Identical sequence of light chains from rabbit anti-streptococcal antibodies.

Abstract

CONSIDERABLE advances have been made with special breeding programmes in the selection of rabbits with amplified immune responses to polysaccharides specific for different streptococcal groups1,2. Levels of group specific antibodies of 50 mg ml−1 have been reported. Such antisera are valuable because they often contain monoclonal antibody which can be used in studies of the origin of antibody diversity. These antibody probes have stimulated a search for variable region markers common to antibodies specific for the same polysaccharide antigen3 and produced by closely related rabbits4,7. In a continuation of earlier marker analyses3 and of a breeding programme for restricted high responders8, we have used the streptococcal group A variant antigen (strain A486 variant of the Rockefeller University) to immunise part-inbred rabbits6,7. This cell wall polysaccharide is a homopolymer of rhamnose9,10 of very limited heterogeneity. We report the partial amino acid sequences of light chains of the b4 allotype isolated from monoclonal antibodies raised in six closely related rabbits after a primary or secondary course of intravenous immunisation with a streptococcal group A variant vaccine6.