DIETARY FATTY-ACID MODULATES ACTIONS OF NUCLEOTIDES ON HUMORAL IMMUNE-RESPONSES

Polynucleotides enhance T cell-dependent antibody production in cultur e. Impaired antibody production in mice fed a nucleotide-free diet can be easily restored by in vivo supplementation of both a mononucleotid e-nucleoside mixture (OG-VI) and polynucleotides. Polynucleotides appe ar to act partly by modulating antigen presentation processes mediated by cell surface molecules. We examined whether dietary fatty acid man ipulation alters nucleotides' actions on humoral immunity. Antibody pr oduction was studied in C57B1/6 mice fed I) a nucleotide-free diet hig h in saturated fatty acid (SFA diet), 2) a nucleotide-free diet high i n polyunsaturated fatty acid (PUFA diet), and 3) a regular nucleotide- free diet (control). In vivo and in vitro T cell-dependent antibody pr oduction decreased in all groups, but mice fed the SFA diet produced m ore antibody in vivo than did mice in the other diet groups. Spleen ce lls from mice fed the SFA diet also produced more interferon-a when st imulated with mitogens than did those from mice fed the control diet. In contrast, polynucleotides enhanced in vitro antibody production muc h less efficiently in mice fed the SFA diet than in the other mice and in vivo supplementation of OG-VI was also less effective in restoring impaired antibody production in these mice. A diet with a high conten t of SFA may alter nucleotides' action on humoral immune responses, in addition to its direct effects on immune functions.