T cell-macrophage interactions in the immune response to herpes simplex virus: the significance of interferon-gamma.

The antiviral properties of a herpex simplex virus type 1-specific 'helper' T cell clone were investigated. The clone was found to be deficient in interleukin 2 production, although it produced interleukin 3 and interferon-gamma upon stimulation with the virus in vitro. Supernatants containing these lymphokines were observed to increase the virocidal activity of macrophages in vitro and furthermore induced these cells to mediate cytotoxic activity against virus-infected target cells. Macrophage activation was linked to the presence of interferon-gamma in the clone supernatant. The implications of these results for protection against this virus in vivo are discussed.