Adjuvant effect of Achyranthes bidentata saponins on specific antibody and cellular response to ovalbumin in mice

In this study, the haemolytic activities of Achyranthes bidentata saponins (ABS) and its adjuvant potentials on the cellular and humoral immune responses of ICR mice against ovalbumin (OVA) were evaluated. We determined the haemolytic activity of ABS using 0.5% rabbit red blood cell. The concentration inducing 50% of the maximum haemolysis (HD50) for ABS was 164.59 ± 13.41 μg/ml. ICR mice were immunized subcutaneously with OVA 100 μg alone or with OVA 100 μg dissolved in saline containing Alum (200 μg), QuilA (10 and 20 μg) or ABS (50, 100 or 200 μg) on Days 1 and 15. Two weeks later (Day 28), concanavalin A (Con A)-, lipopolysaccharide (LPS)- and OVA-stimulated splenocyte proliferation and OVA-specific antibodies in serum were measured. ABS significantly enhanced the Con A-, LPS-, and OVA-induced splenocyte proliferation in the OVA-immunized mice especially at a dose of 100 μg (P < 0.05 or P < 0.025). OVA-specific serum IgG, IgG1 and IgG2b antibody titers were also significantly enhanced by ABS compared with OVA control group (P < 0.05 or P < 0.025). The results suggest that ABS showed a slight haemolytic effect and enhanced significantly a specific antibody and cellular response against OVA in mice.