Immune-enhancing effect of fermented soybean food, Cheonggukjang on cyclophosphamide-treated immunosuppressed rat

Cheonggukjang (<i>CGJ</i>) is a traditional food, made by the fermentation of beans, and it has different recipes for different regions in Korea. However, it has anti-inflammatory, anti-cancer, and anti-obesity effects, and is known to affect changes in the intestinal microbiota. In this study, we investigated the immune-enhancing effects of four type <i>CGJ</i>s (one commercial and three transitional <i>CGJ</i>s). In the cyclophosphamide (CP)-treated immunosuppressed rat, oral administration of <i>CGJ</i>s for 4 weeks was used to investigate weight of body and immune organ, change of microbiota, blood and serum parameters, inflammation pathways (MAPKs and NFκB) and histology of spleen. It showed an immunity-enhancing effect through increase Bacteroidetes in gut, the recovery of complete blood count, levels of cytokines and IgG, activation of inflammatory pathways, and histology of spleen. In conclusion, these results show that the intake of a commercial brand CGJ, and traditional CGJs can maintain or promote the body's immunity.