A novel sarsasapogenin glycoside from Asparagus racemosus elicits protective immune responses against HBsAg

The aim of the present investigation was to evaluate the adjuvant potential of a novel sarsasapogenin glycoside (immunoside) isolated from Asparagus racemosus in combination with hepatitis B surface antigen (HBsAg). Various in vitro and animal derived protocols were used to determine the response of immunoside adjuvanted with HBsAg and the results were compared with alum adjuvanted with HBsAg. Several biomarkers such as antibody titre (IgG, IgG1/IgG2a) were measured in mice sera. Cell proliferation, cytokines (IL-2, IFN-γ and IL-4), and lymphocyte sub-populations (CD4/CD8, CD3 and CD19) were determined in splenocytes from mice administered subcutaneously with test substances. In these cells CD4/CD8 derived IFN-γ release was also determined. Macrophage preparations were used for the determination of IL-12, IFN-γ and nitrite content. Seroconversion potential was compared with a standard vaccine. Acute safety evaluation of immunoside was done in mice. Effect of immunoside on red blood cell haemolysis was determined. The results have suggested that immunoside potentially enhanced anti-HBsAg immune response via augmenting Th1/Th2 response in a dose dependent manner.