Expression of CD94 and NKG2 molecules on human CD4(+) T cells in response to CD3-mediated stimulation

We investigated the ability of human peripheral CD4(+) cells to express CD9 4 and NKG2 molecules as a consequence of CD3-mediated activation. Using hig hly purified peripheral CD4(+) T cells, we found expression of both CD94 an d NKG2A 15 days after CD3-mediated stimulation of cells. We also determined by reverse transcriptase-PCR that all gene members of NKG2 family-namely, NKG2A, -C, -D, and -E - are sequentially expressed on CD4(+) cells. We foun d that this expression is tightly regulated by cytokines, and we identified transforming growth factor-beta1 and interleukin-10 as the main factors th at, on CD3-dependent stimulation, positively contribute to the expression o f CD94 and NKG2A on CD4(+) cells. We also investigated the functional role of NKG2A and found that coligation of CD3 and NKG2A. by specific monoclonal antibodies results in significant inhibition of interferon gamma and tumor necrosis factor at production by stimulated CD4(+) cells. The presence and function of these receptors on CD4(+) lymphocytes support a more general r ole for NKG2 molecules, whose functions were originally thought to be confi ned to cytotoxic cells, in the immune system.