Mapping the orientation of an antigenic peptide bound in the antigen binding groove of H-2Kb using a monoclonal antibody.
The major histocompatibility complex class I molecules are receptors for intracellular peptides, both of self and non-self origin. When non-self peptides (eg., pathogen derived) are bound to the class I molecules, they form ligands for T cell receptors resulting in antigen specific lysis of the infected cells by cytotoxic T lymphocytes. Therefore, an understanding of the process of antigen recognition requires the precise definition of the structural features of the bimolecular complex formed by a single well defined antigenic peptide bound to the class I molecule. A strategy using antibodies was developed to probe the structural features of the H-2Kb containing a defined peptide in the antigen cleft. We report that the binding surface area of a Kb specific monoclonal antibody (28-13-3s) includes residues in the alpha 1 (Gly56 and Glu58) and alpha 2 (Trp167) helices of Kb thus, binding across the antigen binding groove. When cells treated with the antigenic peptide of vesicular stomatitis virus, N52-59, and its alanine substituted analogs were tested for 28-13-3s binding, it was found that position 1 of the peptide also forms a part of the antibody binding site. This finding strongly supports the positioning of the N-terminus of N52-59 proximal to pocket A, thus, assuming an orientation parallel to the alpha 1 helix.
Joyce
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Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461.
Sun
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Nathenson
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D000011:Abelson murine leukemia virus / Q000235:genetics; D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes; D002460:Cell Line; D000939:Epitopes / Q000737:chemistry*; D005805:Genes, MHC Class I; D006183:H-2 Antigens / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D011487:Protein Conformation; D011925:Rauscher Virus / Q000235:genetics; D013601:T-Lymphocytes
D000911:Antibodies, Monoclonal; D000939:Epitopes; D006183:H-2 Antigens