Chronic ethanol, B cell competence and lymphoid integrity

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Long-temn alcohol consumption progressively leads to multiple immune defects. Chronic alcoholics display lesions in both innate and adaptive immunity, and experience increased rates of bacterial and viral infection. Of particular interest, extended alcohol intake leads to abnormalities within the B cell compartment with reduced B cell numbers, poor antibody (Ab) responses and aberrant regulation. In addition to immune deficiency caused by extended ethanol intake, children with fetal alcohol syndrome (FAS) also display immunologic deficits and higher infection rates. Given the inherent difficulties in studying alcoholic patients and FAS children, the utilization of animal models is essential to understand the extent of immune dysfunction after alcohol exposure, and the means by which ethanol mediates damage. In order to better mimic chronic alcoholism, as well as fetal alcohol exposure, we have exploited the ethanol-in-drinking-water mouse model that allows for long-term alcohol consumption without nutritional deprivation or systemic stress Importantly, after months of ethanol intake, mice exhibit multiple immune abnormalities including reduced B cell numbers in the peripheral lymphoid organs and compromised Ab responses. Of interest, these lesions are accompanied by progressive disruption of lymphoid integrity in the spleen, suggesting alcohol to induce structural damage within secondary lymphoid tissues. Using the ethanol-in-drinking-water model we have also successfully bred mice and brought them to term with minimal loss of pups. While remaining on ethanol, the females nursed the same pups allowing for alcohol exposure during the entire gestational and neonatal period. After reaching adulthood, these fetal/neonatal ethanol mice exhibited both physical and functional immune lesions. Using this model, studies in this proposal will explore the means by which ethanol damages peripheral lymphoid organs, whether adaptive immunity recovers after withdrawal arid if fetal/neonatal ethanol exposure leads to permanent immune lesions. Aim 1 will therefore investigate which mechanisms essential for secondary lymphoid organization are disrupted after long-term ethanol intake. Aim 2 will test the hypothesis that oxidative stress induced by alcohol triggers damage in secondary lymphoid tissue. Aim 3 will test the hypothesis that withdrawal from ethanol after extended consumption will lead to only partial recovery of immune function. Aim 4 will test the hypothesis that alcohol exposure during development leads to pemnanent damage within secondary lymphoid organs and life-long immune deficiency. All four Aims will primarily focus on the status of lymphoid integrity and B cell competence. Chronic alcohol abuse leads to significant lesions in adaptive immunity with accompanying mortiidity and mortality. FAS children likewise experience immune deficiency and increased rates of infection. The proposed studies will offer novel insights into the mechanisms by which long-term alcohol exposure injures the adaptive immune system, and whether potential therapies can be designed to help reverse damage and recover immune function.