Guinea pig immunoglobulin light chain isotypes. I. Separation of kappa and lambda chains and the identification of three isotypes of the lambda chain constant homology region

The primary structure of the constant region of Basilea-rabbit immunoglobulin lambda-chains

The amino acid sequence of the constant region of the immunoglobulin lambda-chain of the rabbit (C lambda) has been determined. This chain was obtained from a homogeneous anti-(type II pneumococcal polysaccharide) antibody fraction raised in Basilea rabbit 4548. The C lambda-region sequence was established by the analysis of tryptic and some overlapping chymotryptic peptides and partly by homology with known C lambda-region sequences of lambda-chains from other species. Peptides were isolated by a combination of methods including high-voltage paper electrophoresis, gel filtration and high-pressure liquid chromatography. The peptides were subjected to automated Edman degradation in the presence of Polybrene. The sequence showed no evidence of heterogeneity. Large interspecies similarities, as well as amino acid interchanges, are apparent among various C lambda regions; the degrees of homology between rabbit C lambda region and the C lambda region from human, porcine and murine chains are 72.6, 71 and 72% respectively. The similarity of lambda-chains of different species is much greater than that found between rabbit kappa- and lambda-chains (about 34% homology). Genetic implications of these results are discussed.

Guinea pig immunoglobulin light chain isotypes. II. The preferential expression of lambda chain-bearing anti-phenyltrimethylammonium antibodies is associated with restricted variable region expression, but not with any alteration in the proportion of lambda chain constant region isotypes, relative to normal immunoglobulins

The inbred strain 13 guinea pig expresses at least three isotypes of immunoglobulin (Ig) lambda chain. The proportion of these isotypes in normal Ig can be estimated by isolating a constant (C) region cyanogen bromide peptide from lambda chains and quantitatively analyzing its component tryptic peptides. Anti-phenyltrimethylammonium antibody, when analyzed in this way, was found to contain the same proportion of each lambda chain C region isotype as did normal Ig. The specific antibody light (L) chain pools were found to contain predominantly lambda chains, although these are the minority type in guinea pig normal Ig L chain pools. Moreover, amino-terminal, 5-pyrrolidone-2-carboxylic acid-containing peptides isolated from antibody lambda chains show no demonstrable sequence heterogeneity, while their homologs isolated from normal lambda chains are markedly heterogeneous. That a restriction in heterogeneity of variable region framework residue positions is not associated with any alteration in the proportion of C region isotypes in these antibody lambda chains, implies that translocation of all guinea pig lambda chain variable region genes to the isotypic C region genes occurs in a random way.