Immunoregulatory properties of the cultivated Artemisia rupestris L. polysaccharide as a potential adjuvant

Two components (CARP-1 and CARP-2) were fractionated from cultivated Artemisia rupestris L. and then characterized by HPGPC and HPLC. CARP-1 with a molecular weight of 2.72 × 104 Da and CARP-2 with a molecular weight of 2.08 × 104 Da were mainly composed of galactose, arabinose, glucose and rhamnose. Polysaccharides were the active components as confirmed by the increased CD40, CD86, TNF-α, and IL-6, allogeneic T-cell activation, and reduced endocytosis in vitro assays. CARP-1 and CARP-2 at 10 to 3200 μg/mL was not cytotoxic to the splenocytes of mice. After immunization, CARP-1 and CARP-2 combined with OVA elicited mixed Th1/Th2 responses, especially polarized Th1 response. Furthermore, TLR4 inhibitor decreased CARP-1- and CARP-2-induced DC activation. Western blot revealed that CARP-1 and CARP-2 stimulated the phosphorylation changes of target proteins in NF-κB and MAPK pathways in a dose- or time-related manner. Overall, CARP-1 and CARP-2 could be exploited as an effective and safe adjuvant for vaccines.