Immunological adjuvant effect of Japanese ginseng saponins (JGS) on specific antibody and cellular response to ovalbumin and its haemolytic activities

In this study, the saponins (JGS) extracted from the rhizoma of Japanese ginseng were evaluated for their haemolytic activities and their potential ability as adjuvants on the immune responses to ovalbumin (OVA) in mice. The haemolytic activity of JGS was determined using 0.5% rabbit red blood cell, with its HD50 value being 177.78 ± 6.77 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 JGS (50, 100 or 200 μg) on Days 1 and 15. Two weeks later (Day 28), concanavalin A (ConA)-, lipopolysaccharide (LPS)-, OVA-stimulated splenocyte proliferation and OVA-specific antibodies in serum were measured. JGS significantly enhanced the ConA-, LPS-, and OVA-induced splenocyte proliferation in the OVA-immunized mice especially at a dose of 100 μg (P < 0.05 or P < 0.01). The OVA-specific IgG, IgG1 and IgG2b antibody levels in serum were also significantly enhanced by JGS compared with OVA control group (P < 0.01). The results suggest that JGS showed a slight haemolytic effect and enhanced significantly a specific antibody and cellular response against OVA in mice.