Definition of the human immunoglobulin variable lambda (IGLV) gene subgroups

Abstract

Comparison of 60 human immunoglobulin variable lambda (IGLV) sequences allowed us to define seven subgroups designated V_λI to V_λVII. We demonstrate that all λ proteins sequenced so far fall into the subgroups I, II, III and VI, and that the λ regions previously assigned to subgroups IV and V belong, in fact, to subgroups III and II, respectively. Four sequences not belonging to any of the subgroups I, II, III and VI define the new subgroups IV, V and VII. Interestingly, these subgroups show a higher homology to rabbit or mouse V_λ genes than to the other human V_λ subgroups. By comparison of the proteins either with the sequences deduced from the germ‐line genes or with the consensus sequences, therate of amino acid changes due to somatic mutations or allelic variations was evaluated in several λ proteins. Framework and complementarity‐determining regions of the human IGLV genes and proteins were delineated. Alignment of the λ sequences shows that functional V‐J rearrangement occurs, with or without deletion of nucleotides encoding one or two amino acids at the 3′ end of the V gene. Diversity of the third complementarity‐determining region is due to somatic mutations and to flexibleV‐J junction, but there is no evidence of N‐diversity in the human λlocus.