Effects of ethanol on parameters of cellular immunity and host defense mechanisms to infectious agents

Results of several studies have associated ethanol abuse with an increased incidence of infections, including opportunistic infections and those caused by microorganisms, as well as of certain types of cancer. Research findings from several laboratories clearly indicate that one possible mechanism in this association is an effect of ethanol on the immune system. We have developed an animal model of ethanol ingestion in a liquid diet to study the effects of ethanol on immune responses. In most of the studies, we have used a pair-feeding design in which control animals are given a liquid diet that is isocaloric to the ethanol diet by the addition of either sucrose or dextran-maltose. Here, we discuss data obtained from in vivo studies of cellular function. We have studied the effects of ethanol on activation of T lymphocytes in vivo after intravenous injection of monoclonal antibody to CD3. The stimulation of cells in the spleen was assessed by measuring levels of cytokine RNA. We have also assessed the ability of animals to respond to a sublethal dose of Listeria monocytogenes to determine whether ethanol alters host defense mechanisms. Our findings indicate that ethanol ingestion reduced the ability of mice to respond to anti-CD3 and to resist infection with a bacterium that predominantly infects the liver.