Allotypy of rabbit immunoglobulins: a fifth allele at the a locus.

Studies in wild rabbits (Oryctolagus cuniculus) allowed the detection of a fifth allele (a101) at the a locus of rabbit immunoglobulins. The structures responsible for the A101 allotypic specificity have been found on both IgG and IgM. Their location is on the Fab fragment, on the H chain. None of the rabbits possessing A101 allotypic specificity possessed two known allotypic specificities of the a series. Genetic evidence by breeding studies agree with assignment of A101 to the a series and allow to designate this allotypic specificity as a101. a101 has been found in wild rabbits in different areas in France. It has no detectable cross-reactivity with the known allotypes. The genetic polymorphism of immunoglobulins is much larger in the Oryctolagus cuniculus species than the one described in the domestic form of the species.