The inheritance of antibody V regions in the rabbit: linkage of an H- chain-specific idiotype to immunoglobulin allotypes

Anti-idiotype antibodies specific for the H chain of an homogeneous antistreptococcal antibody (4135 Ab) were prepared by injection of recombinant molecules consisting of the H chains from 4135 Ab and L chains isolated from the injected rabbit. The antibodies prepared in this fashion (anti-HId) were specific for the VH region of 4135 Ab. Using this preparation in an inhibition of binding assay, sera from rabbits related and unrelated to 4135 were screened for the presence of the 4135 HId. It was found that about 45% of the related rabbits, when immunized with streptococcal Group C vaccine, produced antibodies with a cross-reactive idiotype, while less than 10% of similarly immunized unrelated rabbits produced molecules bearing HId. The expression of HId was linked to the a3 allotype present in the H chain allogroup J. Antibody molecules bearing the HId determinant were isolated from heterozygous (a1a3 and a2a3) rabbits and shown to express the a3 allotype. One rabbit lacking the a3 allotype produced significant amounts of antibodies expressing HId. These antibodies were found to express both VH and CH allo-types characteristic of the J allogroup, although neither allotype was found in a preimmune IgG sample from this rabbit.