Different effects of ethanol on particle phagocytosis via different receptors in human monocytes

Abstract

Endocytosis of test particles by human blood monocytes (Mo) was tested in the presence of ethanol (80 mM). Phagocytosis via the Fc (IgG)- or C3b receptors (R) was assessed by an assay in which IgG- or C3b coated sheep erythrocytes (E) were used as test particles. Latex particles were tested in parallel with opsonized E. Phagocytosis of IgG-E was reduced to 67 +/- 5% of control (= without ethanol), while the corresponding value for C3b-E was 164 +/- 26% controls. Phagocytosis of latex particles was not affected by ethanol exposure (91 +/- 8% of control). The receptor functions were also tested without ethanol present during the assays. In this part of the study, Mo were incubated with or without ethanol in autologous serum for 15 min at 37 degrees C. After washing the cells free of ethanol, binding properties of the Fc-R or C3b-R were assessed by a rosette assay. Preincubation with ethanol reduced Fc-R binding, while attachment to C3b-R seemed to be more effective. The experiments thus indicate different effects of ethanol treatment in vitro on phagocytic receptors in human Mo. Control experiments revealed no direct effect of ethanol on the test particles.