Inhibition of varicella-zoster virus in vitro by human peripheral blood mononuclear cells.

A functional in vitro assay of cell-mediated immunity to varicella-zoster virus (VZV) is described. This procedure uses an enzyme-linked immunosorbent assay (ELISA) to measure the inhibitory effect of human peripheral blood mononuclear cells on VZV antigen production by VZV-infected cell monolayers. When mononuclear cells from VZV-immune, tetanus-immune donors were stimulated with either VZV antigen or tetanus toxoid they reduced VZV antigen production. In contrast, mononuclear cells from VZV-nonimmune, tetanus-immune donors reduced VZV antigen only when stimulated with tetanus toxoid, but not when stimulated with VZV antigen. Cell-free supernatants recovered from the VZV inhibition assays contained the anti-VZV activity. The magnitude of the anti-VZV activity of the supernatants equalled the inhibition observed when the stimulated mononuclear cells were added to the VZV-infected monolayers. Treatment of either mononuclear cells or supernatants with anti-interferon gamma antibody indicated that their VZV inhibitory capability was largely due to the production of interferon gamma by stimulated mononuclear cells.