Increased susceptibility to human immunodeficiency virus-I (HIV-1) infection, and complications associated with AIDS among alcoholics is widely recognized. The mechanism for increased propensity to infection is thought to be due to ethanol-mediated dysregulation of lymphocyte and monocyte functions. However, studies that deal alcohol-associated changes in vivo in various functions of hepatic macrophages (Kupffer cells) and other phagocytes during HIV-1 infection are few or lacking. Kupffer cells are primarily involved in clearance of particulate and soluble materials (HIV-1 glycoproteins, endotoxin). Thus, any alteration in phagocyte function during viral entry into the host is a major limiting factor in the survival of HIV. Based on these considerations, the overall objective of this proposal is to examine the mechanisms by which alcohol modulates HIV-1 gp120-induced non-specific immune defense mechanisms, i.e., respiratory burst and cytokine release, by Kupffer cells, endothelial cells and neutrophils in the presence or absence of endotoxemia. This proposal is based on the hypothesis that alcohol is a predisposing factor in HIV-1 infection, endotoxemia and liver disease that could hasten its progression to immunodeficiency/AIDS. Specifically, ethanol-induced spontaneous formation of reactive oxygen intermediates (ROI) leads to enhanced TNF and IL-1 production in hepatic macrophages, that could contribute to the immunopathogenesis of HIV-1 infection and AIDS. Proteins derived from HIV-1, e.g., HIV 1 gp12O, may exacerbate cytokine production in the alcoholic liver. Alcohol induces immunodeficiency through attenuation of antigen (HIV 1 gp12O, zymosan)-induced free radical formation in hepatic phagocytes. Thus, specific aim 1 will examine the effect of chronic and acute alcohol intoxication in the rat model (male Sprague-Dawley rats) on HIV-GP-120-induced oxygen-derived free radical formation and cytokine release (IL-1, TNF) by isolated Kupffer cells, endothelial cells, hepatic and blood neutrophils. Since alcohol withdrawal may also have an impact on these cells, studies on superoxide and cytokine release at appropriate interval following withdrawal or recovery from chronic or acute alcohol intoxication will be performed. The relationship between alcohol-mediated alteration of free radical release and cytokine production induced by HIV gpl20 will be studied, by the use of inhibitors of reactive oxygen species, i.e., superoxide dismutase and catalase.
Specific aim 2 will elucidate the effect of alcohol with or without endotoxemia on the activities of protein kinase c and NADPH oxidase and glucose use during HIV-GP-120-(plus PMA or zymosan)-mediated respiratory burst, by analyzing the translocation and activities of these enzymes in cytosolic and membrane fractions of phagocytic cells. HIV GP 120 is currently being tested in one of the major international clinical trials as a potential vaccine against HIV (AIDS). Thus, data that will be generated from these studies will provide important information on the efficacy of HIV GP-120 as a vaccine to stimulate or attenuate non-specific immune functions by phagocytes and its possible adverse side effects in the alcoholic liver.
