FLOW CYTOMETRIC ANALYSIS OF LYMPHOCYTE SUBSETS OF MICE MAINTAINED ON AN ETHANOL-CONTAINING LIQUID DIET

Alcoholic patients often have impaired immune function, yet little is known about the precise mechanism(s) of this impairment. We have previ ously shown that ethanol consumption by mice alters copolymer-specific humoral and cellular immune responses. In this study, we asked whethe r alcohol consumption by mice would phenotypically alter lymphocyte po pulations. Female C57BL/6 mice were fed a nutritionally complete liqui d diet containing 35% ethanol-derived calories for up to 8 days. As co ntrols, mice either were fed a liquid control diet that isocalorically substitutes sucrose for ethanol or remained on a standard solid diet end water ad libitum. Although mice fed ethanol-containing liquid or p air-fed control liquid diets have decreased numbers of spleen cells co mpared with solid diet controls, only the ethanol-containing diet allo wed normally nonresponder C57BL/6 spleen cells to make antibody respon ses to the poly(Glu(50)Tyr(50)) synthetic copolymer antigen. Flow cyto metric analysis of splenic lymphocyte populations of mice on the ethan ol-containing diet shows an increase in the relative proportion of T-l ymphocytes as compared with mice on either solid or liquid control die ts. No such change is seen for either B cell or natural killer cell po pulations in these same mice. Both liquid control and liquid ethanol d iets caused a slight decrease in the CD4:CD8 ratios of splenic T-lymph ocytes. We see the relative percentage of T-cells bearing the alpha be ta T-cell receptor (TcR) increases in the spleens of liquid ethanol di et mice; a smaller increase TcR alpha beta usage is seen in the spleen s of liquid control mice, compared with solid diet mice. Flow cytometr ic analysis shows that little, if any, difference exists in TcR gamma delta expression between the liquid ethanol and either the liquid cont rol or solid diet groups. Preliminary analysis of TcR alpha beta subse ts suggest that ethanol increases the percentage of T-cells expressing V beta 5 and V beta 8, and decreases the percentage of V beta 11 expr essing cells. These findings suggest that, in addition to modifying th e immune response, ethanol alters the phenotypic expression of lymphoc yte subsets.