Immunomodulatory Effects of Peptides from Deer Fetus on RAW264.7 Macrophages

Deer fetus peptides(DFP)was extracted from deer fetus and its immunomodulatory activities in macrophage RAW264.7 was evaluated in vitro. The proliferative activity of each peptide segment in ultrafiltration fraction was determined by methyl thiazolyltetrazolium(MTT)assay,and the components with high proliferative activity were screened. To further evaluate its immunomodulatory activity,the effects of DFP on the phagocytic activity,nitric oxide(NO)and cytokines secretion of RAW264.7 macrophages were detected by inverted microscope observation,neutral red phagocytosis assay and enzyme-linked immunosorbent assay(ELISA),respectively. The effects on the cell cycle distribution of macrophages were also observed. The results showed that DFP-5,with molecula mass less than 1 kDa,could significantly(P<0.05)increase cytokines in RAW264.7 such as nitric oxide(NO),interleukin-1β(IL-1β),interleukin-6(IL-6)and the tumor necrosis factor-α(TNF-α). When the concentration of DFP was 25 μg/mL,the secretion of these factors was the closest to that of the positive control group(LPS). Cell cycle results showed that DFP could promote the proliferation of RAW264.7 cells and the effect was mainly at the G0/G1 phase. All these results indicated that the deer fetus peptide had the potential to activate macrophages and enhance immune function.