Alhagi honey polysaccharides encapsulated into PLGA nanoparticle-based pickering emulsion as a novel adjuvant to induce strong and long-lasting immune responses.

Alhagi honey polysaccharides, extracted from a perennial plant Alhagi pseudalhagi syn, possessed many biological activities such as immune enhancement, anti-tumor effect, and antioxygenation. In this study, we used Alhagi honey polysaccharide encapsulated (poly lactic-co-glycolic acid) (PLGA) nanoparticles to prepare an assembled particles-oil pickering emulsion: PPAS and PEI-PPAS. We investigated the characterization of two pickering emulsions, and the possible mechanism to enhance immune responses. The results showed that PPAS and PEI-PPAS both could load high adsorption of OVA and had ability to sustained controlled release OVA. In vivo experiment, PEI-PPAS/OVA enhanced the levels of IgG and cytokines. Meanwhile, it could effectively target dendritic cells (DCs), promoted the cellular uptake of OVA then activated DCs in lymph nodes. And this effect of PEI-PPAS might be induced through the MHC II and MHC I pathway in DCs. Thus, these findings demonstrated that PEI-PPAS could induce a strong and long-term cellular and humoral immune response, and have potential to applied to vaccine adjuvant delivery system.

Evaluation of optimum conditions for Achyranthes bidentata polysaccharides encapsulated in cubosomes and immunological activity in vitro.

Cubosomes, as biocompatible carriers in drug delivery systems, consist of curved bicontinuous lipid bilayers. With a honeycombed structure divided into two internal aqueous channels, cubosomes could be used for many bioactive ingredients. Achyranthes bidentata polysaccharides (ABPs) are isolated from the roots of Achyranthes bidentata, used in Chinese herbal medicine, and present a noticeable effect as an immunomodulator. This study investigates the optimal preparation of combined cubosome-ABP (Cub-ABP) nanoparticles using response surface methodology and explores their characteristics and stability. The encapsulation efficiency of optimized Cub-ABPs was 72.59%. In-vitro stability studies demonstrated the stability of Cub-ABPs and cubosome nanoparticles without ABPs; both were stable for up to 25days. Safe concentrations of Cub-ABPs and cubosome nanoparticles without ABPs are 104.06µg/mL and 208.13µg/mL with comparatively low cytotoxicity against lymphocytes. Moreover, the feasible immunomodulatory effects of Cub-ABPs were determined by evaluating their proliferation and change of CD4+/CD8+ ratio on splenic lymphocytes in vitro. Proliferation and flow cytometry studies revealed that, compared with free ABPs and blank cubosomes, Cub-ABPs proved more effective in promoting lymphocyte proliferation and in triggering the transformation of T-lymphocytes into Th-cells.