Immunoenhancement Effects of Glycosaminoglycan from Apostichopus japonicus: In Vitro and In Cyclophosphamide-Induced Immunosuppressed Mice Studies

In this study, the immunomodulatory activities of Apostichopus japonicus glycosaminoglycan (AHG) on the nature killer (NK) cells, cytotoxic T lymphocytes (CTLs) and cyclophosphamide (CY)-treated mice were investigated. After stimulation with multiple concentrations of AHG (0–100 μg/mL), NK cells and CTLs displayed outperformance against YAC-1 and B16 cells, respectively. Furthermore, the mitogen-induced splenic lymphocyte proliferation in CY-induced immunosuppressed mice was significantly promoted by AHG. In addition, the administration of AHG dramatically increased the splenocytes Ca(2+) concentration and the delayed-type hypersensitivity (DTH) reaction in a dose-dependent manner. Besides, AHG could strongly increase the total antioxidant capacity (T-AOC), the activities of superoxidase dismutase (SOD), catalase (CAT) as well as glutathione peroxidase (GSH-PX), and could decrease the malondialdehyde (MDA) level in the heart, kidney and liver. These findings indicated that AHG played an important role in the immune enhancement and protection against CY-induced immunosuppression and oxidative damage. Our findings provide experimental evidence for further research and possible immunostimulatory applications of AHG in clinical practice.