Leung HY, Ma CW, Tang QT, Ko KM
 Division of Life Science, Hong Kong University of Science & Technology, Hong Kong SAR, China.  Lee Kum Kee Health Products Group Ltd., Hong Kong SAR, China.
This study aimed to investigate the effects of a compound polysaccharide-based health product (Infinitus Polysac Plus, IPP) on innate and adaptive immunity in mice. Both ex vivo/in vivo mouse models and an in vitro system using cultured mouse splenocytes were adopted for the assessment of innate and adaptive immunity. For the innate immune response, long-term IPP treatment (0.26 and 0.78 g/kg x 20 doses) enhanced the carbon clearance activity and phagocytic rate of macrophages, as well as natural killer cell activity in mice. The IPP-induced increase in natural killer cell activity was accompanied by the suppression of tumor growth in Sarcoma-180 cell-inoculated mice. For the adaptive immune response, while long-term IPP treatment increased the splenocyte index in mice, IPP incubation with mouse splenocytes in vitro potentiated their concanavalin A-stimulated proliferation. Long-term IPP treatment significantly restored the hemolytic activity of serum on sheep red blood cells and dinitrofluorobenezene-induced delayed-type hypersensitivity in sensitized and immunosuppressed mice. In conclusion, the results indicate that long-term IPP treatment produces stimulatory effects on both innate and adaptive immunity in mice.