IN-VITRO EFFECTS OF ETHANOL ON POLYMORPHONUCLEAR LEUKOCYTE MEMBRANE-RECEPTOR EXPRESSION AND MOBILITY

The hampered inflammation and host defense seen in alcoholics may be d ue to impairment of functional responses of neutrophil polymorphonucle ar leukocytes (PMN). We have shown that ethanol inhibits the oxidative metabolism of PMN induced by surface receptor dependent stimuli, such as N-formyl-methionyl-leucyl-phenylalanine (fMLP) and opsonized zymos an. Because the unresponsiveness might be due to reduced numbers of su rface receptors, we assessed the expression of CR1, Fc-gamma, and fMLP receptors as well as membrane fluidity after treatment of PMN with et hanol in vitro. Ethanol impaired the induced expression of CR1 and fML P receptors to 71% and 51% of control, respectively, but did not affec t the resting level of CR1 nor Fc-gamma receptor expression. Furthermo re, the mobility of cell membrane glycoconjugates was increased by eth anol. However, phagocytosis, a functional response dependent on membra ne rheology, was unaffected. Because the results indicated an effect o f ethanol on mobilization of receptors from intracellular stores, we a ssessed lactoferrin release, which was reduced to 59%. Thus, ethanol a ppeared to hamper the upregulation of PMN surface receptors or functio nal subsets of those stored in granules. Ethanol also increased the mo bility of the cell membrane. These reactions were accompanied by reduc tions in the functional responses mediated by either class of receptor s.