Epitopes: Sites on an antigen that interact with specific antibodies.Epitopes, T-Lymphocyte: Antigenic determinants recognized and bound by the T-cell receptor. Epitopes recognized by the T-cell receptor are often located in the inner, unexposed side of the antigen, and become accessible to the T-cell receptors after proteolytic processing of the antigen.Epitopes, B-Lymphocyte: Antigenic determinants recognized and bound by the B-cell receptor. Epitopes recognized by the B-cell receptor are located on the surface of the antigen.Immunodominant Epitopes: Subunits of the antigenic determinant that are most easily recognized by the immune system and thus most influence the specificity of the induced antibody.Antibodies, Monoclonal: Antibodies produced by a single clone of cells.Amino Acid Sequence: 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.Molecular Sequence Data: 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.Cross Reactions: Serological reactions in which an antiserum against one antigen reacts with a non-identical but closely related antigen.Antibody Specificity: 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.T-Lymphocytes, Cytotoxic: Immunized T-lymphocytes which can directly destroy appropriate target cells. These cytotoxic lymphocytes may be generated in vitro in mixed lymphocyte cultures (MLC), in vivo during a graft-versus-host (GVH) reaction, or after immunization with an allograft, tumor cell or virally transformed or chemically modified target cell. The lytic phenomenon is sometimes referred to as cell-mediated lympholysis (CML). These CD8-positive cells are distinct from NATURAL KILLER CELLS and NATURAL KILLER T-CELLS. There are two effector phenotypes: TC1 and TC2.Peptide Fragments: Partial proteins formed by partial hydrolysis of complete proteins or generated through PROTEIN ENGINEERING techniques.Neutralization Tests: 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).Enzyme-Linked Immunosorbent Assay: 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.Peptides: Members of the class of compounds composed of AMINO ACIDS joined together by peptide bonds between adjacent amino acids into linear, branched or cyclical structures. OLIGOPEPTIDES are composed of approximately 2-12 amino acids. Polypeptides are composed of approximately 13 or more amino acids. PROTEINS are linear polypeptides that are normally synthesized on RIBOSOMES.HLA-A2 Antigen: A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*02 allele family.Antigens, Viral: Substances elaborated by viruses that have antigenic activity.HLA-A Antigens: Polymorphic class I human histocompatibility (HLA) surface antigens present on almost all nucleated cells. At least 20 antigens have been identified which are encoded by the A locus of multiple alleles on chromosome 6. They serve as targets for T-cell cytolytic responses and are involved with acceptance or rejection of tissue/organ grafts.Mice, Inbred BALB CAntigen Presentation: The process by which antigen is presented to lymphocytes in a form they can recognize. This is performed by antigen presenting cells (APCs). Some antigens require processing before they can be recognized. Antigen processing consists of ingestion and partial digestion of the antigen by the APC, followed by presentation of fragments on the cell surface. (From Rosen et al., Dictionary of Immunology, 1989)CD8-Positive T-Lymphocytes: A critical subpopulation of regulatory T-lymphocytes involved in MHC Class I-restricted interactions. They include both cytotoxic T-lymphocytes (T-LYMPHOCYTES, CYTOTOXIC) and CD8+ suppressor T-lymphocytes.Antibodies, Viral: Immunoglobulins produced in response to VIRAL ANTIGENS.Antigens, Bacterial: Substances elaborated by bacteria that have antigenic activity.Binding Sites, Antibody: Local surface sites on antibodies which react with antigen determinant sites on antigens (EPITOPES.) They are formed from parts of the variable regions of FAB FRAGMENTS.Antibodies, Neutralizing: Antibodies that reduce or abolish some biological activity of a soluble antigen or infectious agent, usually a virus.Autoantigens: Endogenous tissue constituents that have the ability to interact with AUTOANTIBODIES and cause an immune response.Immunization: Deliberate stimulation of the host's immune response. ACTIVE IMMUNIZATION involves administration of ANTIGENS or IMMUNOLOGIC ADJUVANTS. PASSIVE IMMUNIZATION involves administration of IMMUNE SERA or LYMPHOCYTES or their extracts (e.g., transfer factor, immune RNA) or transplantation of immunocompetent cell producing tissue (thymus or bone marrow).Peptide Library: A collection of cloned peptides, or chemically synthesized peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide.Autoantibodies: Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.Viral Envelope Proteins: 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.Immunoglobulin G: The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.T-Lymphocytes: Lymphocytes responsible for cell-mediated immunity. Two types have been identified - cytotoxic (T-LYMPHOCYTES, CYTOTOXIC) and helper T-lymphocytes (T-LYMPHOCYTES, HELPER-INDUCER). They are formed when lymphocytes circulate through the THYMUS GLAND and differentiate to thymocytes. When exposed to an antigen, they divide rapidly and produce large numbers of new T cells sensitized to that antigen.Vaccines, Synthetic: Small synthetic peptides that mimic surface antigens of pathogens and are immunogenic, or vaccines manufactured with the aid of recombinant DNA techniques. The latter vaccines may also be whole viruses whose nucleic acids have been modified.Histocompatibility Antigens Class I: Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.HIV-1: The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.CD4-Positive T-Lymphocytes: A critical subpopulation of T-lymphocytes involved in the induction of most immunological functions. The HIV virus has selective tropism for the T4 cell which expresses the CD4 phenotypic marker, a receptor for HIV. In fact, the key element in the profound immunosuppression seen in HIV infection is the depletion of this subset of T-lymphocytes.Hybridomas: Cells artificially created by fusion of activated lymphocytes with neoplastic cells. The resulting hybrid cells are cloned and produce pure MONOCLONAL ANTIBODIES or T-cell products, identical to those produced by the immunologically competent parent cell.HIV Antibodies: Antibodies reactive with HIV ANTIGENS.Cell Line: Established cell cultures that have the potential to propagate indefinitely.Protein Conformation: The characteristic 3-dimensional shape of a protein, including the secondary, supersecondary (motifs), tertiary (domains) and quaternary structure of the peptide chain. PROTEIN STRUCTURE, QUATERNARY describes the conformation assumed by multimeric proteins (aggregates of more than one polypeptide chain).Capsid Proteins: Proteins that form the CAPSID of VIRUSES.Recombinant Proteins: Proteins prepared by recombinant DNA technology.HLA-B7 Antigen: A specific HLA-B surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-B*07 allele family.HLA-A3 Antigen: A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*03 allele family.Lymphocyte Activation: Morphologic alteration of small B LYMPHOCYTES or T LYMPHOCYTES in culture into large blast-like cells able to synthesize DNA and RNA and to divide mitotically. It is induced by INTERLEUKINS; MITOGENS such as PHYTOHEMAGGLUTININS, and by specific ANTIGENS. It may also occur in vivo as in GRAFT REJECTION.Antigenic Variation: 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)Antigens, Neoplasm: Proteins, glycoprotein, or lipoprotein moieties on surfaces of tumor cells that are usually identified by monoclonal antibodies. Many of these are of either embryonic or viral origin.Antibodies, Bacterial: Immunoglobulins produced in a response to BACTERIAL ANTIGENS.Antibody Affinity: A measure of the binding strength between antibody and a simple hapten or antigen determinant. It depends on the closeness of stereochemical fit between antibody combining sites and antigen determinants, on the size of the area of contact between them, and on the distribution of charged and hydrophobic groups. It includes the concept of "avidity," which refers to the strength of the antigen-antibody bond after formation of reversible complexes.Binding, Competitive: The interaction of two or more substrates or ligands with the same binding site. The displacement of one by the other is used in quantitative and selective affinity measurements.Antigens, Protozoan: Any part or derivative of any protozoan that elicits immunity; malaria (Plasmodium) and trypanosome antigens are presently the most frequently encountered.HIV Antigens: Antigens associated with specific proteins of the human adult T-cell immunodeficiency virus (HIV); also called HTLV-III-associated and lymphadenopathy-associated virus (LAV) antigens.Recombinant Fusion Proteins: Recombinant proteins produced by the GENETIC TRANSLATION of fused genes formed by the combination of NUCLEIC ACID REGULATORY SEQUENCES of one or more genes with the protein coding sequences of one or more genes.Viral Vaccines: Suspensions of attenuated or killed viruses administered for the prevention or treatment of infectious viral disease.HLA-DR Antigens: A subclass of HLA-D antigens that consist of alpha and beta chains. The inheritance of HLA-DR antigens differs from that of the HLA-DQ ANTIGENS and HLA-DP ANTIGENS.HLA-B Antigens: Class I human histocompatibility (HLA) surface antigens encoded by more than 30 detectable alleles on locus B of the HLA complex, the most polymorphic of all the HLA specificities. Several of these antigens (e.g., HLA-B27, -B7, -B8) are strongly associated with predisposition to rheumatoid and other autoimmune disorders. Like other class I HLA determinants, they are involved in the cellular immune reactivity of cytolytic T lymphocytes.Molecular Mimicry: The structure of one molecule that imitates or simulates the structure of a different molecule.HIV Envelope Protein gp120: External envelope protein of the human immunodeficiency virus which is encoded by the HIV env gene. It has a molecular weight of 120 kDa and contains numerous glycosylation sites. Gp120 binds to cells expressing CD4 cell-surface antigens, most notably T4-lymphocytes and monocytes/macrophages. Gp120 has been shown to interfere with the normal function of CD4 and is at least partly responsible for the cytopathic effect of HIV.Antibodies: Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).Vaccines, DNA: Recombinant DNA vectors encoding antigens administered for the prevention or treatment of disease. The host cells take up the DNA, express the antigen, and present it to the immune system in a manner similar to that which would occur during natural infection. This induces humoral and cellular immune responses against the encoded antigens. The vector is called naked DNA because there is no need for complex formulations or delivery agents; the plasmid is injected in saline or other buffers.AIDS Vaccines: Vaccines or candidate vaccines containing inactivated HIV or some of its component antigens and designed to prevent or treat AIDS. Some vaccines containing antigens are recombinantly produced.Immune Sera: 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.Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.Bacterial Outer Membrane Proteins: Proteins isolated from the outer membrane of Gram-negative bacteria.Base Sequence: The sequence of PURINES and PYRIMIDINES in nucleic acids and polynucleotides. It is also called nucleotide sequence.Interferon-gamma: The major interferon produced by mitogenically or antigenically stimulated LYMPHOCYTES. It is structurally different from TYPE I INTERFERON and its major activity is immunoregulation. It has been implicated in the expression of CLASS II HISTOCOMPATIBILITY ANTIGENS in cells that do not normally produce them, leading to AUTOIMMUNE DISEASES.H-2 Antigens: The major group of transplantation antigens in the mouse.Mice, Inbred C57BLCapsid: The outer protein protective shell of a virus, which protects the viral nucleic acid.Rabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Models, Molecular: Models used experimentally or theoretically to study molecular shape, electronic properties, or interactions; includes analogous molecules, computer-generated graphics, and mechanical structures.B-Lymphocytes: Lymphoid cells concerned with humoral immunity. They are short-lived cells resembling bursa-derived lymphocytes of birds in their production of immunoglobulin upon appropriate stimulation.Antigen-Antibody Reactions: The processes triggered by interactions of ANTIBODIES with their ANTIGENS.HLA Antigens: Antigens determined by leukocyte loci found on chromosome 6, the major histocompatibility loci in humans. They are polypeptides or glycoproteins found on most nucleated cells and platelets, determine tissue types for transplantation, and are associated with certain diseases.Species Specificity: 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.HLA-A24 Antigen: A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*24 allele family.Clone Cells: A group of genetically identical cells all descended from a single common ancestral cell by mitosis in eukaryotes or by binary fission in prokaryotes. Clone cells also include populations of recombinant DNA molecules all carrying the same inserted sequence. (From King & Stansfield, Dictionary of Genetics, 4th ed)Histocompatibility Antigens Class II: Large, transmembrane, non-covalently linked glycoproteins (alpha and beta). Both chains can be polymorphic although there is more structural variation in the beta chains. The class II antigens in humans are called HLA-D ANTIGENS and are coded by a gene on chromosome 6. In mice, two genes named IA and IE on chromosome 17 code for the H-2 antigens. The antigens are found on B-lymphocytes, macrophages, epidermal cells, and sperm and are thought to mediate the competence of and cellular cooperation in the immune response. The term IA antigens used to refer only to the proteins encoded by the IA genes in the mouse, but is now used as a generic term for any class II histocompatibility antigen.HLA-A11 Antigen: A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*11 allele family.Cytotoxicity, Immunologic: The phenomenon of target cell destruction by immunologically active effector cells. It may be brought about directly by sensitized T-lymphocytes or by lymphoid or myeloid "killer" cells, or it may be mediated by cytotoxic antibody, cytotoxic factor released by lymphoid cells, or complement.Allergens: Antigen-type substances that produce immediate hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).T-Lymphocytes, Helper-Inducer: Subpopulation of CD4+ lymphocytes that cooperate with other lymphocytes (either T or B) to initiate a variety of immune functions. For example, helper-inducer T-cells cooperate with B-cells to produce antibodies to thymus-dependent antigens and with other subpopulations of T-cells to initiate a variety of cell-mediated immune functions.Antigens, Surface: 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.Antigens, Plant: Substances found in PLANTS that have antigenic activity.Protozoan Proteins: Proteins found in any species of protozoan.Viral Proteins: Proteins found in any species of virus.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Immunoblotting: Immunologic method used for detecting or quantifying immunoreactive substances. The substance is identified by first immobilizing it by blotting onto a membrane and then tagging it with labeled antibodies.Vaccines, Subunit: Vaccines consisting of one or more antigens that stimulate a strong immune response. They are purified from microorganisms or produced by recombinant DNA techniques, or they can be chemically synthesized peptides.Blotting, Western: Identification of proteins or peptides that have been electrophoretically separated by blot transferring from the electrophoresis gel to strips of nitrocellulose paper, followed by labeling with antibody probes.HLA-B35 Antigen: A specific HLA-B surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-B*35 allele family.Antibody Formation: The production of ANTIBODIES by proliferating and differentiated B-LYMPHOCYTES under stimulation by ANTIGENS.Antigen-Antibody Complex: The complex formed by the binding of antigen and antibody molecules. The deposition of large antigen-antibody complexes leading to tissue damage causes IMMUNE COMPLEX DISEASES.env Gene Products, Human Immunodeficiency Virus: Proteins encoded by the ENV GENE of the HUMAN IMMUNODEFICIENCY VIRUS.Cancer Vaccines: Vaccines or candidate vaccines designed to prevent or treat cancer. Vaccines are produced using the patient's own whole tumor cells as the source of antigens, or using tumor-specific antigens, often recombinantly produced.Bacterial Proteins: Proteins found in any species of bacterium.Sequence Homology, Amino Acid: The degree of similarity between sequences of amino acids. This information is useful for the analyzing genetic relatedness of proteins and species.Protein Structure, Tertiary: The level of protein structure in which combinations of secondary protein structures (alpha helices, beta sheets, loop regions, and motifs) pack together to form folded shapes called domains. Disulfide bridges between cysteines in two different parts of the polypeptide chain along with other interactions between the chains play a role in the formation and stabilization of tertiary structure. Small proteins usually consist of only one domain but larger proteins may contain a number of domains connected by segments of polypeptide chain which lack regular secondary structure.Vaccination: Administration of vaccines to stimulate the host's immune response. This includes any preparation intended for active immunological prophylaxis.Mice, Transgenic: Laboratory mice that have been produced from a genetically manipulated EGG or EMBRYO, MAMMALIAN.HIV Envelope Protein gp41: Transmembrane envelope protein of the HUMAN IMMUNODEFICIENCY VIRUS which is encoded by the HIV env gene. It has a molecular weight of 41,000 and is glycosylated. The N-terminal part of gp41 is thought to be involved in CELL FUSION with the CD4 ANTIGENS of T4 LYMPHOCYTES, leading to syncytial formation. Gp41 is one of the most common HIV antigens detected by IMMUNOBLOTTING.Vaccinia virus: The type species of ORTHOPOXVIRUS, related to COWPOX VIRUS, but whose true origin is unknown. It has been used as a live vaccine against SMALLPOX. It is also used as a vector for inserting foreign DNA into animals. Rabbitpox virus is a subspecies of VACCINIA VIRUS.Oligopeptides: Peptides composed of between two and twelve amino acids.Binding Sites: The parts of a macromolecule that directly participate in its specific combination with another molecule.Gliadin: Simple protein, one of the prolamines, derived from the gluten of wheat, rye, etc. May be separated into 4 discrete electrophoretic fractions. It is the toxic factor associated with CELIAC DISEASE.Gene Products, gag: Proteins coded by the retroviral gag gene. The products are usually synthesized as protein precursors or POLYPROTEINS, which are then cleaved by viral proteases to yield the final products. Many of the final products are associated with the nucleoprotein core of the virion. gag is short for group-specific antigen.Enzyme-Linked Immunospot Assay: A method of detection of the number of cells in a sample secreting a specific molecule. With this method, a population of cells are plated over top of the immunosorbent substrate that captures the secreted molecules.Sequence Alignment: 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.Conserved Sequence: 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.HLA-DQ Antigens: A group of the D-related HLA antigens found to differ from the DR antigens in genetic locus and therefore inheritance. These antigens are polymorphic glycoproteins comprising alpha and beta chains and are found on lymphoid and other cells, often associated with certain diseases.Membrane Glycoproteins: Glycoproteins found on the membrane or surface of cells.Cytotoxicity Tests, Immunologic: The demonstration of the cytotoxic effect on a target cell of a lymphocyte, a mediator released by a sensitized lymphocyte, an antibody, or complement.HLA-A1 Antigen: A specific HLA-A surface antigen subtype. Members of this subtype contain alpha chains that are encoded by the HLA-A*01 allele family.Cells, Cultured: Cells propagated in vitro in special media conducive to their growth. Cultured cells are used to study developmental, morphologic, metabolic, physiologic, and genetic processes, among others.Antigens: Substances that are recognized by the immune system and induce an immune reaction.Flow Cytometry: Technique using an instrument system for making, processing, and displaying one or more measurements on individual cells obtained from a cell suspension. Cells are usually stained with one or more fluorescent dyes specific to cell components of interest, e.g., DNA, and fluorescence of each cell is measured as it rapidly transverses the excitation beam (laser or mercury arc lamp). Fluorescence provides a quantitative measure of various biochemical and biophysical properties of the cell, as well as a basis for cell sorting. Other measurable optical parameters include light absorption and light scattering, the latter being applicable to the measurement of cell size, shape, density, granularity, and stain uptake.Peptide Mapping: Analysis of PEPTIDES that are generated from the digestion or fragmentation of a protein or mixture of PROTEINS, by ELECTROPHORESIS; CHROMATOGRAPHY; or MASS SPECTROMETRY. The resulting peptide fingerprints are analyzed for a variety of purposes including the identification of the proteins in a sample, GENETIC POLYMORPHISMS, patterns of gene expression, and patterns diagnostic for diseases.Glycosylation: The chemical or biochemical addition of carbohydrate or glycosyl groups to other chemicals, especially peptides or proteins. Glycosyl transferases are used in this biochemical reaction.Electrophoresis, Polyacrylamide Gel: Electrophoresis in which a polyacrylamide gel is used as the diffusion medium.Gene Products, env: Retroviral proteins, often glycosylated, coded by the envelope (env) gene. They are usually synthesized as protein precursors (POLYPROTEINS) and later cleaved into the final viral envelope glycoproteins by a viral protease.gp100 Melanoma Antigen: A melanosome-associated protein that plays a role in the maturation of the MELANOSOME.HLA-DRB1 Chains: A subtype of HLA-DRB beta chains that includes over one hundred allele variants. The HLA-DRB1 subtype is associated with several of the HLA-DR SEROLOGICAL SUBTYPES.Antigen-Presenting Cells: A heterogeneous group of immunocompetent cells that mediate the cellular immune response by processing and presenting antigens to the T-cells. Traditional antigen-presenting cells include MACROPHAGES; DENDRITIC CELLS; LANGERHANS CELLS; and B-LYMPHOCYTES. FOLLICULAR DENDRITIC CELLS are not traditional antigen-presenting cells, but because they hold antigen on their cell surface in the form of IMMUNE COMPLEXES for B-cell recognition they are considered so by some authors.Vaccines: Suspensions of killed or attenuated microorganisms (bacteria, viruses, fungi, protozoa), antigenic proteins, synthetic constructs, or other bio-molecular derivatives, administered for the prevention, amelioration, or treatment of infectious and other diseases.Carbohydrate Sequence: The sequence of carbohydrates within POLYSACCHARIDES; GLYCOPROTEINS; and GLYCOLIPIDS.Viral Core Proteins: Proteins found mainly in icosahedral DNA and RNA viruses. They consist of proteins directly associated with the nucleic acid inside the NUCLEOCAPSID.Fluorescent Antibody Technique: Test for tissue antigen using either a direct method, by conjugation of antibody with fluorescent dye (FLUORESCENT ANTIBODY TECHNIQUE, DIRECT) or an indirect method, by formation of antigen-antibody complex which is then labeled with fluorescein-conjugated anti-immunoglobulin antibody (FLUORESCENT ANTIBODY TECHNIQUE, INDIRECT). The tissue is then examined by fluorescence microscopy.Major Histocompatibility Complex: The genetic region which contains the loci of genes which determine the structure of the serologically defined (SD) and lymphocyte-defined (LD) TRANSPLANTATION ANTIGENS, genes which control the structure of the IMMUNE RESPONSE-ASSOCIATED ANTIGENS, HUMAN; the IMMUNE RESPONSE GENES which control the ability of an animal to respond immunologically to antigenic stimuli, and genes which determine the structure and/or level of the first four components of complement.PolysaccharidesCell Line, Transformed: Eukaryotic cell line obtained in a quiescent or stationary phase which undergoes conversion to a state of unregulated growth in culture, resembling an in vitro tumor. It occurs spontaneously or through interaction with viruses, oncogenes, radiation, or drugs/chemicals.Histocompatibility Antigen H-2D: A component of the murine major histocompatibility complex class I family. It contains one Ig-like C1-type domain and functions in processing and presentation of exogenous peptide antigens to the immune system.Immunoassay: A technique using antibodies for identifying or quantifying a substance. Usually the substance being studied serves as antigen both in antibody production and in measurement of antibody by the test substance.gag Gene Products, Human Immunodeficiency Virus: Proteins encoded by the GAG GENE of the HUMAN IMMUNODEFICIENCY VIRUS.Genes, MHC Class I: Genetic loci in the vertebrate major histocompatibility complex which encode polymorphic characteristics not related to immune responsiveness or complement activity, e.g., B loci (chicken), DLA (dog), GPLA (guinea pig), H-2 (mouse), RT-1 (rat), HLA-A, -B, and -C class I genes of man.HLA-DR4 Antigen: An HLA-DR antigen which is associated with HLA-DRB1 CHAINS encoded by DRB1*04 alleles.T-Cell Antigen Receptor Specificity: The property of the T-CELL RECEPTOR which enables it to react with some antigens and not others. The specificity is derived from the structure of the receptor's variable region which has the ability to recognize certain antigens in conjunction with the MAJOR HISTOCOMPATIBILITY COMPLEX molecule.Immunoglobulin Fab Fragments: Univalent antigen-binding fragments composed of one entire IMMUNOGLOBULIN LIGHT CHAIN and the amino terminal end of one of the IMMUNOGLOBULIN HEAVY CHAINS from the hinge region, linked to each other by disulfide bonds. Fab contains the IMMUNOGLOBULIN VARIABLE REGIONS, which are part of the antigen-binding site, and the first IMMUNOGLOBULIN CONSTANT REGIONS. This fragment can be obtained by digestion of immunoglobulins with the proteolytic enzyme PAPAIN.Bacterial Vaccines: Suspensions of attenuated or killed bacteria administered for the prevention or treatment of infectious bacterial disease.Antigens, CD4: 55-kDa antigens found on HELPER-INDUCER T-LYMPHOCYTES and on a variety of other immune cell types. CD4 antigens are members of the immunoglobulin supergene family and are implicated as associative recognition elements in MAJOR HISTOCOMPATIBILITY COMPLEX class II-restricted immune responses. On T-lymphocytes they define the helper/inducer subset. CD4 antigens also serve as INTERLEUKIN-15 receptors and bind to the HIV receptors, binding directly to the HIV ENVELOPE PROTEIN GP120.HIV Infections: Includes the spectrum of human immunodeficiency virus infections that range from asymptomatic seropositivity, thru AIDS-related complex (ARC), to acquired immunodeficiency syndrome (AIDS).Mutation: 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.Cloning, Molecular: 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.Immunoglobulin E: An immunoglobulin associated with MAST CELLS. Overexpression has been associated with allergic hypersensitivity (HYPERSENSITIVITY, IMMEDIATE).Molecular Weight: The sum of the weight of all the atoms in a molecule.Leukocytes, Mononuclear: Mature LYMPHOCYTES and MONOCYTES transported by the blood to the body's extravascular space. They are morphologically distinguishable from mature granulocytic leukocytes by their large, non-lobed nuclei and lack of coarse, heavily stained cytoplasmic granules.Cattle: 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.Viral Matrix Proteins: Proteins associated with the inner surface of the lipid bilayer of the viral envelope. These proteins have been implicated in control of viral transcription and may possibly serve as the "glue" that binds the nucleocapsid to the appropriate membrane site during viral budding from the host cell.Alleles: Variant forms of the same gene, occupying the same locus on homologous CHROMOSOMES, and governing the variants in production of the same gene product.Amino Acid Substitution: The naturally occurring or experimentally induced replacement of one or more AMINO ACIDS in a protein with another. If a functionally equivalent amino acid is substituted, the protein may retain wild-type activity. Substitution may also diminish, enhance, or eliminate protein function. Experimentally induced substitution is often used to study enzyme activities and binding site properties.Dendritic Cells: Specialized cells of the hematopoietic system that have branch-like extensions. They are found throughout the lymphatic system, and in non-lymphoid tissues such as SKIN and the epithelia of the intestinal, respiratory, and reproductive tracts. They trap and process ANTIGENS, and present them to T-CELLS, thereby stimulating CELL-MEDIATED IMMUNITY. They are different from the non-hematopoietic FOLLICULAR DENDRITIC CELLS, which have a similar morphology and immune system function, but with respect to humoral immunity (ANTIBODY PRODUCTION).HLA-DRB4 Chains: A subtype of HLA-DRB beta chains that is associated with the HLA-DR53 serological subtype.Plasmodium falciparum: A species of protozoa that is the causal agent of falciparum malaria (MALARIA, FALCIPARUM). It is most prevalent in the tropics and subtropics.Nucleoproteins: Proteins conjugated with nucleic acids.Computational Biology: A field of biology concerned with the development of techniques for the collection and manipulation of biological data, and the use of such data to make biological discoveries or predictions. This field encompasses all computational methods and theories for solving biological problems including manipulation of models and datasets.Immunity, Cellular: Manifestations of the immune response which are mediated by antigen-sensitized T-lymphocytes via lymphokines or direct cytotoxicity. This takes place in the absence of circulating antibody or where antibody plays a subordinate role.Tumor Cells, Cultured: Cells grown in vitro from neoplastic tissue. If they can be established as a TUMOR CELL LINE, they can be propagated in cell culture indefinitely.HLA-D Antigens: Human immune-response or Class II antigens found mainly, but not exclusively, on B-lymphocytes and produced from genes of the HLA-D locus. They are extremely polymorphic families of glycopeptides, each consisting of two chains, alpha and beta. This group of antigens includes the -DR, -DQ and -DP designations, of which HLA-DR is most studied; some of these glycoproteins are associated with certain diseases, possibly of immune etiology.Immunologic Memory: The altered state of immunologic responsiveness resulting from initial contact with antigen, which enables the individual to produce antibodies more rapidly and in greater quantity in response to secondary antigenic stimulus.Structure-Activity Relationship: The relationship between the chemical structure of a compound and its biological or pharmacological activity. Compounds are often classed together because they have structural characteristics in common including shape, size, stereochemical arrangement, and distribution of functional groups.Macaca mulatta: A species of the genus MACACA inhabiting India, China, and other parts of Asia. The species is used extensively in biomedical research and adapts very well to living with humans.Genetic Vectors: DNA molecules capable of autonomous replication within a host cell and into which other DNA sequences can be inserted and thus amplified. Many are derived from PLASMIDS; BACTERIOPHAGES; or VIRUSES. They are used for transporting foreign genes into recipient cells. Genetic vectors possess a functional replicator site and contain GENETIC MARKERS to facilitate their selective recognition.Trisaccharides: Oligosaccharides containing three monosaccharide units linked by glycosidic bonds.Immunization, Passive: Transfer of immunity from immunized to non-immune host by administration of serum antibodies, or transplantation of lymphocytes (ADOPTIVE TRANSFER).Immunotherapy: Manipulation of the host's immune system in treatment of disease. It includes both active and passive immunization as well as immunosuppressive therapy to prevent graft rejection.Microscopy, Immunoelectron: Microscopy in which the samples are first stained immunocytochemically and then examined using an electron microscope. Immunoelectron microscopy is used extensively in diagnostic virology as part of very sensitive immunoassays.Mice, Inbred Strains: Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations, or by parent x offspring matings carried out with certain restrictions. All animals within an inbred strain trace back to a common ancestor in the twentieth generation.Immunosorbent Techniques: Techniques for removal by adsorption and subsequent elution of a specific antibody or antigen using an immunosorbent containing the homologous antigen or antibody.Hemagglutinin Glycoproteins, Influenza Virus: Membrane glycoproteins from influenza viruses which are involved in hemagglutination, virus attachment, and envelope fusion. Fourteen distinct subtypes of HA glycoproteins and nine of NA glycoproteins have been identified from INFLUENZA A VIRUS; no subtypes have been identified for Influenza B or Influenza C viruses.Mucins: High molecular weight mucoproteins that protect the surface of EPITHELIAL CELLS by providing a barrier to particulate matter and microorganisms. Membrane-anchored mucins may have additional roles concerned with protein interactions at the cell surface.Glycoconjugates: Carbohydrates covalently linked to a nonsugar moiety (lipids or proteins). The major glycoconjugates are glycoproteins, glycopeptides, peptidoglycans, glycolipids, and lipopolysaccharides. (From Biochemical Nomenclature and Related Documents, 2d ed; From Principles of Biochemistry, 2d ed)HLA-DR7 Antigen: A HLA-DR antigen that is associated with HLA-DRB1 CHAINS encoded by DRB1*07 alleles.Genetic Variation: Genotypic differences observed among individuals in a population.Oligosaccharides: Carbohydrates consisting of between two (DISACCHARIDES) and ten MONOSACCHARIDES connected by either an alpha- or beta-glycosidic link. They are found throughout nature in both the free and bound form.Simian immunodeficiency virus: Species of the genus LENTIVIRUS, subgenus primate immunodeficiency viruses (IMMUNODEFICIENCY VIRUSES, PRIMATE), that induces acquired immunodeficiency syndrome in monkeys and apes (SAIDS). The genetic organization of SIV is virtually identical to HIV.Oncogene Proteins, Viral: Products of viral oncogenes, most commonly retroviral oncogenes. They usually have transforming and often protein kinase activities.Influenza A virus: 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.Serotyping: Process of determining and distinguishing species of bacteria or viruses based on antigens they share.Receptor-Like Protein Tyrosine Phosphatases, Class 8: A subclass of receptor-like protein tryosine phosphatases that contain an extracellular RDGS-adhesion recognition motif and a single cytosolic protein tyrosine phosphate domain.HLA-DR1 Antigen: An HLA-DR antigen associated with HLA-DRB1 CHAINS that are encoded by DRB1*01 alleles.HLA-DP beta-Chains: Transmembrane proteins that form the beta subunits of the HLA-DP antigens.Autoimmune Diseases: Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides.Viral Structural Proteins: Viral proteins that are components of the mature assembled VIRUS PARTICLES. They may include nucleocapsid core proteins (gag proteins), enzymes packaged within the virus particle (pol proteins), and membrane components (env proteins). These do not include the proteins encoded in the VIRAL GENOME that are produced in infected cells but which are not packaged in the mature virus particle,i.e. the so called non-structural proteins (VIRAL NONSTRUCTURAL PROTEINS).Radioimmunoassay: Classic quantitative assay for detection of antigen-antibody reactions using a radioactively labeled substance (radioligand) either directly or indirectly to measure the binding of the unlabeled substance to a specific antibody or other receptor system. Non-immunogenic substances (e.g., haptens) can be measured if coupled to larger carrier proteins (e.g., bovine gamma-globulin or human serum albumin) capable of inducing antibody formation.Melanoma: A malignant neoplasm derived from cells that are capable of forming melanin, which may occur in the skin of any part of the body, in the eye, or, rarely, in the mucous membranes of the genitalia, anus, oral cavity, or other sites. It occurs mostly in adults and may originate de novo or from a pigmented nevus or malignant lentigo. Melanomas frequently metastasize widely, and the regional lymph nodes, liver, lungs, and brain are likely to be involved. The incidence of malignant skin melanomas is rising rapidly in all parts of the world. (Stedman, 25th ed; from Rook et al., Textbook of Dermatology, 4th ed, p2445)Antigens, CD15: A trisaccharide antigen expressed on glycolipids and many cell-surface glycoproteins. In the blood the antigen is found on the surface of NEUTROPHILS; EOSINOPHILS; and MONOCYTES. In addition, CD15 antigen is a stage-specific embryonic antigen.Glutamate Decarboxylase: A pyridoxal-phosphate protein that catalyzes the alpha-decarboxylation of L-glutamic acid to form gamma-aminobutyric acid and carbon dioxide. The enzyme is found in bacteria and in invertebrate and vertebrate nervous systems. It is the rate-limiting enzyme in determining GAMMA-AMINOBUTYRIC ACID levels in normal nervous tissues. The brain enzyme also acts on L-cysteate, L-cysteine sulfinate, and L-aspartate. EC Antigens: A group of the D-related HLA antigens (human) found to differ from the DR antigens in genetic locus and therefore inheritance. These antigens are polymorphic glycoproteins comprising alpha and beta chains and are found on lymphoid and other cells, often associated with certain diseases.

Functional activities and epitope specificity of human and murine antibodies against the class 4 outer membrane protein (Rmp) of Neisseria meningitidis. (1/16637)

Antibodies against the class 4 outer membrane protein (OMP) from Neisseria meningitidis have been purified from sera from vaccinees immunized with the Norwegian meningococcal group B outer membrane vesicle vaccine. The human sera and purified antibodies reacted strongly with the class 4 OMP in immunoblots, whereas experiments with whole bacteria showed only weak reactions, indicating that the antibodies mainly reacted with parts of the class 4 molecule that were not exposed. The purified human anti-class 4 OMP antibodies and the monoclonal antibodies (MAbs) were neither bactericidal nor opsonic against live meningococci. Three new MAbs against the class 4 OMP were generated and compared with other, previously described MAbs. Three linear epitopes in different regions of the class 4 OMP were identified by the reaction of MAbs with synthetic peptides. The MAbs showed no blocking effect on bactericidal activity of MAbs against other OMPs. However, one of the eight purified human anti-class 4 OMP antibody preparations, selected from immunoblot reactions among sera from 27 vaccinees, inhibited at high concentrations the bactericidal effect of a MAb against the class 1 OMP. However, these antibodies were not vaccine induced, as they were present also before vaccination. Therefore, this study gave no evidence that vaccination with a meningococcal outer membrane vesicle vaccine containing the class 4 OMP induces blocking antibodies. Our data indicated that the structure of class 4 OMP does not correspond to standard beta-barrel structures of integral OMPs and that no substantial portion of the OmpA-like C-terminal region of this protein is located at the surface of the outer membrane.  (+info)

Salivary mucin MG1 is comprised almost entirely of different glycosylated forms of the MUC5B gene product. (2/16637)

The MG1 population of mucins was isolated from human whole salivas by gel chromatography followed by isopycnic density gradient centrifugation. The reduced and alkylated MG1 mucins, separated by anion exchange chromatography, were of similar size (radius of gyration 55-64 nm) and molecular weight (2.5-2.9 x 10(6) Da). Two differently-charged populations of MG1 subunits were observed which showed different reactivity with monoclonal antibodies to glycan epitopes. Monosaccharide and amino acid compositional analyses indicated that the MG1 subunits had similar glycan structures on the same polypeptide. An antiserum recognizing the MUC5B mucin was reactive across the entire distribution, whereas antisera raised against the MUC2 and MUC5AC mucins showed no reactivity. Western blots of agarose gel electrophoresis of fractions across the anion exchange distribution indicated that the polypeptide underlying the mucins was the product of the MUC5B gene. Amino acid analysis and peptide mapping performed on the fragments produced by trypsin digestion of the two MG1 populations yielded data similar to that obtained for MUC5B mucin subunits prepared from respiratory mucus (Thornton et al., 1997) and confirmed that the MUC5B gene product was the predominant mucin polypeptide present. Isolation of the MG1 mucins from the secretions of the individual salivary glands (palatal, sublingual, and submandibular) indicate that the palatal gland is the source of the highly charged population of the MUC5B mucin.  (+info)

Expression of trophinin, tastin, and bystin by trophoblast and endometrial cells in human placenta. (3/16637)

Trophinin, tastin, and bystin comprise a complex mediating a unique homophilic cell adhesion between trophoblast and endometrial epithelial cells at their respective apical cell surfaces. In this study, we prepared mouse monoclonal antibodies specific to each of these molecules. The expression of these molecules in the human placenta was examined immunohistochemically using the antibodies. In placenta from the 6th week of pregnancy, trophinin and bystin were found in the cytoplasm of the syncytiotrophoblast in the chorionic villi, and in endometrial decidual cells at the utero placental interface. Tastin was exclusively present on the apical side of the syncytiotrophoblast. Tissue sections were also examined by in situ hybridization using RNA probes specific to each of these molecules. This analysis showed that trophoblast and endometrial epithelial cells at the utero placental interface express trophinin, tastin, and bystin. In wk 10 placenta, trophinin and bystin were found in the intravillous cytotrophoblast, while tastin was not found in the villi. After wk 10, levels of all three proteins decreased and then disappeared from placental villi.  (+info)

Protection against lymphocytic choriomeningitis virus infection induced by a reduced peptide bond analogue of the H-2Db-restricted CD8(+) T cell epitope GP33. (4/16637)

Recent investigations have suggested that pseudopeptides containing modified peptide bonds might advantageously replace natural peptides in therapeutic strategies. We have generated eight reduced peptide bond Psi(CH2-NH) analogues corresponding to the H-2Db-restricted CD8(+) T cell epitope (called GP33) of the glycoprotein of the lymphocytic choriomeningitis virus. One of these pseudopeptides, containing a reduced peptide bond between residues 6 and 7 (Psi(6-7)), displayed very similar properties of binding to major histocompatibility complex (MHC) and recognition by T cell receptor transgenic T cells specific for GP33 when compared with the parent peptide. We assessed in vitro and in vivo the proteolytic resistance of GP33 and Psi(6-7) and analyzed its contribution to the priming properties of these peptides. The Psi(6-7) analogue exhibited a dramatically increased proteolytic resistance when compared with GP33, and we show for the first time that MHC-peptide complexes formed in vivo with a pseudopeptide display a sustained half-life compared with the complexes formed with the natural peptide. Furthermore, in contrast to immunizations with GP33, three injections of Psi(6-7) in saline induced significant antiviral protection in mice. The enhanced ability of Psi(6-7) to induce antiviral protection may result from the higher stability of the analogue and/or of the MHC-analogue complexes.  (+info)

Use of RhD fusion protein expressed on K562 cell surface in the study of molecular basis for D antigenic epitopes. (5/16637)

The human D antigens, one of the most clinically important blood groups, are presented by RhD protein with a putative 12 transmembrane topology. To understand the molecular basis for the complex antigenic profile of RhD protein, we expressed a series of RhD fusion proteins using different portions of Duffy protein as a tag in erythroleukemic K562 cells. Because the reactivity of monoclonal anti-RhD antibody, LOR15C9, depends mainly on the sequence coded by exon 7 of RhD, we altered DNA sequence corresponding to the amino acid residues 323-331(A) and 350-354(B) in the exon 7. The mutation in region B resulted in a severe reduction in LOR15C9 binding by flow cytometry analysis, suggesting that region B may play an important role in constituting antigen epitopes recognized by LOR15C9. On the other hand, a slight decrease in the antibody binding was observed for the region A mutant, suggesting that the intracellularly located region A may elicit a long distance effect on the formation of exofacial antigen epitopes. In addition, using various monoclonal antibodies against RhD, we compared the antigenic profile of expressed RhD fusion protein with that of endogenous RhD in K562 cells as well as in erythrocytes.  (+info)

Goodpasture antigen: expression of the full-length alpha3(IV) chain of collagen IV and localization of epitopes exclusively to the noncollagenous domain. (6/16637)

BACKGROUND: Tissue injury in Goodpasture (GP) syndrome (rapidly progressive glomerular nephritis and pulmonary hemorrhage) is mediated by antibasement membrane antibodies that are targeted to the alpha3(IV) chain of type IV collagen, one of five alpha(IV) chains that occur in the glomerular basement membrane. GP antibodies are known to bind epitopes within the carboxyl terminal noncollagenous domain (NC1) of the alpha3(IV) chain, termed the GP autoantigen. Whether epitopes also exist in the 1400-residue collagenous domain is unknown because studies to date have focused solely on the NC1 domain. A knowledge of GP epitopes is important for the understanding of the etiology and pathogenesis of the disease and for the development of therapeutic strategies. METHODS: A cDNA construct was prepared for the full-length human alpha3(IV) chain. The construct was stably transfected into human embryonic kidney 293 cells. The purified full-length r-alpha3(IV) chain was characterized by electrophoresis and electron microscopy. The capacity of this chain for binding of GP antibodies from five patients was compared with that of the human r-alpha3(IV)NC1 domain by competitive enzyme-linked immunosorbent assay. RESULTS: The r-alpha3(IV) chain was secreted from 293 cells as a single polypeptide chain that did not spontaneously undergo assembly into a triple-helical molecule. An analysis of GP-antibody binding to the full-length r-alpha3(IV) chain showed binding exclusively to the globular NC1 domain. CONCLUSION: The full-length human alpha3(IV) chain possesses the capacity to bind GP autoantibodies. The epitope(s) is found exclusively on the nontriple-helical NC1 domain of the alpha3(IV) chain, indicating the presence of specific immunogenic properties. The alpha3(IV) chain alone does not spontaneously undergo assembly into a triple-helical homotrimeric molecule, suggesting that coassembly with either the alpha4(IV) and/or the alpha5(IV) chain may be required for triple-helix formation.  (+info)

Identification of the human melanoma-associated chondroitin sulfate proteoglycan antigen epitope recognized by the antitumor monoclonal antibody 763.74 from a peptide phage library. (7/16637)

To identify the epitope of the melanoma-associated chondroitin sulfate proteoglycan (MCSP) recognized by the monoclonal antibody (mAb) 763.74, we first expressed random DNA fragments obtained from the complete coding sequence of the MCSP core glycoproteins in phages and selected without success for binders to the murine mAb 763.74. We then used a library of random heptapeptides displayed at the surface of the filamentous M13 phage as fusion protein to the NH2-terminal portion of the minor coat protein III. After three rounds of selection on the bound mAb, several phages displaying related binding peptides were identified, yielding the consensus sequence Val-His-Leu-Asn-Tyr-Glu-His. Competitive ELISA experiments showed that this peptide can be specifically prevented from binding to mAb 763.74 by an anti-idiotypic MK2-23 mouse:human chimeric mAb and by A375 melanoma cells expressing the antigen MCSP. We screened the amino acid sequence of the MCSP molecule for a region of homology to the consensus sequence and found that the amino acid sequence Val-His-Ile-Asn-Ala-His spanning positions 289 and 294 has high homology. Synthetic linear peptides corresponding to the consensus sequence as well as to the MCSP-derived epitope inhibit the binding of mAb 763.74 to the phages displaying the consensus amino acid sequence. Finally, the biotinylated consensus peptide absorbed to streptavidin-microtiter plates can be used for the detection of mAb 763.74 in human serum. These results show clearly that the MCSP epitope defined by mAb 763.74 has been identified.  (+info)

Induction of lasting complete regression of preformed distinct solid tumors by targeting the tumor vasculature using two new anti-endoglin monoclonal antibodies. (8/16637)

Endoglin (EDG, CD105) is a proliferation-associated antigen on endothelial cells. In this study, two new anti-EDG monoclonal antibodies (mAbs) Y4-2F1 (or termed SN6j) and P3-2G8 (SN6k) were generated and used for treating distinct preformed tumors. These mAbs, both IgG1-kappa antibodies, cross-reacted weakly with mouse endothelial cells but defined epitopes different from the epitope defined by a previously reported anti-EDG mAb K4-2C10 (B. K. Seon et al., Clin. Cancer Res., 3: 1031-1044, 1997). SN6j and SN6k reacted strongly with human endothelial cells and vascular endothelium of malignant human tissues but showed no significant reactivity with tumor cells per se. The deglycosylated ricin A chain (dgRA) conjugates of the two mAbs showed a weak but specific cytotoxic activity against murine endothelial cells in vitro. In the therapeutic studies, severe combined immunodeficient mice were inoculated s.c. with MCF-7 human breast cancer cells and left untreated until palpable tumors of distinct size (4-6 mm in diameter) appeared. Mice with the distinct tumors were treated by i.v. administration of individual anti-EDG conjugates, unconjugated mAbs, or a control conjugate. Long-lasting complete regression of the tumors was induced in the majority of tumor-bearing mice (n = 8 for each conjugate) when 40 microg of the individual conjugates were administered three times via the tail vein. It is remarkable that the tumors remained regressed without further therapy for as long as the mice were followed (i.e., 100 days). Control conjugate did not induce regression of the tumors in any of the treated mice, although weak nonspecific effects were observed in some of the mice (n = 8). The effects of unconjugated mAbs were small with the dose used, i.e., 34 microg three times. The anti-EDG conjugates showed antiangiogenic activity in the dorsal air sac assay in mice. The results suggest good potential of these conjugates for the clinical application.  (+info)

  • By integrating peptide features associated with presentation and recognition, we developed a model of tumor epitope immunogenicity that filtered out 98% of non-immunogenic peptides with a precision above 0.70. (psjhealth.org)
  • Key Parameters of Tumor Epitope Immunogenicity Revealed Through a Cons" by Daniel K Wells, Marit M van Buuren et al. (psjhealth.org)
  • Many approaches to identify therapeutically relevant neoantigens couple tumor sequencing with bioinformatic algorithms and inferred rules of tumor epitope immunogenicity. (psjhealth.org)
  • However, there are no reference data to compare these approaches, and the parameters governing tumor epitope immunogenicity remain unclear. (psjhealth.org)
  • These findings were validated in an independent cohort of 310 epitopes prioritized from tumor sequencing data and assessed for T cell binding. (psjhealth.org)
  • Predicting the binding of T cell receptors (TCRs) to epitopes plays a vital role in the immunotherapy, because it guides the development of therapeutic vaccines and cancer treatments. (aminer.cn)
  • DI-fusion Epitopes recognized by human T lymphocytes in the ROP2. (ac.be)
  • These findings indicate that the HIV-1 genome might encode and deploy a large potential repertoire of unconventional epitopes to enhance vaccine-induced antiviral immunity. (harvard.edu)
  • Identification and Characterization of Haemagglutinin Epitopes of Avibacterium Paragallinarum Serovar C." Veterinary Microbiology, vol. 131, no. 3-4, 2008, pp. 406-13. (unboundmedicine.com)
  • This dominant WNV peptide epitope, termed SVG9, lies within a highly conserved region of the envelope glycoprotein and demonstrates 100% homology among contemporary WNV strains. (jimmunol.org)
  • Association of idiotype-specific T cell responses with previously documented molecular remissions in idiotype-vaccinated patients suggests that the newly identified T cell epitopes may be clinically relevant. (jci.org)
  • A neoantigenic determinant is an epitope on a neoantigen, which is a newly formed antigen that has not been previously recognized by the immune system. (wikipedia.org)
  • 13 ) have the potential to generate novel epitopes that might serve as targets for an immune response. (aacrjournals.org)
  • The results indicate a general mechanism in which thiol-reactive haptens generate cryptic epitopes normally concealed from the immune system. (sigmaaldrich.com)
  • Since immune cross reactivity has been reported within the Dengue virus serogroup, we hypothesized that T cells specific for this A*0201 restricted WNV stretch of envelope would cross-recognize different flaviviruses due to epitope conservation. (jimmunol.org)
  • Conformational Occlusion of Blockade Antibody Epitopes, a Novel Mechanism of GII.4 Human Norovirus Immune Evasion. (bioportfolio.com)
  • The data describe a novel immune escape mechanism and better define suitable target epitopes for ATT. (rupress.org)
  • The objectives of this study were to identify haemagglutinin (HA) epitopes of Avibacterium paragallinarum serovar C that are capable of eliciting haemagglutination inhibition (HI) antibody, and to investigate their immunogenic role. (unboundmedicine.com)
  • VirScan highlights both donor and recipient contributions to the viral antibody repertoire, and acquisition of new viral epitopes after HCT. (bloodjournal.org)
  • Age, CMV serostatus, and receipt of glucocorticoids correlate with recognition of viral epitopes after HCT. (bloodjournal.org)
  • There are several servers that attempt to predict epitopes . (proteopedia.org)
  • However, as far as we are aware, no systematic work has yet been conducted using the 3D structure of a virus to identify novel epitopes. (psu.edu)
  • How can cryptic epitopes trigger autoimmunity? (wikipedia.org)
  • Caged fluorescent haptens reveal the generation of cryptic epitopes in allergic contact dermatitis. (sigmaaldrich.com)
  • CARLSBAD, Calif.-- Invitrogen , maker of research tools for gene cloning and expression, has been granted exclusive worldwide license to market a line of products incorporating Vyrex 's reading frame independent epitope tagging technology. (genomeweb.com)
  • However, self epitopes which appear in very low concentration on APC are termed cryptic in the sense that they do not delete autoreactive T-cells which will then join the peripheral adult T cell repertoire. (wikipedia.org)
  • B cell epitopes of gliadin. (nih.gov)
  • Examples include imaging of of O-GlcNAc, O-GalNAc (Tn antigen), T antigen, sialyllactosamine (sLN), hyaluronan (HA), and heparan sulfate epitopes in different cell lines. (rndsystems.com)
  • Rubinstein ND, Mayrose I, Pupko T. A machine-learning approach for predicting B-cell epitopes. (proteopedia.org)
  • Interaction Profiling of T-Cell Epitopes with MHC-Class I Molecul. (ingentaconnect.com)
  • While Ab's specific for tumor idiotype have been well described in patients with B cell malignancies, the precise antigenic epitopes in human idiotype recognized by autologous T cells remain largely unknown. (jci.org)
  • Epitopes recognized by the T-cell receptor are often located in the inner, unexposed side of the antigen, and become accessible to the T-cell receptors after proteolytic processing of the antigen. (citizendium.org)
  • Tissue, cells or virus corresponding to Zebrafish Gut Secretory Cell Epitopes. (abcam.com)
  • IHC image of Zebrafish Gut Secretory Cell Epitopes staining in a section of formalin-fixed paraffin-embedded Zebra fish Larvae (5 days) performed on a Leica BOND™ system using the standard protocol F. The section was pre-treated using heat mediated antigen retrieval with sodium citrate buffer (pH6, epitope retrieval solution 1) for 20mins. (abcam.com)
  • Human MHC class I epitopes derived from PAP have been identified previously, and peptide-specific CTLs have been shown to be able to lyse an MHC-restricted prostate cancer cell line. (aacrjournals.org)
  • In humans, few β-cell epitopes have been reported, thereby limiting the study of β-cell-specific CTLs in type 1 diabetes. (diabetesjournals.org)
  • These data suggest that many β-cell epitopes are recognized by CTLs in recent-onset type 1 diabetic patients. (diabetesjournals.org)
  • The first two, GAD114-123 ( 8 ) and insulin B chain 22-30 ( 9 ), were chosen for study based on homology to known NOD CD4 + T-cell epitopes and then confirmed by culturing and expanding CD8 + T-cells in vitro from the peripheral blood of HLA-A*0201 and HLA-A*2402 type 1 diabetic patients, respectively. (diabetesjournals.org)
  • The McMaster T-cell Epitope Centre (MTEC) uses new epitope-specific tools to determine the frequency and function of T cells reactive with the cat allergen, Fel d 1. (mcmaster.ca)
  • Epitopes recognized by the B-Cell receptor are located on the surface of the Antigen . (online-medical-dictionary.org)
  • It is important to note that a unique antibody is produced by a B cell lymphocyte which recognizes and binds to a single unique epitope. (prosci-inc.com)
  • Nine previously uncharacterized CD8+ T cell epitopes were identified from HSV-2 infected BALB/c mice. (mdpi.com)
  • A further amino acid substitution at position 70 resulted in the gain of additional H-2D d specificities, allowing to localize more than half of all the relevant H-2D d serological epitopes to position 63 to 70. (springer.com)
  • For this study, we will focus exclusively on using the Deadlock(tm) to create and test multiple derivatives of a 6 amino acid peptide that is known to be the epitope for 4E10. (sbir.gov)
  • Equally important, we show that the force-induced conformation exposes hidden epitopes previously buried in the Tfp fiber. (pnas.org)