title: Complete amino acid sequence of the heavy-chain variable region from an A/J mouse antigen-nonbinding monoclonal antibody bearing the predominant arsonate idiotype.
abstract: The 1F6 hybridoma protein, exhibiting the predominant cross-reactive idiotype (CRI) associated with the immune response to p-azophenylarsonate in A/J mice but failing to bind the hapten arsonate, was elicited following immunization with rat anti-CRI [Wysocki, L.J., & Sato, V. (1981) Eur. J. Immunol. 11, 832-839]. The dissociation of idiotype and antigen binding in this hybridoma provides an opportunity to determine structural features involved in antigen binding and idiotypic sites. The complete heavy-chain variable region (VH) amino acid sequence was obtained by automated Edman degradation of the intact chain and fragments due to CNBr cleavage, trypsin digestion, mild acid hydrolysis, and carboxypeptidase A digestion of a CNBr fragment. Comparison of the CRI+ arsonate-nonbinding 1F6 sequence with the CRI+ germ-line VH gene sequence reveals that the 1F6 heavy chain differs from the germ-line-encoded amino acid sequence at seven positions within VH [Siekevitz, M., Gefter, M. L., Brodeur, P., Riblet, R., & Marshak-Rothstein, A. (1982) Eur. J. Immunol. 12, 1023-1032]. The 1F6 VH appears to arise from the CRI+ germ-line VH by somatic mutation at at least seven amino acid residues, each of which could be due to a single nucleotide base change. The diversity (D) gene-encoded segment of 1F6 is similar to that of the CRI+ antigen-binding hybridoma 36-65 except for two amino acid substitutions. Further, the idiotype (CRI) is preserved despite use of a JH4 gene segment in 1F6 as compared to JH2 in all CRI+ arsonate-binding hybridomas examined to date.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal; D001391:Azo Compounds; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D003488:Cyanogen Bromide; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D051379:Mice; D008805:Mice, Inbred A; D010446:Peptide Fragments / Q000032:analysis; D014357:Trypsin; D010132:p-Azobenzenearsonate
chemical_list: D000911:Antibodies, Monoclonal; D001391:Azo Compounds; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D010446:Peptide Fragments; D010132:p-Azobenzenearsonate; D002268:Carboxypeptidases; D043422:Carboxypeptidases A; D014357:Trypsin; D003488:Cyanogen Bromide