Synthesis of lambda light chain subtypes by stimulated and unstimulated mouse B cells.
Inbred mouse make 3 lambda chain subtypes. The lambda 1 and lambda 3 chains have similar variable (V) regions (in both the same V gene segment [V lambda 1] is used), whereas lambda 2 and lambda 3 have similar constant (C) regions. Despite the lambda 1 and lambda 3 V region similarity, lambda 1 occurs much more frequently than lambda 3 (and lambda 2) in the serum immunoglobulins and antibody responses of most inbred strains of mice. To explore the basis for the lambda 1 predominance, we compared the rates of synthesis of the 3 subtypes and the frequencies of the B cells that synthesize them, focussing on "resting" (i.e., unstimulated) and on polyclonally stimulated B cells from spleens of unimmunized BALB/c mice. In resting cells the relative rates of synthesis and the relative frequencies of the respective B cells were in accord, indicating that the rate of lambda chain synthesis is approximately the same per resting B cell, regardless of the lambda subtype it produces. However, in the polyclonally stimulated cells, lambda 1 was made 7 times faster than lambda 2 and 10 times faster than lambda 3; normalizing these rates by the frequencies of the respective stimulated cells suggests that in stimulated B cells lambda 1 chains are made 5 times faster per cell than lambda 2 or lambda 3, while the latter are made at about the same rate per cell. In view of the marked structural homology between lambda 2 and lambda 3 genes in segments other than the V-gene segment, we suggest that the pronounced differences among polyclonally stimulated B cells in expression of the genes for the various lambda subtypes may be due to the presence of less potent enhancer-like sequences in the lambda 2 and lambda 3 genes than in the lambda 1 gene.
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D003208:Concanavalin A / Q000494:pharmacology; D007143:Immunoglobulin Heavy Chains / Q000032:analysis; D007147:Immunoglobulin Light Chains / Q000096:biosynthesis*; D007146:Immunoglobulin lambda-Chains / Q000032:analysis / Q000096:biosynthesis* / Q000145:classification; D007700:Kinetics; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008815:Mice, Inbred Strains; D011947:Receptors, Antigen, B-Cell / Q000032:analysis; D014415:Tunicamycin / Q000494:pharmacology
D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D007146:Immunoglobulin lambda-Chains; D011947:Receptors, Antigen, B-Cell; D003208:Concanavalin A; D014415:Tunicamycin