Natural killing of cytomegalovirus-infected fibroblasts by human mononuclear leucocytes.

The ability of human peripheral blood mononuclear (MN) cells to lyse uninfected and cytomegalovirus (CMV) infected human fibroblasts was determined in a 51Cr-release assay. Maximal release was obtained with 6-day infected fibroblasts incubated with MN cells for 24 hr. A linear relationship existed between E/T ratios of 12.5:1 to 100:1 and lysis of CMV-infected targets. Donor immune status had no effect on the magnitude of killing of infected or uninfected targets. Killing was mediated by non-B, predominantly non-T, Fc receptor-bearing cells. Preincubation of effector cells with interferon enhanced killing of both CMV-infected and uninfected fibroblasts, but infected targets were more effectively killed. These results indicated a possible role for natural killer cells in recovery from CMV infection.