Preparation of polyacrylate/nanoemulsion composites and their adjuvant activity with OVA as the model antigen

• Polyacrylate/nanoemulsion composites were prepared and particle sizes were tested. • Adsorption properties of polymer composites on OVA were tested by ELISA method. • The polyacrylate/nanoemulsion composites’ adjuvant activity was tested in BALB/c mice. • OVA-specific IgG, IgG1, and IgG2a antibody titers showed the best formula. • Study confirmed synergistic adjuvant effect of polyacrylate, nanoemulsion on OVA. A series of polyacrylate/nanoemulsion composites were prepared to form a new kind of nanoemulsion, their particle sizes and polydispersity indices were measured. The particle sizes of the polyacrylate/nanoemulsion composites are consistent with nanoemulsions used in the system. In addition, an ELISA-specific antigen-antibody binding method was used for physical adsorption experiments on ovalbumin. Results showed that the adsorption performance of the polyacrylate/nanoemulsion system is best when the particle size was 55 nm, and the nanoemulsion content was 20 wt%, 30 wt%, or 40 wt%. Meanwhile, in order to select the optimum experimental conditions, in vivo immunity experiments in mice were carried out to analyze the adjuvant properties of ovalbumin as a model antigen. Analysis of ovalbumin-specific IgG, IgG1, and IgG2a antibody titers showed the best results when the particle size of the polyacrylate/nanoemulsion composites is 55 nm, the polyacrylate content is 0.5 wt%, and the nanoemulsion contents is 20 wt%. Meanwhile, titer analysis also showed that the polyacrylate obviously enhanced the IgG2a titer in mice. Our polyacrylate/nanoemulsion composites can both stimulate humoral and cellular immunity and have an enhanced adjuvant effect on water-soluble protein antigens.