Immunoadjuvant Effect of Platycodin D from Platycodon grandiflorum

Abstract

In vaccine development, the major points may be induction of effective and increased levels of antibody pro- duction. This is especially the case when the antigenic sources are carbohydrates. For many years, thus, we have researched various types of formulations such as liposomal and conjugate vaccines. However, the fastidious formulation process and high costs are a problem. For this reason, there is currently a focus on utilizing immunoadjuvants. In this present study, we tested if platycodin D (PLD) from Platycodon Radix have immunoadjuvant activity against the cell wall of Candida albicans (CACW). The resulting data showed that in the murine model of antibody production, CACW combined with PLD (CACW/ PLD/IFA) increased the production of antibodies specific to C. albicans when compared to the antibody production by (CACW/IFA)-induction, which was used as a negative control (P<0.05). In the case of (CACW/PLD/IFA), the antibody pro- duction was 1.4 times as that of the CFA. In addition, formulations containing either had a prolonged antibody inducing activ- ity maintaining the initial titers of antibody as compared to the CFA formula. Cytokine profiling with the antisera displayed that the PLD produced both Th1 and Th2 immunoresponses, but Th1 dominant was much greater (P<0.05). Furthermore, (CACW/PLD/IFA) formula enhanced resistance of mice against disseminated candidiasis, whereas the CFA had no such effect. In conclusion, PLD has an immunologic activity, which is protective against the disease. Thus, PLD can be a goof candidate for a new immunoadjuvant in development of the fungal vaccine.