Immunological Adjuvant Effect of a Water‐Soluble Polysaccharide, CPP, from the Roots of Codonopsis pilosula on the Immune Responses to Ovalbumin in Mice

Abstract

In this study, one water-soluble polysaccharide, CPP, was purified from the root of Codonopsis pilosula. The immunomodulatory effect and the adjuvant potential of CPP on the cellular and humoral immune response of ICR mice against ovalbumin (OVA) were investigated. CPP was shown not to be lethal in vivo for mice in doses ranging from 0.5 to 4 mg. ICR Mice were immunized subcutaneously with 0.1 mg of OVA alone or with 0.1 mg of OVA dissolved in saline-containing aluminum hydroxide gel (Alum) (0.2 mg), QuilA (0.01 and 0.02 mg) or CPP (0.5, 1 or 2 mg) on days 1 and 15. Two weeks later (day 28), concanavalin A (ConA)-, lipopolysaccharide (LPS)-, and OVA-stimulated splenocyte proliferation, and OVA-specific serum antibodies were measured. CPP significantly enhanced the ConA-, LPS-, or OVA-induced splenocyte proliferation in the OVA-immunized mice especially at a dose of 1 mg (P<0.05 or P<0.01). The OVA-specific IgG, IgG1, and IgG2b antibody levels in serum were also significantly enhanced by CPP compared with OVA control group (P<0.05 or P<0.01). The results suggest that CPP could be a safe efficacious adjuvant for use in vaccines against both pathogens and cancer.