Abstract:Abstract：To explore the effect of porphyridium creuntum polysaccharide on immunocell functions in vitro.Different concentrations of porphyridium creuntum polysaccharide was used to stimulate the mouse peritoneal macrophage RAW264.7.Lipopolysaccharide（LPS）was used as a positive control.The release of nitric oxide（NO）was detected by griess regent.Cell vitality was determined by MTT method and phagocytic ability was tested by neutral red.The secretion level of tumor necrosis factor-α（TNF-α）and interleukin-6（IL-6）was detected by enzyme-linked immunosorbent（ELISA）.Results showed that different concentrations of polysaccharide could promote the production of NO，and enhance the phagocytosis ability of microphage RAW264.7.The polysaccharide could also stimulate the secretion of TNF-α and IL-6.It was no cytotoxicity when the concentration of porphyridium creuntum polysaccharide was at the rang of 12.5 μg/mL-400 μg/mL.This research preliminary prove that the polysaccharide had immunomodulatory effect on macrophages RAW264.7.This effect on macrophages RAW264.7 would be the basis for further development and application of creuntum polysaccharide polysaccharide.