Allotypes in Basilea rabbits.

Basilea rabbits produce immunoglobulin molecules, practically all of which have lambda light chains rather than kappa chains. This variant strain was derived form a homozygous (b9/b9) male. Sensitive serological methods revealed that at least some homozygous bas/bas individuals possess traces (about 100 ng/ml) of b9 molecules. This level usually increases to almost 1 microgram/ml upon hyperimmunization with pneumococcal or streptococcal vaccines. One exceptional rabbit, with 50 micrograms/ml of b9 molecules, was found. In spite of the presence of b9 molecules in early pre-immune bleeds, homozygous bas/bas rabbits produce strong anti-b9 antibodies; i.e., they are capable of making autoantibodies. These anti-b9 allotypic antisera were not distinguishable by our methods from routinely produced anti-b9.