Antibody diversity in amphibians: evidence for the inheritance of idiotypic specificities in isogenic Xenopus.

Two families of isogenic Xenopus and the progeny from one individual of each family were immunized with dinitrophenylated keyhole limpet hemocyanin. Antisera were raised in mice and in guinea pigs against purified antibodies from one individual of the first generation of each family. These were rendered anti-idiotypic by absorption with immunoglobulins of unimmunized isogenic frogs. In the first generation, antibodies from individuals of each family exhibited a high degree of idiotypic cross-reactivity. Antibodies from individuals of the second generation displayed idiotypic cross-reactivity, but to a lesser extent. Some idiotypic cross-reactivity was seen between members of one family with members of the other family: no sharing of idiotypic specificity was detected among anti-DNP antibodies isolated from individual outbred frogs. Isoelectric focusing (IEF) patterns of the anti-DNP antisera showed a high degree of restriction and overlap within members of each family and across two generations. Furthermore, the N-terminal sequence of the L chains from X. laevis anti-DNP antibodies was unique, and there was a low degree of structural heterogeneity in the H chain N-terminal region. A correlation between the IEF banding pattern and idiotypic reactivity was apparent. The data suggest the inheritance of variable region genes through two generations of isogenic Xenopus.