title: Evaluation of cytotoxicity and immune modulatory activities of soyasaponin Ab: an in vitro and in vivo study.
abstract: To improve the immune efficacy of protein subunit vaccines, novel adjuvants are needed to elicit a suitable protective immune response and to promote long term immunologic memory. In this work, soyasaponin Ab, a major constituent among group A soyasaponins in soybeans was purified and prepared from soy hypocotyls. The immunomodulatory effects of soyasaponin Ab both in vitro and in vivo were investigated, and its pro-immunomodulatory molecular mechanism was also studied. For in vitro assays, with mouse macrophage cell line RAW264.7 as the studying model, both cytotoxicity and immune stimulatory activity were investigated to evaluate the potential of soyasaponin Ab as the vaccine adjuvant. The results indicated that soyasaponin Ab could be significantly safer than Quillaja saponins (QS). Soyasaponin Ab showed no toxicities over the tested concentration ranges compared to QS. Soyasaponin Ab was proved able to promote releases of inflammatory cytokines like TNFα and IL-1β in a dose-dependent manner. Furthermore, NF-κB signalling was also activated by soyasaponin Ab effectively. In addition, with TLR4 gene expression of RAW264.7 cell inhibited by RNA interference, immune stimulatory effects by soyasaponin Ab dropped down significantly. On the other hand, the in vivo experiment results showed that anti-ovalbumin (OVA) IgG, IgG1, IgG2a, IgG2b were significantly enhanced by the soyasaponin Ab and QS groups (p<0.05 or p<0.01). The results suggested that compared to QS, soyasaponin Ab may represent a viable candidate for effective vaccine adjuvant. TLR4 receptor dependent pathway may be involved in immune stimulatory effects of soyasaponin Ab.
authors.affiliation: Department of Animal Science, Shanghai Jiao Tong University, Shanghai 200240, China; Shanghai Municipal Veterinary Key Laboratory, 800 Dongchuan Road, Shanghai 200240, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Sun
authors.affiliation: Department of Food Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Xinbin
authors.initials: X
authors.lastname: Yan
authors.affiliation: Department of Food Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China.
authors.forename: Wenxiu
authors.initials: W
authors.lastname: Guo
authors.affiliation: Department of Food Science and Technology, Shanghai Jiao Tong University, Shanghai 200240, China; Bor S. Luh Food Safety Research Center, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: dyzhao@sjtu.edu.cn.
authors.forename: Dayun
authors.initials: D
authors.lastname: Zhao
mesh_terms: D000276:Adjuvants, Immunologic / Q000494:pharmacology*; D000818:Animals; D002460:Cell Line; D016207:Cytokines / Q000276:immunology; D005260:Female; D018546:Hypocotyl / Q000737:chemistry; D007074:Immunoglobulin G / Q000097:blood; D008264:Macrophages / Q000187:drug effects*; D051379:Mice; D008813:Mice, Inbred ICR; D015394:Molecular Structure; D016328:NF-kappa B / Q000378:metabolism; D012503:Saponins / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013025:Glycine max / Q000737:chemistry*; D051197:Toll-Like Receptor 4 / Q000378:metabolism
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D007074:Immunoglobulin G; D016328:NF-kappa B; D012503:Saponins; C493487:Tlr4 protein, mouse; D051197:Toll-Like Receptor 4; C551307:soyasaponin Ab
keywords: Adjuvant; Haemolysis; OVA; Soyasaponin Ab; TLR4