ADJUVANT EFFECT OF GRIFOLAN ON ANTIBODY-PRODUCTION IN MICE

The effects of grifolan (GRN), a gel-forming (1-->6)-branched (1-->3)- beta-D-glucan, on antibody production were examined. Sera from mice th at were injected with GRN and trinitrophenyl ovalbumin (TNP-OVA) intra peritoneally showed a significantly increased level of anti-TNP IgG. H owever, injection of TNP-OVA alone showed a lower antibody level. Two hundred fifty mu g of GRN and 10 mu g of TNP-OVA gave the maximum prod uction of anti-TNP antibody. Enhanced antibody production was also obs erved in the culture supernatant of splenocyte obtained from GRN-admin istered mice. The culture supernatant contained a significant amount o f nitric oxide (NO) in the case of GRN-administered mice. To observe t he effect of NO on the antibody production induced by GRN, N-monomethy l arginine (NMMA), an inhibitor of NO synthetase, was added to the spl enocyte cultures. The antibody level of supernatants containing NMMA w as higher than that of control supernatants. These results suggest tha t GRN can enhance antibody production and that NO induced by stimulati on with GRN concomitantly with antibody production is a negative facto r on the adjuvant activity. Inhibition of NO may increase the adjuvant effect of GRN.