Preparation and mechanism study of Alhagi honey polysaccharide-aluminum Pickering emulsion adjuvant for improving intestinal mucosal immune function

Introduction Bovine viral diarrhea virus (BVDV) can induce diarrhea and mucosal tissue damage, and in severe cases, may result in fatal. Targeted adjuvants capable of enhancing intestinal IgA antibody responses represent an effective strategy for preventing bovine viral diarrhea. Methods In this study, an Alhagi honey polysaccharide Pickering emulsion (AHPPE) adjuvant was developed by incorporating Alhagi honey polysaccharide (AHP) and retinoic acid (RA) with an aluminium-based adjuvant. Mice were subsequently immunized via intramuscular injection to evaluate the adjuvants' immunostimulatory potential. Results The results demonstrate that the particle size of AHPPE is 2133 nm, with excellent dispersion and stability. The encapsulation efficiencies for BVDV and AHP were 66.8% and 73.2%, respectively. AHPPE demonstrated recruitment of antigen-presenting cells at the injection site and activated IgA cells in the duodenum, jejunum, and ileum, inducing to increased IgA expression across multiple intestinal segments. Furthermore, AHPPE significantly induced serum IgG production and elevated levels of cytokines, including IL-4, IL-10, IL-17, IFN-γ, and TNF-α ( P