Abstract: Fungal immunomodulatory proteins (FIPs) have immunomodulatory and anti-tumor effects. Macrophages play an important role in tumor immunotherapy, and M1 type macrophages have strong tumor killing ability and antigen presentation ability. This study aimed to explore the effect and underlying mechanism of FIPs on the in vitro activation of macrophage RAW264.7 cells into M1 type. After being treated with a recombinant Ganoderma atrum immunomodulatory protein (rFIP-gat), the phagocytosis ability of RAW264.7 cells was determined by neutral red uptake assay, and nitric oxide (NO) production by a nitric oxide detection kit. Quantitative real-time polymerase chain reaction (qPCR) was used to determine the relative expression levels of tumor necrosis factor-α (TNF-α) and inducible nitric oxide synthase (iNOS) genes. The results indicated that rFIP-gat enhanced phagocytosis, promoted the production of nitric oxide, and increased the transcription of iNOS and TNF-α in macrophage RAW264.7 cells in a dose-dependent manner. In conclusion, rFIP-gat may induce the differentiation of macrophage RAW264.7 cells into M1 type.

Key words: recombinant Ganoderma atrum immunomodulatory protein, macrophage RAW264.7, tumor necrosis factor-α, inducible nitric oxide synthase