Anti-idiotypic antibodies of a predefined specificity generated against CDR3VH synthetic peptides define a private anti-CD4 idiotype.
A synthetic peptide corresponding to the third complementarity determining region (CDR) of the heavy chain (CDR3VH) of anti-Leu3a, a monoclonal anti-CD4 antibody which inhibits HIV gp120 binding to CD4, was used to elicit specific anti-peptide antibodies in rabbits. The anti-peptide antisera showed anti-idiotypic antibody (anti-Id) activity and recognized both the immunizing peptide and the intact cognate protein by ELISA. In addition, the antisera reacted with isolated heavy chains of anti-Leu3a by Western blot analysis. The lack of reactivity with a panel of monoclonal anti-CD4 antibodies suggested that the anti-peptide antisera recognize a private idiotype (Id) associated with the anti-Leu3a CDR3VH region. Further studies demonstrated the inability of the rabbit antisera to inhibit the binding of anti-Leu3a to the CD4 molecule. In addition, soluble recombinant CD4 was unable to inhibit the binding of the rabbit anti-peptide antisera to anti-Leu3a indicating that the CDR3VH region may not be involved in CD4 recognition. Anti-Id containing sera from mice, rabbits and nonhuman primates immunized with the intact anti-Leu3a molecule did not bind the CDR3VH synthetic peptide, suggesting that the corresponding region of anti-Leu3a may not represent an immunodominant idiotypic determinant in thes e species. These results suggest the potential use of synthetic peptides corresponding to immunoglobulin variable (V) region amino acid sequences in generating anti-Id reagents of a predefined specificity. In addition, V-region synthetic peptides may be useful in mapping the idiotopes recognized by an anti-Id response to the cognate molecule.
Attanasio
R
R
Department of Virology and Immunology, Southwest Foundation for Biomedical Research, San Antonio, TX 78284.
Kennedy
R C
RC
Allan
J S
JS
Maino
V C
VC
Buck
D
D
Kanda
P
P
D000595:Amino Acid Sequence; D000818:Animals; D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D015153:Blotting, Western; D015704:CD4 Antigens / Q000276:immunology*; D007143:Immunoglobulin Heavy Chains / Q000276:immunology; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region / Q000276:immunology; D008969:Molecular Sequence Data; D010455:Peptides / Q000276:immunology; D011817:Rabbits
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D007143:Immunoglobulin Heavy Chains; D007130:Immunoglobulin Idiotypes; D007135:Immunoglobulin Variable Region; D010455:Peptides