Effects of Selenylation Modification on Immune-Enhancing Activity of Garlic Polysaccharide

The garlic polysaccharide was modified by HNO(3)-Na(2)SeO(3) method according to orthogonal design L(9)(3(4)) to obtain nine selenizing garlic polysaccharides, sGPS(1)-sGPS(9). Their effects on chicken peripheral lymphocytes proliferation in vitro were compared by MTT assay. The results showed that sGPSs could significantly promote lymphocytes proliferation, sGPS(3), sGPS(5) and sGPS(6) presented stronger efficacy. In vivo experiment, 14-day-old chickens were injected respectively with sGPS(3), sGPS(5) and sGPS(6) when they were vaccinated with ND vaccine taking unmodified GPS as control. The results showed that three sGPSs could significantly promote lymphocyte proliferation, enhance serum antibody titer, IFN-γ and IL-2 contents. These results indicated that selenylation modification could significantly enhance the immune-enhancing activity of GPS, sGPS(6) possessed the best efficacy and could be as a candidate drug of immunoenhancer. Its optimal modification conditions were 400 mg of sodium selenite for 500 mg of GPS, reaction temperature of 70°C and reaction time of 6 h.