A unique V-J-C-rearranged gene encodes a gamma protein expressed on the majority of CD3+ T cell receptor-alpha/beta- circulating lymphocytes.
We have recently described an mAb, anti-Ti gamma A, that recognizes an antigenic determinant carried by a TCR gamma chain. This antibody binds to approximately 3% of human PBLs and delineates a CD2+, CD3+, TCR-alpha/beta-, CD4-, CD8+/-, CD5+, NKH1-, and HLA class II- subset. The present study was designed to identify the gene encoding the Ti gamma A epitope. A first analysis was carried out on a previously characterized TCR gamma + fetal-cloned cell line termed F6C7. It was found that F6C7 cells have one gamma rearrangement on each chromosome: one joins V gamma 3 to J gamma 1, and the second joins V gamma 9 to J gamma P. Because only the latter allele appeared to be transcribed in the F6C7 lymphocytes, these data strongly suggested that anti-Ti gamma A mAb is specific for either a V gamma 9 or a V gamma 9-J gamma P-encoded peptide. To confirm this point, we studied an additional series of 13 randomly selected Ti gamma A+ cloned cells derived from peripheral blood of three distinct adult individuals. Each one of these lymphocytes was shown to both possess and transcribe a V gamma 9-J gamma P-C gamma 1-rearranged gene. It is therefore concluded that a predominant subpopulation of CD3+ TCR-alpha/beta- human circulating T lymphocytes (namely, the subset defined by anti-Ti gamma A mAb) surface expresses a gamma protein with a limited potential of variability from one cell to another.
D000328:Adult; D000945:Antigens, Differentiation, T-Lymphocyte / Q000235:genetics*; D002460:Cell Line; D000939:Epitopes / Q000235:genetics; D005796:Genes; D006801:Humans; D009154:Mutation; D009693:Nucleic Acid Hybridization; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000235:genetics* / Q000302:isolation & purification; D011995:Recombination, Genetic; D013601:T-Lymphocytes / Q000145:classification* / Q000378:metabolism; D014158:Transcription, Genetic
D000945:Antigens, Differentiation, T-Lymphocyte; D000939:Epitopes; D011948:Receptors, Antigen, T-Cell