1,3-β-glucan affects the balance of Th1/Th2 cytokines by promoting secretion of anti-inflammatory cytokines in vitro.

1,3-β-glucan is considered a fungal biomarker and exposure to this agent induces lung inflammation. Previous studies have shown that 1,3-β-glucan affects Th1 and Th2 immune responses. Interleukin (IL)-10 and transforming growth factor (TGF)-β, as typical anti-inflammatory cytokines, suppress the Th1 immune response. To investigate the effects of 1,3-β-glucan on the secretion of cytokines in co-cultured mouse macrophages and lymphocytes in vitro, mice were exposed to 1,3-β-glucan or phosphate-buffered saline (PBS) by intratracheal instillation. Following extraction and co-culture of macrophages and lymphocytes, which were treated with or without 1,3-β-glucan in vitro, enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of cytokines and real-time reverse transcription (RT)-polymerase chain reaction (PCR) was used to investigate the mRNA expression of forkhead box p3 (Foxp3) in the cells. We showed that 1,3-β-glucan exposure in vitro decreased the secretion of Th1 cytokines and increased the secretion of Th2 cytokines in the culture media. Furthermore, 1,3-β-glucan exposure in vitro increased the secretion of IL-10 and TGF-β in the culture media. According to these results, 1,3-β-glucan exposure in vitro is suggested to promote the secretion of anti-inflammatory cytokines, which may lead to a decrease in the levels of Th1 cytokines and an increase in the levels of Th2 cytokines. 1,3-β-glucan is suggested to induce regulatory lymphocytes, which partly contributes to an increased secretion of anti-inflammatory cytokines in co-cultured mouse macrophages and lymphocytes in vitro.