V(GAMMA) GENE USAGE IN PERIPHERAL-BLOOD GAMMA-DELTA T-CELLS

The majority (50-90%) of gammadelta T cells in the peripheral blood of adult individuals expresses a T-cell receptor (TCR) which uses Vgamma 9 and Vdelta2 as variable elements. Little is known about the distribu tion of other Vgamma gene elements in the remaining 10-50% of gammadel ta T cells. Here we have studied the Vgamma gene expression in periphe ral blood gammadelta T cells by 3-color flow cytometry analysis applyi ng established monoclonal antibodies (mAb) directed against Vgamma9 an d Vgamma4, as well as a novel mAb directed against Vgamma2, Vgamma3 an d Vgamma4. On average, 79.9% of gammadelta T cells expressed Vgamma9, 11.9% Vgamma2/Vgamma3, 4.4% Vgamma4, and 7.5% one of the remaining Vga mma5, Vgamma8, Vgamma10 or Vgamma11 elements. There were remarkable va riations in the gammadelta subset composition between individual donor s. The majority (69.8%) of Vgamma2/Vgamma3/Vgamma4-bearing cells co-ex pressed Vdelta1, while on average only 17.8% of Vgamma2/Vgamma3/Vgamma 4-bearing cells co-expressed Vdelta2. This is in contrast to Vgamma9-b earing gammadelta T cells, of which 83.1% used Vdelta2 and only 12.7% Vdelta1. Taken together, this data identifies Vgamma2/Vgamma3 as the s econd most frequently used set of Vgamma elements in human peripheral blood gammadelta T cells.