Structure of a Third Murine Immunoglobulin λ Light Chain Variable Region that is Expressed in Laboratory Mice

• Published in: Proceedings of the National Academy of Sciences - PNAS 1987-12, Vol.84 (24), p.9185-9188
• Main Authors: Sanchez, Pierre, Marche, Patrice N., Le Guern, Christian, Cazenave, Pierre-André
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Animals; Antibodies; Antibodies, immunoglobulins; Base Sequence; Biological and medical sciences; Cloning, Molecular; Complementary DNA; DNA probes; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Genes, Immunoglobulin; Genomics; Hybridomas; Immunoglobulin lambda-Chains - genetics; Immunoglobulin Variable Region - genetics; Immunoglobulins; Immunology; Mice; Mice, Inbred Strains - genetics; Molecular immunology; Molecular Sequence Data; Nucleotide sequences; Structure
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.84.24.9185

Recently, we reported evidence for the existence of an immunoglobulin λ light chain (λ x) whose variable region differs from those encoded by the known Vλ gene segments Vλ 1 and Vλ 2. Expression of λ x was detected in some hybridomas elicited by treatment of a BALB/c mouse with rabbit anti-λ 2 antibodies coupled to bacterial lipopolysaccharide [Sanchez, P. & Cazenave, P.-A. (1987) J. Exp. Med. 166, 265-270]. We constructed a cDNA clone from one hybridoma (B6) that expresses the λ x chain and determined the complete nucleotide sequence. The deduced amino acid sequence of Vλ x is 30-33% identical with those encoded by Vλ 1 and Vλ 2 and by Vκ gene segments. The third hypervariable region of Vλ x is four codons longer than those of the other murine variable gene segments. The expression of λ x requires a genomic rearrangement that juxtaposes the Vλ x gene with the Jλ 2-Cλ 2 joining-constant gene pair. Rabbit anti-Vλ x antibodies detected the λ x light chain in the normal sera of all laboratory mice tested. λ x expression seems to be independent of λ 1 expression, since both SJL and SJA strains, which are defective in λ 1 production, express normal levels of λ x chain.