• Findings from his research include the transporter molecule responsible for P. falciparum chloroquine resistance (PfCRT), the molecules responsible for antigenic variation and immune evasion by P. falciparum (var genes), a mechanism for sickle-cell trait protection against malaria, and the PfHRP-II protein used for malaria rapid diagnostic tests (RDTs). (nih.gov)
  • These investigations have focused on identifying the mechanistic determinants responsible for antigenic variation, and genetic factors involved in host adaptation and pathogenesis. (bankheadlab.org)
  • Types distinguished by antigenic differences in matrix and nucleoprotein antigens. (powershow.com)
  • Antigenic map is an analog of geographic cartography in presenting the comparing antigens onto two or three dimensional map. (hekademeia.org)
  • Studies on antigenic diversity in the malaria S-antigens / by Nina Gloriana-Barzaga. (who.int)
  • ATIVS is a webserver for analyzing serological data of all influenza viruses and hemagglutinin sequence data of human influenza A/H3N2 viruses so as to generate antigenic maps for influenza surveillance and vaccine strain selection. (hekademeia.org)
  • There is little information on their evolution in Jordan so this study investigated the genetic and antigenic variability of A(H1N1)pdm09 and H3N2 viruses in Jordan by performing phylogenetic and genetic analyses of the HA and NA genes of A(H1N1)pdm09 and H3N2 viruses between 2011 and 2013. (who.int)
  • Jordanian H1N1 viruses had mutations that are characteristic of antigenic group 6 while H3N2 virus mutations belonged to group 3. (who.int)
  • Peu de renseignements sont disponibles sur les mutations des virus saisonniers de la grippe A(H1N1)pdm09 et H3N2 en Jordanie. (who.int)
  • Afin de remédier à ce problème et d'étudier les variations génétiques et antigéniques des virus A(H1N1)pdm09 et H3N2, nous avons procédé à des analyses génétiques et phylogénétiques des gènes de l'hémagglutinine (HA) et de la neuraminidase (NA) de ces virus, sur la période 2011-2013 en Jordanie. (who.int)
  • In predominant GII.4 strains, genetic changes are most prevalent in continuously evolving areas of the capsid P2 domain and correlate with antigenic changes. (unc.edu)
  • Chapter 3 characterizes antigenic changes between two successive GII.4 strains, GII.4-2009 New Orleans and GII.4-2012 Sydney. (unc.edu)
  • These GII.4 norovirus studies have allowed us to identify major determinants of antigenic change in GII.4 noroviruses that will allow for rapid diagnostic identification of new epidemic strains and direct the rational development of norovirus therapeutics and vaccines. (unc.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)
  • Waning of vaccine-induced immunity plays a role, but antigenic differences between vaccine and mumps outbreak strains could also contribute to reduced vaccine effectiveness. (mdpi.com)
  • 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)
  • Antigenic variation can be either antigenic drift from accumulating mutations or antigenic shift from exchanging surface proteins from two different strains. (hekademeia.org)
  • This pattern is the result of antigenic variation in spirochete outer surface proteins, temporarily evading the host immune response and allowing spirochete numbers to rebound ( 5 ). (cdc.gov)
  • The major goal of my study is to elucidate the molecular details of the highly efficient antigenic variation system of the spirochete that is responsible for its spectacular persistence during infection of the mammalian host. (bankheadlab.org)
  • In this study, we have identified and characterized an elaborate genetic system in the Lyme disease spirochete B. burgdorferi that promotes extensive antigenic variation of a 34-kDa surface-exposed lipoprotein, VlsE. (uth.edu)
  • In the bacterium Borrelia burgdorferi, the cause of Lyme disease, the surface lipoprotein VlsE can undergo recombination which results in antigenic diversity. (wikipedia.org)
  • 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. (psu.edu)
  • The rifins exhibit considerable sequence diversity and may play an important role in antigenic variation. (jcvi.org)
  • Studies of population genetics have also created opportunities for strain identification and molecular taxonomy and for exploring the relationship between genetic diversity and properties of medical relevance such as virulence, resistance to drugs, antigenic variation, susceptibility to potential vaccines, and host and vector specificity. (bio.net)
  • Many of these glycoproteins show amino acid sequence diversity expressed as antigenic variations. (bvsalud.org)
  • Antigenic variation or antigenic alteration refers to the mechanism by which an infectious agent such as a protozoan, bacterium or virus alters the proteins or carbohydrates on its surface and thus avoids a host immune response, making it one of the mechanisms of antigenic escape. (wikipedia.org)
  • Antigenic variation can occur by altering a variety of surface molecules including proteins and carbohydrates. (wikipedia.org)
  • Many of the proteins known to show antigenic or phase variation are related to virulence. (wikipedia.org)
  • Giardia lamblia encodes several families of cysteine-rich proteins, including the Variant-specific Surface Proteins (VSPs) involved in the process of antigenic variation. (ucc.edu.ar)
  • Antigenic variation within dengue virus serotypes, and an mRNA vaccine that induces antibodies against tick proteins and prevents transmission of the Lyme disease agent. (asm.org)
  • During growth in the mammalian host the parasite undergoes the phenomenon of antigenic variation in order to escape the immune system of the host. (gla.ac.uk)
  • Neisseria gonorrhoeae lipooligosaccharide (LOS) undergoes antigenic variation at a high rate, and this variation can be monitored by changes in a strain's ability to bind LOS-specific monoclonal antibodies. (uky.edu)
  • Influenza virus undergoes antigenic variation, necessitating annual production of a new vaccine. (virology.ws)
  • One factor complicating vaccine and therapeutic design for noroviruses is antigenic variation in GII.4 norovirus, which account for over 70% of all outbreaks. (unc.edu)
  • Therefore, WHO now reviews the available antigenic and genetic data on animal and human H5N1 viruses in addition to the analyses of seasonal vaccine stains and has developed and made H5N1 candidate vaccine viruses available to vaccine producers so they can work on developing safe and effective human H5N1 vaccines for potential productioni. (who.int)
  • The antigenic components of the influenza vaccine have been updated for the 2007-2008 season. (canada.ca)
  • Antigenic map has been shown to effectively detect antigenic drift events, thus it is useful in antigenic characterization and vaccine strain selection. (hekademeia.org)
  • Antigenic variation occurs with influenza B viruses, although no subtypes are known to exist. (cdc.gov)
  • Although influenza B viruses have shown more antigenic stability than influenza A viruses, antigenic variation does occur. (canada.ca)
  • information on influenza viruses and to provide the infrastructure for experts to examine all relevant antigenic, virological and immunological data. (who.int)
  • 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)
  • The results suggest that within a serotype of FMDV, antigenically highly divergent viruses can arise in the field by very limited sequence variation at exposed key residues of each of several antigenic sites. (ox.ac.uk)
  • Therefore, effectively designed therapeutics and vaccines must be broadly active or easily reformulated to account for the antigenic properties of emergent viruses. (unc.edu)
  • Together, this network processes an estimated 150,000 to 200,000 respiratory specimens per year with approximately 5000 viruses voluntarily shared by the NICs undergoing extensive antigenic and genetic characterization among the WHO CCs. (who.int)
  • In Chapter 4, we investigate the antigenic change that occurs within an individual chronically infected with norovirus over time, map the varying epitopes and compare the degree of change with population-wide changes. (unc.edu)
  • Differences in antigenicity are due to a very limited number of substitutions of surface amino acids accessible to antibodies and located within antigenic sites previously identified on FMDV. (ox.ac.uk)
  • Depending on the variants compared, replacements within site A or at site D, or at both sites, contributed significantly to their antigenic differences. (ox.ac.uk)
  • 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)
  • 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). (microbiologyresearch.org)
  • Our results indicated that temporal genetic variation of the VP7 of serotype G1 rotaviruses was associated with changes in the antigenicity of these isolates. (microbiologyresearch.org)
  • Antigenic heterogeneity of a foot-and-mouth disease virus serotype in the field is mediated by very limited sequence variation at several antigenic sites. (ox.ac.uk)
  • Antigenic variation in a major discontinuous site (site D) of foot-and-mouth disease virus (FMDV) of serotype C has been evaluated with neutralizing monoclonal antibodies. (ox.ac.uk)
  • Antigenic variation of foot-and-mouth disease virus of serotype C during propagation in the field is mainly restricted to only one structural protein (VP1). (irsicaixa.es)
  • 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)
  • VSGs are important virulence factors because their switching allows trypanosomes to escape the host immune system, a mechanism known as antigenic variation. (asm.org)
  • The structure and sequence of the silent vls cassette locus is preserved during the process of the VlsE antigenic variation, consistent with a nonreciprocal recombination mechanism. (uth.edu)
  • Segments of the 15 non-expressed (silent) vls cassette sequences located upstream of vlsE are able to recombine into the central vlsE cassette region during infection of C3H/HeN mice, resulting in antigenic variation of the expressed lipoprotein. (uth.edu)
  • However, no recombination was detected during the period of 28-day in vitro culture, suggesting in vivo induction of VlsE antigenic variation. (uth.edu)
  • The 5' and 3' noncassette regions of vlsE are apparently not subject to recombination and sequence variation. (uth.edu)
  • This combinatorial form of antigenic variation could potentially yield millions of VlsE variants in the mammalian host, and thereby contribute to immune evasion, long-term survival, and pathogenesis of B. burgdorferi. (uth.edu)
  • These observations provide new insight on antigenic variation by showing that chromatin remodeling is an intrinsic feature of BES regulation. (asm.org)
  • Hemagglutination inhibition (HI), microneutralization (MN), and Enzyme-linked immunosorbent (ELISA) assays are three commonly used techniques for antigenic variation characterization. (hekademeia.org)
  • Pathogens often persist during infection because of antigenic variation in which they evade immunity by switching between distinct surface antigen variants. (ox.ac.uk)
  • Les mutations individuelles sont décrites en détail. (who.int)
  • Antigenic variation not only enables the pathogen to avoid the immune response in its current host, but also allows re-infection of previously infected hosts. (wikipedia.org)
  • The influence of antigenic variation on cytotoxic T lymphocyte responses in HIV-1 infection. (ox.ac.uk)
  • The propensity of HIV-1 for genetic variation, a consequence of error-prone reverse transcription combined with high rates of replication, is thought to contribute to the establishment of persistent infection in the host despite the presence of a vigorous antiviral immune response. (ox.ac.uk)
  • Plasmodium falciparum antigenic variation. (psu.edu)
  • Dive into the research topics of 'Plasmodium falciparum antigenic variation. (psu.edu)
  • Parasite-intrinsic factors can explain ordered progression of trypanosome antigenic variation. (ox.ac.uk)
  • This protozoan parasite evades the host immune system by antigenic variation, a periodic switching of its variant surface glycoprotein (VSG) coat. (nih.gov)
  • Fourier analysis of T-cell antigenic peptides indicates a periodic variation in amino acid polarities of 3-3.6 residues per period, suggesting an amphipathic α-helical structure. (huji.ac.il)
  • In the case of the dr(a-) phenotype, a single nucleotide substitution within exon 5 accounts for two changes: a simple amino acid substitution that is the basis of the antigenic variation, and an alternative splicing event that underlies the decreased expression of daf in this phenotype. (lu.se)
  • Antigenic variation is employed by a number of different protozoan parasites. (wikipedia.org)
  • AntigenMap is an online resource developed specifically for antigenic cartography construction using the data from immunological experiments, such as hemagglutination inhibition, microneutralization, and Enzyme-linked immunosorbent (ELISA) assays. (hekademeia.org)
  • Antigenic variation can result from gene conversion, site-specific DNA inversions, hypermutation, or recombination of sequence cassettes. (wikipedia.org)
  • Our work aims to define the mechanisms that drive genetic changes leading to antigenic changes in GII.4 noroviruses. (unc.edu)
  • My current project focuses on characterizing the mechanisms of antigenic variation by Borrelia hermsii in order to gain insight into how the relapsing fever pathogen persists inside the host despite immune responses. (bankheadlab.org)
  • L'analyse a porté sur les séquences complètes des gènes de l'HA et de la NA de 16 échantillons positifs au virus H1N1 prélevés dans le cadre de cette étude, ainsi que sur 21 séquences publiées de l'HA et 20 séquences publiées de la NA, issues de virus jordaniens disponibles sur les bases de données de gènes en ligne. (who.int)
  • AntigenMap provides users a choice to construct antigenic cartography in either 2D or 3D format. (hekademeia.org)
  • 2012. AntigenMap 3D: an online antigenic cartography resource. (hekademeia.org)
  • First, an analysis of haplotype-dependent peptide motifs indicates that the locations of their defining residues tend to force a period 3-4 variation in hydrophobicity along the peptide sequence, in a manner consistent with the spacing of pockets in the MHC. (huji.ac.il)
  • Antigenic variation is a common strategy for an infectious pathogen to evade its host immunological response. (hekademeia.org)
  • The variations in the number of persons who receive the mumps vaccination worldwide make it difficult to estimate the numbers affected. (medscape.com)
  • Host-adaptive antigenic variation in Bunyaviruses. (ox.ac.uk)
  • Extensive variation, comparable to that of continuous epitopes within the hypervariable immunodominant site A (the VP1 G-H loop), was found. (ox.ac.uk)
  • The temporal model was shown to be especially useful for antigenic map construction for the immunological datasets spanning a long time period. (hekademeia.org)
  • 3D display of antigenic cartography data allows for higher accuracy, especially when combined with the temporal model. (hekademeia.org)
  • We present an analysis that synthesizes information on the sequence, structure, and motifs of antigenic peptides, which previously appeared to be in conflict. (huji.ac.il)
  • A 28-kilobase linear plasmid of B. burgdorferi B31 (lp28-1) was found to contain a vmp-like sequence (vls) locus that closely resembles the variable major protein (vmp) system for antigenic variation of relapsing fever organisms. (uth.edu)
  • These results provide a sound physical chemical and structural basis for the existence of a haplotype-independent antigenic motif which can be particularly important in limiting the search time for antigenic peptides. (huji.ac.il)
  • The EMA family does not fit the paradigm for classical antigenic variation, and we propose a novel model describing the role of the EMA family in persistence. (biomedcentral.com)