Adjuvant activity of Chinese herbal polysaccharides in inactivated veterinary rabies vaccines

Four botanical polysaccharide preparations (from Astragalus, Echinacea, wolfberry, and kelp) were evaluated as immunopotentiators/adjuvants of a veterinary rabies vaccine. Results showed that lymphocyte proliferation and some cytokines were significantly elevated, with cellular immune responses skewed towards Th1 and Tc1. All four polysaccharides produced accelerated and enhanced effects on rabies-neutralizing antibody responses in mice and dogs. The results also indicated that certain botanical polysaccharides could be used in rabies vaccine formulations for early and persistent prophylaxis.