Abstract:

Objective: To explore the effect of polysaccharides from Ganoderma atrum (PSG-1) on the mannose receptor (MR)
of mouse peritoneal macrophages. Methods: After the macrophages were treated with PSG-1 at various concentrations, the
MR expression on the macrophage surface was analyzed by flow cytometry, and then the mRNA expression level of MR was
evaluated by reverse transcription polymerase chain reaction (RT-PCR). After the cells were pretreated with mannan (an MR
inhibitor) and then exposed to PSG-1, the phagocytosis of macrophages was assayed by flow cytometric method, the contents
of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in cell culture supernatant were measured by enzyme-linked
immunosorbent assay (ELISA), and the mRNA expression levels of TNF-α and IL-1β were determined by RT-PCR. Results:
PSG-1 could increase the protein and mRNA expression levels of MR. Compared with the group treated with PSG-1 alone,
the phagocytosis of macrophages and the secretion of IL-1β in cells pretreated with mannan were significantly inhibited
and no effect on the secretion of TNF-α was observed in the presence of PSG-1. Conclusion: MR can partly mediate the
immunoregulatory effect of PSG-1 on peritoneal macrophages in mice. Therefore, MR may be one of the receptors of PSG-1
associated with the immunomodulatory function.

Key words: polysaccharides from Ganoderma atrum, peritoneal macrophages, mannose receptor (MR), phagocytosis, cytokine