DESCRIPTION: Excessive alcohol consumption places individuals at higher risk for serious bacterial infections, including those by intracellular pathogens. Observations by this laboratory as well as others indicate that many aspects of macrophage function, including cytokine expression and antigen presentation, are compromised in ethanol consuming individuals. Consequently, this proposal aims to determine if and how macrophages explanted from alcohol-fed mice are more permissive for productive bacterial infection. To most effectively probe the macrophage for alcohol-induced changes, we have incorporated six features into our experimental design. First, we will examine infection by three pathogens which follow distinct intracellular pathways, namely Listeria monocytogenes, Salmonella typhimurium, and Legionella pneumophila. Second, we will assess growth within macrophages from three strains of mice which display different degrees of susceptibility to these bacteria. Third, experiments will only utilize those macrophages which the pathogens encounter in the course of normal infections; e.g., splenic cells for Listeria, and alveolar macrophages for Legionella. Fourth, to more fully illuminate changes in the infection process, we will monitor, at a multiple time points, the numbers of intracellular bacteria, the degree of host cell viability, and the levels of IL-1, IL-6, IL-12, and TNF produced. Fifth, to appreciate the effect of alcohol on innate as well as adaptive immunity, both resident and activated macrophages will be tested for alterations in susceptibility. Finally, we will determine whether the addition of T cells or proinflammatory cytokines, including IFN-gamma, can "reverse" the effect of ethanol. Collectively, the experiments proposed in this R21 application should provide new insight into the molecular and cellular bases of alcohol-induced infectious diseases and lay the foundation for additional, unique lines of inquiry.