Amino acid sequences of antibody light chain variable regions of pedigreed rabbits: kappa light chain K49-501 (allotype b4 anti-streptococcal group A-variant polysaccharide antibody).

The amino acid sequence of positions 1--150 of a light chain, isolated from another monoclonal rabbit anti-streptococcal group A-variant polysaccharide antibody, was determined. The analysis was performed with 2 mumol of polypeptide chain, using a grossly modified Beckman 890B sequenator. This sequence stretch accounts for the whole variable region and a considerable part of the constant region at a total length of 218 amino acids. This allotype b4 light chain was isolated from a non-precipitating, end-group-specific antibody with a KD = 1.3 X 10(-5)M. This brings the present number of totally known rabbit VL sequences of antigen elicited antibodies to 21. A comparison of these 21 sequences reveals a building plan of ribbit VL homologous to that of human and murine VL regions. The observed variability does follow a pattern of linked amino acid substitutions, indicating that this information must be contained in the germ-line of the rabbit in the form of multiple VL region genes. This conclusion, however, does not rule out the occasional variant being due to somatic rearrangement. Finally, this comparison reveals that the joining peptide between positions 96--110 is also a separate entity in rabbit VL region sequences.