Demonstration of the antiviral role of natural killer cells in vivo with a natural killer cell-specific monoclonal antibody (NK 1.1).

A monoclonal antibody (NK 1.1) to mouse natural killer (NK) cells selectively depleted NK cell activity in virus-infected mice without significantly depressing other immune functions, including the development of virus-specific cytotoxic T cells. NK cell depletion with this antibody resulted in markedly enhanced plaque-forming unit titers of some (murine cytomegalo, Pichinde) but not other (mouse hepatitis, lymphocytic choriomeningitis) viruses. This confirms that NK cells do play a role in regulating certain infections and shows that this antibody provides a convenient tool for examining the role of NK cells in viral infections.