Monoclonal antibodies reveal three types of idiotypic determinants on MOPC 173: H-L-specific private and public idiotopes, and Vh-specific public idiotope(s).

Monoclonal anti-idiotypic antibodies against the IgG2a, K myeloma protein MOPC 173 were raised with A/J- and CBA-immune B-cells. The specificity of the antibodies was studied by hemagglutination and inhibition of a radioimmunoassay (RIA). A series of myeloma proteins, their H- and L-chains, free or reassociated in various combinations, were used as inhibitors. The RIA patterns allow recognition of three types of idiotypic determinants: private conformational idiotope(s), a public conformational idiotope, and public VH-determinant(s). Strain distribution of the public determinant was studied. A tentative correlation between amino acid positions and Id determinants is discussed.