title: Complete variable region sequences of five homologous high affinity anti-digoxin antibodies.
abstract: High affinity murine A/J anti-digoxin monoclonal antibodies exhibit diversity in binding specificity for structurally related cardiac glycosides. They utilize several VH and VL genes. Among this diverse set, however, five antibodies share V region amino-terminal sequences that are remarkably homologous. The five antibodies were divided into three subsets based on different fine specificity-binding patterns. Therefore, complete V region sequences were determined by Edman degradation and by nucleotide sequence analysis. The VH region homology among the five antibodies was 84 to 100% and the VL region homology was 89 to 99%. The sequence data are consistent with the use of single (or closely related) VH and VL genes encoding the five antibodies. Four antibodies, derived from the same fusion (40-40, 40-120, 40-140, and 40-160), use identical D, JH2, and JK5 gene segments and identical junctions suggesting that they are clonally related. The fifth antibody (35-20) uses different D and JH1 gene segments but the same JK5 gene segment. All five antibodies share a cross-reactive idiotype. The three antibodies that exhibit the greatest degree of homology (40-40, 40-120, and 40-140) also share indistinguishable antigen-binding patterns as well as private idiotopes not present on the other two antibodies. Antibody 40-160, which has the next most homologous sequence, shares idiotopes with the first set but binds preferentially to different sites on the hapten, whereas antibody 35-20 has the most divergent sequence. In general, the degree of sequence homology among the five antibodies correlates with their hierarchical order based on hapten and idiotype fine specificity patterns.
authors: Department of Medicine, Massachusetts General Hospital, Boston.
authors: D J
authors: DJ
authors: Panka
authors: M N
authors: MN
authors: Margolies
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics* / Q000276:immunology; D000915:Antibody Affinity; D000916:Antibody Diversity; D000918:Antibody Specificity; D001483:Base Sequence; D002301:Cardiac Glycosides / Q000276:immunology; D003429:Cross Reactions; D004077:Digoxin / Q000276:immunology*; D005803:Genes, Immunoglobulin; D007130:Immunoglobulin Idiotypes / Q000276:immunology; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D051379:Mice; D008805:Mice, Inbred A / Q000235:genetics / Q000276:immunology; D008969:Molecular Sequence Data; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000911:Antibodies, Monoclonal; D002301:Cardiac Glycosides; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D004077:Digoxin