Ginseng stem-leaf saponins (GSLS) and mineral oil act synergistically to enhance the immune responses to vaccination against foot-and-mouth disease in mice

Paclitaxel acts as an adjuvant to promote both Th1 and Th2 immune responses induced by ovalbumin in mice

Paclitaxel, a diterpenoid isolated from the bark of the Taxus cuspidate cv. Nana, was evaluated for its adjuvant effect on the immune responses in a mouse model. Fifty-six mice were randomly distributed into seven groups with 8 mice in each. Animals were subcutaneously immunized on days 1 and 21 with 100microg of paclitaxel, 10microg of ovalbumin (OVA), OVA with paclitaxel (50, 100 or 200microg) or with aluminum hydroxide (alum). Two weeks after the primary and boost immunizations, blood samples were collected for measurement of serum antibodies. Splenocytes were separated for detection of lymphocyte proliferation in responses to concanavalin A (Con A), lipopolysaccharide (LPS) and OVA, and mRNA expression of Th1 cytokines (IFN-gamma and IL-12), Th2 cytokines (IL-10 and IL-5) and transcription factors T-bet/GATA-3 (Th1/Th2 switcher). Results showed that coadministration of OVA with paclitaxel induced significantly higher IgG, IgG1, IgG2a, IgG2b, IgG3 and IgM responses than when OVA was used alone. In addition, up-regulated T-bet/GATA-3 together with significantly increased mRNA expression of IL-4, IL-10, IFN-gamma and IL-12 by splenocytes, as well as the proliferative responses of splenocytes to Con A, LPS and OVA were observed in paclitaxel-adjuvanted groups. Incubation of a murine macrophage-like cell line with paclitaxel significantly increased TNF-alpha and -10 released from the cells and expression of microRNAs such as miR-155, miR-147, miR-146a and miR-132. Therefore, paclitaxel activated both Th1 and Th2 responses. Considering its unique adjuvant effect demonstrated in this study and a safe record clinically used as an antineoplastic agent, paclitaxel could be an ideal adjuvant candidate when mixed Th1/Th2 immune responses are needed.

Enhancement of immune responses to influenza vaccine (H3N2) by ginsenoside Re

This study was designed to evaluate the adjuvant effect of ginsenoside Re isolated from the root of Panax ginseng on the immune responses elicited by split inactivated H3N2 influenza virus antigen in a mouse model. Forty-eight ICR mice were randomly distributed into six groups with 8 mice in each group. All animals were subcutaneously (s.c.) immunized twice on weeks 0 and 3 with 50 microg Re, inactivated H3N2 influenza virus antigen equivalent to 10 or 100 ng of hemogglutinin (HA) or inactivated H3N2 influenza virus antigen equivalent to 10 ng HA adjuvanted with Re (25, 50 or 100 microg). Two weeks after the boost, blood samples were collected for measurement of serum IgG, the IgG isotypes and HI titers. Splenocytes were separated for the detection of lymphocyte proliferation and production of IFN-gamma and IL-5 in vitro. Results showed that co-administration of Re significantly enhanced serum specific IgG, IgG1, IgG2a and IgG2b responses, HI titers, lymphocyte proliferation responses as well as IFN-gamma and IL-5 secretions, indicating that both Th1 and Th2 were activated. Considering the adjuvant effect demonstrated in this study, Re deserve further studies for improving the quality of vaccines where mixed Th1/Th2 immune responses are needed.

Adjuvant activities of saponins from traditional Chinese medicinal herbs

New generation vaccines such as recombinant, antigen purified and DNA vaccines are poorly immunogenic due to the lack of an innate immune stimulus. Therefore, search of new adjuvants for these vaccines has become a topic of interesting. In new adjuvant development, saponins are outstanding candidates. Recently, increased attention has been received on plant-derived saponins in search of new adjuvant candidates from traditional Chinese medicinal herbs such as Panax ginseng, Astragalus species, Panax notoginseng,Cochinchina momordica, Glycyrrhiza uralensis and Achyranthes bidentata. Many of the saponins have been found to have adjuvant effects on purified protein antigens. The chemical structures of the saponins are related to their adjuvant activities, and influence the nature of the immune responses. Saponin adjuvants have been reported to stimulate secretion of a broad range of cytokines, suggesting that saponins may act by triggering innate immunity. As these plant-originated adjuvants may promote different branches of the immune system, they have the potential to be used in design of new vaccines so as to induce a desired immune response.