Various studies have explored the role of CD14 and TLR4, receptors of LPS, in chronic alcohol-induced sensitization to LPS-induced liver injury (21, 22) as well as in acute alcohol induced immune functions (4, 17). Because acute alcohol exposure of human monocytes reduces, whereas chronic alcohol exposure augments, LPS-induced TNF-α production, next we determined whether alcohol exposure of human monocytes for 1 day or 7 days had any effect on CD14 and TLR4 expression. Fig. 2A shows that acute (1 day) and chronic alcohol (7 days) exposure did not alter surface expression of CD14 and TLR4 as analyzed by flow cytometry, suggesting that acute and chronic alcohol mediated changes in TNF-α production is independent of surface receptor expression on human monocytes.
