Functional immunoglobulin light chain genes are replaced by ongoing rearrangements of germline V kappa genes to downstream J kappa segment in a murine B cell line.
A murine B cell lymphoma (38C13) was subjected to immunoselection with mAbs directed against the idiotypic determinants of its cell surface Ig. Variants emerged with altered Ig receptors containing identical heavy chains but different light chains. The functional light chain genes in these variants were composed of V kappa segments drawn from the V kappa Ox-1 family, which had replaced the V kappa gene expressed by the parental tumor by rearranging to downstream J kappa segments. Rearrangement at the kappa locus continued to occur spontaneously, giving rise to secondary and tertiary variants at a rate of 1.9 x 10(-4) per cell per generation. Variants were isolated that had ceased production of surface Ig but went on to rearrange again and to become surface Ig+. The Ig- state may be an intermediate step providing a stimulus for continued rearrangement. This process provides an additional mechanism for generating diversity within B cell clones and expands the use of the available repertoire of Ig genes.
Levy
S
S
Department of Medicine, Stanford University School of Medicine, California 94305.
Campbell
M J
MJ
Levy
R
R
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology*; D001483:Base Sequence; D002460:Cell Line; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain; D005803:Genes, Immunoglobulin; D007130:Immunoglobulin Idiotypes / Q000235:genetics; D007133:Immunoglobulin Joining Region / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D007135:Immunoglobulin Variable Region / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D014158:Transcription, Genetic
D007130:Immunoglobulin Idiotypes; D007133:Immunoglobulin Joining Region; D007147:Immunoglobulin Light Chains; D007135:Immunoglobulin Variable Region