Actin mediates secretory immunoglobulin A transport: effect of ethanol

Secretory immunoglobulin A (IgA) is the principle antibody protecting against pathogens at mucosal sites. Ethanol (EtOH) exposure is related to adverse effects on the enterocyte cytoskeleton. The aim of this study was to assess the role of normal cytoskeletal function on IgA transcytosis and its modulation by EtOH by studying Madin-Darby canine kidney (MDCK) cells transfected with the polyimmunoglobulin receptor. MDCK cells were grown as confluent monolayers and treated with 5 per cent EtOH, cytochalasin D (Cyto-D, a cytoskeletal destabilizer), or pretreatment with prostaglandin E2 (a cytoskeletal stabilizer) followed by EtOH. Media alone served as control. IgA was then added to the basolateral side of the chambers, and apical samples were taken for enzyme-linked immunosorbent assay analysis at 0, 3, and 12 hours. Dimeric IgA transcytosis increased in all groups and was significantly depressed by 5 per cent EtOH and Cyto-D. Morphological slides revealed aggregation of actin after Cyto-D treatment. Prostaglandin E2 prevented the decrease in IgA transcytosis seen otherwise with 5 per cent EtOH treatment. We conclude that IgA transcytosis is dependent on actin microfilaments of the cytoskeleton. Decreased IgA transport may lead to mucosal immunodeficiency and infectious complications after EtOH exposure.