Effect of ethanol on natural killer cell activity in vitro

The effect of ethanol on kinetic stages of natural killer (NK) cell activity was studied in vitro. Peripheral blood mononuclear cells (MNC) were either co-cultured or pre-incubated with various ethanol concentrations and assayed for NK cell activity with a "4-hour chromium release assay" and a "single cell cytotoxicity assay in agarose" simultaneously. Direct addition of ethanol to the assay system resulted in a dose-dependent inhibition of NK cell activity. The percentage of lysed conjugated target cells was suppressed from a control value of 21.2% to 17.0%, 15.1%, 11.8% and 10.0% with an ethanol concentration of 0.125%, 0.25%, 0.5% and 1.0%, respectively. NK cell recycling was also inhibited. A 24-hour pre-incubation with ethanol, however, resulted in NK cell activity enhancement. The enhancement was around 20% with a 0.25% ethanol concentration and around 45% with a 0.5% and a 1.0% ethanol concentrations. The enhancing effect was noted mainly at the cytolysis stage after binding of effector cell with target cells.