Lactobacillus plantarum Surface-Displayed ASFV (p14.5) Can Stimulate Immune Responses in Mice

African Swine Fever Virus (ASFV) has spread worldwide, and the lack of vaccines severely negatively impacts the pig industry. In this study, the p14.5 protein encoded by ASFV was used as the antigen, and the p14.5 gene was expressed in vitro using the Lactobacillus expression system. Three new functionally recombinant Lactobacillus plantarum (L. plantarum) were constructed and the expressions of the p14.5 protein, p14.5-IL-33-Mus fusion protein and CTA1-p14.5-D-D fusion protein were successfully detected using Western blot analysis. After oral immunization of SPF mice with recombinant L. plantarum, flow cytometry and ELISA were performed to detect the differentiation and maturity of T lymphocytes, B lymphocytes and DCs of the mice, which were higher than those of the control group. Specific antibodies were produced. The immunogenicity of the adjuvant group was stronger than that of the single antigen group, and the IL-33 adjuvant effect was stronger than that of the CTA1-DD adjuvant.