Improving adjuvanticity of crude polysaccharides from cultivated Artemisia rupestris L. for influenza vaccine by promoting long-term immunity and T1/T2 response with dose-sparing effect.

ETHNOPHARMACOLOGICAL RELEVANCE

Influenza virus vaccines (IVV) with balanced T1/T2 responses are critical for controlling seasonal influenza. Emerging evidences suggest that herbal polysaccharides can induce potent T1 or mixed T1/T2 responses.

AIM OF STUDY

The study aims to determine the efficacy and safety of crude polysaccharides from cultivated Artemisia rupestris L. (CPCAR) as an adjuvant for IVV.

MATERIALS AND METHODS

CPCAR was prepared with hot extraction and ethanol precipitation method and primary physico-chemical characters were tested. Mice were vaccinated by subcutaneous route with IVV formulated with different dose of CPCAR to detecting the elicited T1/T2 responses and long-term immune responses with dose-sparing sparing effect.

RESULTS

IVV formulated with CPCAR without LPS contamination could augment balanced T1/T2 responses, as indicated by early IgG response, hemagglutination inhibition (HAI) antibodies, effector T-cells, and cytotoxic T lymphocytes (CTL). Moreover, CPCAR elicited long-term IgG, HAI antibodies, memory T cells, and balanced CD4/CD8 responses within 168 days after vaccination. Compared with IVV alone, a low or high dose of IVV formulated with CPCAR improved the levels of IgG, IgG1, and IgG2a and enhanced memory T cells and balanced CD4/CD8 responses, displaying a 10-fold dose-sparing effect. As determined by IgE response and monitoring results of weekly body weight and daily symptoms after vaccination, anaphylaxis or adverse effect was not observed.

CONCLUSIONS

Collectively, the study demonstrated the potential of CPCAR as an aqueous polysaccharide adjuvant for IVV to induce rapid and balanced T1/T2 responses and long-lasting immunity with dose-sparing effect.