Immunoadjuvant Effect of Ginsenoside F4

Abstract

There have been many attempts to treat candidal infections by immunological approaches. One attempt is to find a certain adjuvant that induces a protective antibody in host. Previously, we have reported that MAb B6.1, specific for β-1,2 mannotriose located on the Candida albicans cell wall (CACW), protects mice against disseminated candidiasis and vaginal infection. However, the isolation of such an epitope is very costly and requires tremendous amount of time. Thus, this led us to find a simple way to obtain a compound that induces protective antibody. For this purpose, we focused on the discovery of immuoadjuvants capable of inducing protective antibodies. In the present study, we tested whether ginsenoside F4 from Red Ginseng has immunoadjuvant activity against fungal infection. Data displayed that a formulae of CACW combined with F4 (CACW/F4) enhanced production of anti-C. albicans antibody in mice. Analyses by IgG isotyping showed that the formulae suppressed IgG1 (Th2-immunity polarized) but enhanced IgG2b (Th1-immunity polarized), thus resulting in a Th1 immune response. This effect was assessed in a murine model of disseminated candidiasis due to C. albicans. The assesment displayed that the formulae enhanced resistance of mice against the candidiasis, whereas CACW alone was not protective. Overall, F4 has immunoadjuvant activity that provokes the induction of protective antibody in mice through a possible mechanism that enhances Th1 immunity in mice.