and number of exposures (not shown). While not conclusive, these data suggest that Spn27A expression regulation by ethanol exposure may utilize this immunity pathway in a manner distinct from bacterial infection. In addition, infection-induced immune responses are limited to the tissues that contact the invading organism, including the tracheal epithelia and the fat bodies that directly interface with the hemolymph. Ethanol, by contrast, diffuses throughout all tissues, and may be able to activate immune response pathways in tissues protected from invaders, such as the brain. Finally, we note that the kinetics of Spn27A transcript accumulation following ethanol exposure are similar to that elicited by infection, suggesting that a similar mechanism of regulating Spn27A levels is engaged by these distinct signals.
