Cross Reactive Idiotypic Determinants on (T,G)-A--L Specific Antibodies of High and Low Responder Mice

Mice possessing the H-2^b haplotype produce high antibody titers when immunized with (T,G)-A--L, whereas mice possessing the H-2^k haplotype are low responders to this immunogen. Following immunization with either (Phe,G)-A--L or (T,G)-A--L complexed with methylated bovine serum albumin (MBSA), low responder as well as high responder mice produce antibodies which can be titrated with (T,G)-A--L. The variable regions of antibodies produced against the above immunogens were compared utilizing guinea pig sera against (T,G)-A--L idiotypes of C3H.SW (H-2^b, Ig-1^a) mice, which appear to be allotype linked. (T,G)-A--L specific antibodies were isolated from sera of H-2^b (Ig-1^a) and H-2^k (Ig-1^a) mice immunized with (Phe,G)-A--L. These antibodies inhibited 50% of the ¹²⁵I-idiotype to the anti-idiotypes. In contrast, a population of antibodies isolated from the (Phe,G)-A--L specific antisera which bound only ¹²⁵I-modified (Phe,G)-A--L did not react with the anti idiotypes.