Induction of CD94/NKG2A expression on T cells in mixed lymphocyte culture by CD14+ cells from granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cells.

We report the increased expression of inhibitory natural killer (NK) cell receptor, CD94/NKG2A, for human leucocyte antigen (HLA) class I on CD8+ T cells in granulocyte colony-stimulating factor-mobilized peripheral blood mononuclear cells (G-PBMC) after mixed lymphocyte culture (MLC). The addition of purified CD14+ cells to CD14-depleted G-PBMC-induced CD94/NKG2A expression in a dose-dependent fashion; however, this enhancing effect was inhibited by the membrane between responder cells and CD14+ cells. Therefore, CD14+ cells in G-PBMC induce CD94/NKG2A expression on CD8+ T cells, which in turn appear to downregulate alloresponses after allogeneic peripheral blood stem cell transplantation.