Cationic Chinese yam polysaccharides nanoparticles-based Pickering emulsion for delivery vaccine and adjuvant to enhance immune response.

Chinese Yam polysaccharides (CYP) are promising vaccine adjuvant. For the co-delivery of adjuvant and vaccine, the cationic Chinese yam polysaccharides nanoparticles-based Pickering emulsion delivery system (PEI-CYP-PPAS) was developed. Here, we assembled PEI-CYP-PPAS with Ovalbumin (OVA) antigen and explored its potential mechanisms to improve immune responses. According to the results, PEI-CYP-PPAS promoted uptake, activation, and antigen cross-presentation of dendritic cells (DCs) in vitro. Following vaccination, it prolonged antigen retention at the injection site, recruited immune cells, and promoted the antigen migration to the lymph nodes. It also enhanced the antigen uptake by DCs and the activation of DCs, T cells, and germinal centers within draining lymph nodes. Furthermore, the PEI-CYP-PPAS promoted T lymphocytes differentiation, activated CD8+ cytotoxic T lymphocytes, and improved immunological memory. It increased the production of OVA-specific antibodies and cytokines in serum to enhance both humoral and cellular immune responses. Collectively, the PEI-CYP-PPAS cationic Pickering emulsion delivery system represents a potent delivery platform and provides guidance for the development of effective and novel vaccine adjuvants.