In vitro effect of acetaldehyde on cell-mediated cytotoxicity by murine spleen cells

The effects of acetaldehyde in vitro on the lytic capacity of murine spleen cells have been evaluated in three systems: antibody-dependent cell-mediated cytotoxicity (ADCC), natural killer (NK) activity, and alloimmune cytotoxic T lymphocyte (CTL) activity. Acetaldehyde had a biphasic effect on ADCC. Concentrations less than 1 mM acetaldehyde potentiated ADCC. Concentrations greater than 1 mM produced a progressive decrease in lysis. The inhibitory effects were at the effector cell level and were partially irreversible. Preincubation experiments showed that inhibition of ADCC was both concentration and time-dependent. Preincubation of the spleen cells for short periods of time produced potentiated lysis by concentrations of acetaldehyde up to 10 mM. However, potentiation of lysis in preincubation and short term (4h) lytic assay experiments was more variable than longer term (18h) experiments in which the acetaldehyde was not removed by washing. NK activity and alloimmune CTL-mediated lysis were also inhibited by acetaldehyde. Concentrations of acetaldehyde up to 20 mM did not significantly decrease lymphocyte viability as determined by trypan blue exclusion. Acetaldehyde was lost from the reaction mixtures by first order kinetics with a rate constant of 0.5/hr. Thus, the final concentrations were 64-99.99% lower than the starting amounts.