in the antigenic properties of the hemagglutinin. (cdc.gov)
Antigenic cartograph representative of hemagglutinin inhibition (HI) titers of canine influenza viruses, China, 2009-2017, showing antigenic groups A-C. Map was generated by using AntigenMap 3D ( http://sysbio.cvm.msstate.edu/software/AntigenMap ) and HI data shown in Table 2 . (cdc.gov)
Although repeated exposure to influenza H3 induced the so-called "original antigenic sin" phenomena in hemagglutination inhibition assay titers against exposure to viruses later on, the ferret antibodies showed gradually enhanced avidity for different H3/hemagglutinin. (infectiousdiseaseadvisor.com)

Antigenic variations of influenza A viruses are induced by genomic mutation in their trans-membrane protein HA1, eliciting viral escape from neutralization by antibodies generated in prior infections or vaccinations. (nature.com)
Prediction of antigenic relationships among influenza viruses is useful for designing (or updating the existing) influenza vaccines, provides important insights into the evolutionary mechanisms underpinning viral antigenic variations, and helps to understand viral epidemiology. (nature.com)
In this study, we present a simple and physically interpretable model that can predict antigenic relationships among influenza A viruses, based on biophysical ideas, using both genomic amino acid sequences and experimental antigenic data. (nature.com)
Prediction of antigenic relationships (similar or variant) among influenza viruses is useful in designing (or updating the existing) effective influenza vaccines, provides important insights into the evolutionary mechanisms that underpin their antigenic variations due to the pressure of natural selection imposed by the neutralizing antibodies 10 , and helps to understand the epidemiology of these pathogens. (nature.com)
Antigenic variation occurs with influenza B viruses, although no subtypes are known to exist. (cdc.gov)
Antigenic variation is displayed by a number of important pathogenic viruses. (creative-biolabs.com)
The extent of cross-reactive ferret antibodies induced by repeated exposure to influenza H3 also increased, and antigenic variations between influenza H3 viruses characterized by ferret antisera decreased as the number of exposures increased. (infectiousdiseaseadvisor.com)
This rise in antibody avidity inversely correlated with reduced antigenic differences among H3 viruses characterized. (infectiousdiseaseadvisor.com)

In the studies of dynamics of pathogens and their interactions with a host immune system, an important role is played by the structure of antigenic variants associated with a pathogen. (arxiv.org)
One of the many fascinating features of this unique pathogen is an elaborate system for antigenic variation, whereby the sequence of the surface-bound lipoprotein VlsE is continually modified through segmental gene conversion events. (jbc.org)
Antigenic variation as the pathogen passes through an entire host population rather than just a single host. (bvsalud.org)

The antigenic relationships of the human and swine IAV were investigated by hemagglutination inhibition (HI) assays using panels of post-infection ferret and swine antisera raised against representative human and swine IAV (see Appendix Table 1 and S2). (cdc.gov)

Shigella sonnei only has one antigenic variant we call a serotype, while the other Shigella species each have many serotypes which helps distinguish one strain from another within a species. (cdc.gov)
Interference among the three attenuated poliovirus serotypes was minimized with a 'balanced- formulation' vaccine, and serologic responses after IPV were optimized by adjusting the antigenic content of each inactivated poliovirus serotype. (who.int)

It is concluded that these antigenic differences are insufficient to warrant reclassification of vesicular stomatitis virus--New Jersey into two distinct subtypes, as has been recently proposed. (utmb.edu)
Differences in the antigenic makeup of meningococcal clonal complexes (cc) ( 11 ) likely influence reported disparities in spatiotemporal spread. (cdc.gov)
Nancy Strockbine] Shigella sonnei is one of four species of Shigella that are recognized for historical and medical reasons and are classified on the basis of biochemical and antigenic differences. (cdc.gov)

T. brucei sequentially expresses immunologically distinct Variant Surface Glycoproteins (VSGs), its major surface antigen, to evade the host's immune response, and Dr. Li's lab has demonstrated that telomeres play critical roles in regulating this antigenic variation process in T. brucei . (csuohio.edu)

Antigenic divergence will affect both memory recall and the efficacy of antibodies, while higher levels of pertussis toxin may increase suppression of the innate and acquired immune system. (cambridge.org)
Additionally, recent advances in immunogenetics and genomics should help in the understanding of the influence of genetic factors on the interindividual and interpopulation variations in immune responses to vaccines, and could be useful for developing new vaccine strategies. (scielo.br)
Among them are the direct and indirect suppression of host immune signals, phase and antigenic variation, escaping recognition by host complement proteins, and seclusion into immune privileged sites. (isbn.nu)

A primary basis of antigenic variation is a selection of virus mutants by antibodies. (creative-biolabs.com)

This response confirms the existence of antigenic variation in recent virus isolates. (cdc.gov)
Antigenic variation refers to the observation that different isolates of a single virus species may show variable cross-reactivity when tested with a standard serum. (creative-biolabs.com)

In addition, the geometric mean titers were higher to the homologous A/Leningrad/360/86 antigen than to the antigenic variants A/Sichuan/2/87 or A/Victoria/7/87. (cdc.gov)

Studies conducted in the Brazilian Mid-West have shown a temporal variation in the predominance of certain G and P genotypes, characterizing the occurrence of an antigenic shift (Cardoso et al. (bvsalud.org)

We conclude that MRN promotes stringent homologous recombination at subtelomeric loci and restrains antigenic variation. (archives-ouvertes.fr)
We describe two tandem repeat loci, designated 'TR6' and 'TR10', which display extensive sequence variation that may be useful for sequence-based strain typing. (biomedcentral.com)

Vaccinees in all age groups developed titers of 40 or more to A/Leningrad/360/86 with greater frequency than they did to the new antigenic variants (Table 2). (cdc.gov)

Genetics is the study of genes , heredity , and the variation of organisms , as well as the medical practice of diagnosing, treating, and counseling patients with genetic disorders . (wikipedia.org)

Vaccine development faces major difficulties partly because of genetic variation in both infectious organisms and humans. (scielo.br)

and National Institute for complicating interpretation of variation in fi m genes. (cdc.gov)

Efforts to estimate the prevalence of genetic variations underpinning the antigenic expression are emerging. (biorxiv.org)

The aim of the present investigation was to determine whether the interindividual variation in endogenous antibody responsiveness to EGFR and EGFRvIII is associated with particular GM, KM, and Fcgamma receptor (FcgammaR) genotypes and whether antibody levels were associated with the overall survival of patients with glioblastoma. (cdc.gov)

The variation may be manifest in different ways depending on the virus' natural biology. (creative-biolabs.com)

The formulation of the vaccine is reviewed annually to take account of the antigenic variation of the virus. (alcohol.gov.au)

Eastern) are not subject to significant antigenic variation. (who.int)

A spatially slowly moving clone with multiple-locus variable-number tandem repeat analysis type 19, ST42, and antigenic profile B:P1.7-2,4:F1-5 was responsible for the outbreak. (cdc.gov)
A review of surveys conducted to date reveals considerable variation in both the choice and use of survey methods and in the assumptions made in the analysis and interpretation of findings. (who.int)

I'm interested in how telomere-binding proteins define the chromatin structure at the chromosome ends and how they influence antigenic variation. (uni-wuerzburg.de)

Anatomy5

Organisms28

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Chemicals and Drugs26

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Phenomena and Processes35

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Health Care1

Genetic and antigenic variation of capsid protein VP7 of serotype G1 human rotavirus isolates. (1/863)

The major immunogenic epitopes of Epstein-Barr virus (EBV) nuclear antigen 1 are encoded by sequence domains which vary among nasopharyngeal carcinoma biopsies and EBV-associated cell lines. (2/863)

Antigenic variation in malaria: a 3' genomic alteration associated with the expression of a P. knowlesi variant antigen. (3/863)

Phase variations of the Mycoplasma penetrans main surface lipoprotein increase antigenic diversity. (4/863)

Molecular and functional analysis of a conserved CTL epitope in HIV-1 p24 recognized from a long-term nonprogressor: constraints on immune escape associated with targeting a sequence essential for viral replication. (5/863)

Spontaneous regression of primary autoreactivity during chronic progression of experimental autoimmune encephalomyelitis and multiple sclerosis. (6/863)

Antigenic heterogeneity of the hepatitis C virus NS4 protein as modeled with synthetic peptides. (7/863)

Structural and evolutionary inference from molecular variation in Neisseria porins. (8/863)

Antigenic Variation

Genetic Variation

Variant Surface Glycoproteins, Trypanosoma

Genes, Protozoan

Trypanosoma brucei brucei

Trypanosoma

Antigens, Bacterial

Molecular Sequence Data

Protozoan Proteins

Babesia bovis

Antigens, Protozoan

Fimbriae Proteins

Neisseria gonorrhoeae

Borrelia

Trypanosomiasis

Epitopes

Antigens, Viral

Amino Acid Sequence

Bacterial Outer Membrane Proteins

Plasmodium falciparum

Recombination, Genetic

Host-Parasite Interactions

Base Sequence

Giardia lamblia

Trypanosoma brucei gambiense

Sequence Analysis, DNA

Bacterial Proteins

Trypanosomiasis, African

Giardiasis

Relapsing Fever

Immune Evasion

Antigens, Surface

Anaplasma

Genome, Protozoan

RNA, Protozoan

DNA, Protozoan

Antibodies, Monoclonal

Phylogeny

Cross Reactions

Campylobacter fetus

Neutralization Tests

Serotyping

Species Specificity

Gene Conversion

Aphthovirus

DNA, Bacterial

Multigene Family

Malaria, Falciparum

Fimbriae, Bacterial

Telomere

Hemagglutination Inhibition Tests

Mycoplasma

Equine Infectious Anemia

Orthomyxoviridae

Antibodies, Bacterial

Lipoproteins

Lyme Disease

Borrelia burgdorferi

Antibodies, Viral

Genes, Bacterial

Gene Silencing

Agglutination Tests

Repetitive Sequences, Nucleic Acid

Mycoplasma genitalium

Hemagglutinins, Viral

Phenotype

Immune Sera

Sequence Homology, Amino Acid

Sequence Alignment

Immunodominant Epitopes

Erythrocytes

Influenza A virus

Antibodies, Protozoan

Spirochaetales

Giardia

Cloning, Molecular

Radioimmunoprecipitation Assay

Plasmodium

Anaplasma marginale

Anaplasmosis