Structural basis for M-173 idiotypic determinants distinctively recognized in syngeneic and allogeneic immunization: contribution of DH, JH, and J kappa regions to an idiotope recognized by allogeneic antisera.

Antiidiotypic antibodies directed against the M-173 (IgG2a) mouse myeloma protein have been raised in syngeneic and allogeneic conditions. The antiidiotypic repertoires of several strains of mice have been compared by isoelectrofocusing, and a major idiotype has been identified by several antisera raised in allogeneic conditions in strains of mice which did not express the Igh-Ca allotype of the BALB background. Since this idiotype could be reformed in hybrid molecules containing the M-173 heavy chains and light chains which contained the J kappa 2 region, we propose that this determinant is dependent upon the J kappa 2, DH and JH regions, in addition, most probably, to a specific contribution of residues 45 and 54 of the heavy chains.