T-Cell Receptor β -Chain Expression: Dependence on Relatively Few Variable Region Genes
Abstract
Fifteen independently isolated complementary DNA clones that contain T-cell receptor (TCR) Vβ genes were sequenced and found to represent 11 different Vβ genes. When compared with known sequences, 14 different Vβ genes could be defined from a total of 25 complementary DNA's; 11 clones therefore involved repeated usage of previously identified Vβ's. Based on these data, we calculate a maximum likelihood estimate of the number of expressed germline Vβ genes to be 18 with an upper 95 percent confidence bound of 30 genes. Southern blot analysis has shown that most of these genes belong to single element subfamilies which show very limited interstrain polymorphism. The TCR β -chain diversity appears to be generated from a limited Vβ gene pool primarily by extensive variability at the variable-diversity-joining (V-D-J) junctional site, with no evidence for the involvement of somatic hypermutation.
- Publication:
-
Science
- Pub Date:
- August 1985
- DOI:
- 10.1126/science.3875151
- Bibcode:
- 1985Sci...229..566B