A function for human T200 in natural killer cytolysis.

The ability of an antihuman T200 monoclonal antibody, F2.5, to specifically inhibit in vitro human natural killer cell-mediated lysis of K562 target cells is demonstrated. No inhibition by the F2.5 antibody of a cytotoxic T lymphocyte response to autologous virus-infected cells could be shown. Direct binding studies indicated that F2.5 antibody-coated effector cells had a reduced capacity to bind to K562 target cells, suggesting that T200 has a function in the recognition and binding of the natural killer cell to its target cell. This is the first time a role for human T200 and identification of a functional natural killer cell receptor have been described.