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

Abstract

We investigated the ability of human peripheral CD4+ cellsto express CD94 and NKG2 molecules as a consequence ofCD3-mediated activation. Using highly purified peripheralCD4+ T cells, we found expression of both CD94 and NKG2A 15days after CD3-mediated stimulation of cells. We also determined byreverse transcriptase-PCR that all gene members of NKG2 family—namely,NKG2A, -C, -D, and -E—are sequentially expressed on CD4+cells. We found that this expression is tightly regulated by cytokines,and we identified transforming growth factor-β1 and interleukin-10 asthe main factors that, on CD3-dependent stimulation, positivelycontribute to the expression of CD94 and NKG2A on CD4+cells. We also investigated the functional role of NKG2A and found thatcoligation of CD3 and NKG2A by specific monoclonal antibodies resultsin significant inhibition of interferon γ and tumor necrosis factorα production by stimulated CD4+ cells. The presence andfunction of these receptors on CD4+ lymphocytes support amore general role for NKG2 molecules, whose functions were originallythought to be confined to cytotoxic cells, in the immune system.