Cheonggukjang polysaccharides enhance immune activities and prevent cyclophosphamide-induced immunosuppression

Cheonggukjang is a traditional Korean fermentation product prepared from soybean that is reported to have various biological functions. We previously reported that the polysaccharides from Cheonggukjang (PSCJ) have immunostimulatory activities in RAW 264.7 macrophages and primary cultured splenocytes. In this study, the immunostimulatory activities of the PSCJ were investigated further using various experimental models such as in vitro, ex vivo, and in vivo. The PSCJ was able to stimulate the complement system (ITCH50: 30.6%). In primary cultured mouse peritoneal macrophages, the PSCJ was found to significantly increase nitric oxide and immunostimulatory cytokines (IL-6 and IL-12) production in a concentration-dependent manner (1-100 μg/mL). In the normal mice model, the oral administration of the PSCJ increased the weight of spleen (p < 0.05 at 100 and 200 mg/kg) and improved the phagocytic rates of peritoneal macrophages (p < 0.05 at 200 mg/kg) and lymphocytes proliferation (p < 0.05 at 100 and 200 mg/kg). Similarly, the PSCJ markedly restored the decreased lymphocytes proliferation (p < 0.01 at 200 mg/kg), natural killer cell activity (p < 0.01 at 200 mg/kg), and white blood cell count (p < 0.01 at 100 and 200 mg/kg) in the cyclophosphamide-induced immunosuppressed mice model. These results suggest that the PSCJ could be utilized as an effective immunostimulatory agent.