Underutilization of the V kappa 10C gene in the B cell repertoire is due to the loss of productive VJ rearrangements during B cell development.
The V kappa10 family of murine light chain Ig genes is composed of three members, two of which (V kappa 10A and V kappa 10B) are well used. V kappa 10C, the third member of this family, is not detected in any expressed Abs. Our previous work showed that V kappa 10C is structurally functional and can recombine, but mRNA levels in spleen were extremely low relative to those of V kappa 10A and V kappa 10B. Furthermore, while the V kappa 10C promoter was efficient in B cells, it was shown to work inefficiently in pre-B cell lines. Here, we extend our analysis of the V kappa 10 family and examine V kappa 10 gene accessibility, their representation in V kappa cDNA phage libraries, and the frequency and nature of rearrangements during different stages of B cell development. We demonstrate that V kappa 10C is under-represented in V kappa cDNA libraries, but that the frequency of its sterile transcripts in pre-B cells surpasses both V kappa 10A and V kappa 10B, indicating that the gene is as accessible as V kappa 10A and V kappa 10B to the recombination machinery. We also demonstrate that V kappa 10C recombines at a frequency equal to that of V kappa 10A in pre-B cells and has a normal nonproductive to productive recombination ratio. As B cells develop, however, both the frequency of V kappa 10C rearrangements and the presence of productive rearrangements decline, indicating that these cells are in some fashion being eliminated.
Fitzsimmons
S P
SP
Division of Monoclonal Antibodies and Division of Cellular and Gene Therapies, Food and Drug Administration, Center for Biologics Evaluation and Research, Rockville, MD 20852, USA. fitzsimmons@cber.fda.gov
Clark
K J
KJ
Mostowski
H S
HS
Shapiro
M A
MA
D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D002454:Cell Differentiation / Q000235:genetics / Q000276:immunology; D002469:Cell Separation; D005260:Female; D015322:Gene Rearrangement, B-Lymphocyte; D005803:Genes, Immunoglobulin; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000235:genetics*; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis / Q000235:genetics*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D005810:Multigene Family / Q000276:immunology; D011995:Recombination, Genetic / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D014158:Transcription, Genetic / Q000276:immunology
D007135:Immunoglobulin Variable Region; D007145:Immunoglobulin kappa-Chains