Intrachain disulphide bridges of rabbit immunoglobulin light chains of allotypes b4 and b5.

The study of rabbit H-chain allotypes has provided important insights into the genetic control ofimmunoglobulin synthesis. For example, the V regions of the H-chains, which are governed by the a locus, are not class (C region)-specific (Todd, 1963; Wilkinson, 1969), and genetic markers in the C region of the y-chain are closely linked to the a locus (Landucci Tosi et al., 1970; Kindt et al., 1970). As far as rabbit L-chains are concerned, the amino acid sequences at the C-termini are known to be related to allotypes controlled by the b locus (Appella et al., 1969; Frangione, 1969), and we and others have been attempting to find additional allotype-related sequences in rabbit K-chains (Frangione & Lamm, 1970; Hood et al., 1971; Chersi et al., 1971). Aside from correlations with allotype, the primary structure and folding of rabbit L-chains are of interest from other viewpoints in addition to their obvious relationship to antibody specificity. Thus the intrachaindisulphide-bridge regions of immunoglobulins appear to have been conserved during evolution and are thought to be important determinants of folding (Milstein et al., 1967; Edelman & Gall, 1969; Poljack et at., 1972). In this regard, however, rabbit