Partial sequence of the variable region of IgG light chains of b5 allotype from a [formula omitted] rabbit

Abstract

The partial sequence (positions 29–71) of the variable region of light chains of predominately b5 allotype from the IgG of a single allotype-suppressed rabbit was obtained by traditional sequencing methods on isolated tryptic and chymotryptic peptides. The peptides from this region were isolated in relatively high yields and probably represent a dominant sequence. The framework sequence between positions 35 and 49 (FR 2) is identical to an FR 2 sequence commonly found in light chains from antibodies produced by b4 rabbits as well as murine and human myeloma light chains, with the exception of an interchange of threonine for proline at position 43 or 44. This may be b5 allotype-related since, to date, all the b4 light chains have had proline, and a b9 light chain was found with arginine at position 43. The fact that a dominant sequence could also be found for positions corresponding to the second complementarity determining region (CDR 2, 50–56) in other species, confirms previous observations that this portion of the light chain is not extremely variable in the rabbit.