title: HLA-B27 antigenicity: antibodies against the chemically synthesized 63-84 peptide from HLA-B27.1 display alloantigenic specificity and discriminate among HLA-B27 subtypes.
abstract: A chemically synthesized peptide with an amino acid sequence identical to that of the segment spanning residue 63-84 of the major HLA-B27.1 subtype antigen has been obtained. Specific antibodies were raised in rabbits against this peptide, coupled to keyhole limpet hemocyanin carrier. These antibodies lysed lymphoblastoid cell lines expressing HLA-B27.1 in a complement-mediated cytotoxicity assay. They lysed neither B27-negative target cells, nor B27-positive cells expressing other B27 subtype antigens. Complement-mediated lysis of B27.1-positive targets was inhibited by free peptide and by peptide coupled to an unrelated carrier. In addition, the lytic action of the rabbit antiserum was blocked by a monoclonal antibody with no complement-activating capacity that under the conditions of the assay, was specific for HLA-B27. These results indicate that rabbit antibodies against the 63-84 peptide recognize the native HLA-B27.1 antigen; this antiserum is allospecific in character; and it discriminates among B27 subtypes. Thus the data provide direct evidence on the contribution of the hypervariable region spanning residues 63-84 to the alloantigenic specificity of HLA-B27.
mesh_terms: D000918:Antibody Specificity; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D002851:Chromatography, High Pressure Liquid; D003165:Complement System Proteins; D003601:Cytotoxicity Tests, Immunologic; D000939:Epitopes / Q000276:immunology*; D006680:HLA Antigens / Q000276:immunology*; D015796:HLA-B27 Antigen; D007106:Immune Sera / Q000032:analysis; D007518:Isoantibodies / Q000032:analysis* / Q000502:physiology; D010446:Peptide Fragments / Q000276:immunology*; D013329:Structure-Activity Relationship
chemical_list: D000954:Antigens, Surface; D000939:Epitopes; D006680:HLA Antigens; D015796:HLA-B27 Antigen; D007106:Immune Sera; D007518:Isoantibodies; D010446:Peptide Fragments; D003165:Complement System Proteins