T cell receptor gamma gene status of human alpha/beta+ and gamma/delta+ T cell clones: absence of V9JP rearrangements in alpha/beta+ clones is not a result of a lack of rearrangements involving more 5' J gamma segments.
T cell receptor (TCR) gamma gene rearrangements were examined in panels of human T cell clones expressing TCR alpha/beta or gamma/delta heterodimers. Over half of the alpha/beta+ clones had both chromosomes rearranged to C gamma 2 but this was the case for only 20% of the gamma/delta+ clones. While more than half of the gamma/delta+ clones showed a V9JP rearrangement, this configuration was absent from all 49 alpha/beta+ clones analysed. However, this was not a result of all rearrangements being to the more 3' J gamma genes as 11 alpha/beta+ clones had rearrangement(s) to JP1, the most 5' J gamma gene segment. Both alpha/beta+ and gamma/delta+ clones showed a similar pattern of V gamma gene usage in rearrangements to J gamma 1 or J gamma 2 with a lower proportion of the more 3' genes being rearranged to J gamma 2 than for the more 5' genes. Several alpha/beta+ and several gamma/delta+ clones had noncoordinate patterns of rearrangement involving both C gamma 1 and C gamma 2. Eleven out of fourteen CD8+ clones tested had both chromosomes rearranged to C gamma 2 whereas all clones derived from CD4-8- cells and having unconventional phenotypes (CD4-8- or CD4+8+) had at least one C gamma 1 rearrangement. Twelve out of twenty-seven CD4+ clones also had this pattern, suggesting that CD4-8+ clones had a tendency to utilize more 3' J gamma gene segments than CD4+ clones. There was some evidence for interdonor variation in the proportions of TCR gamma rearrangements to C gamma 1 or C gamma 2 in alpha/beta+ clones as well as gamma/delta+ clones. The results illustrate the unique nature of the V9JP rearrangement in gamma/delta+ clones and the possible use of a sequential mechanism of TCR gamma gene rearrangements during T cell differentiation is discussed.
Christmas
S E
SE
Department of Immunology, Paterson Institute for Cancer Research, Christie Hospital & Holt Radium Institute, Manchester, United Kingdom.
D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens; D002999:Clone Cells; D015334:Gene Rearrangement, gamma-Chain T-Cell Antigen Receptor; D006801:Humans; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000235:genetics*; D016692:Receptors, Antigen, T-Cell, gamma-delta
D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens; D011948:Receptors, Antigen, T-Cell; D016692:Receptors, Antigen, T-Cell, gamma-delta