Immunoglobulin V regions and the B cell.
There is now substantial evidence that a small group of V genes predominates in the Ig repertoire of preimmune B cells. This phenomenon of V gene restriction may reflect preferential accessibility of these genes to recombinase, homology-directed V gene rearrangement, promoters and enhances of V gene transcription, or positive and negative selection mediated by the anti-self binding properties of the B cells surface Ig. These mechanisms may operate alone or in combination to influence V gene rearrangement and populations of immature B cells. Although constraints on the pool of rearranged V genes may seem disadvantageous to the immune system, the mechanisms that generate the CDR3s of heavy and light chains ensure extensive diversity in the pre-B-cell population. In mature B cells, somatic mutation of V genes adds further diversity. CDR3 sequences and somatic mutations not only provide potentially useful clonal markers but also help to identify the normal counterparts of malignant B cells.
Stewart
A K
AK
Division of Hematology-Oncology, Toronto Hospital, Ontario, Canada.
Schwartz
R S
RS
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology*; D015321:Gene Rearrangement; D005803:Genes, Immunoglobulin; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000235:genetics*
D007135:Immunoglobulin Variable Region