Construction of an Oral Vaccine Based on Multiple Antigens of African Swine Fever Virus Displayed on the Surface of Bacillus Subtilis Spores and Study of its Immune Effect in Rats.

In this study, we constructed an oral vaccine by expressing fusion antigens of African swine fever virus (ASFV) on the surface of Bacillus subtilis spores and explored its immunogenicity. Fusion proteins were designed, and recombinant strains that could stably express target proteins on the spore surface were successfully constructed. After oral immunization of rats, the spleen index and the levels of ASFV-specific IgG, interleukin-2, and interferon-γ were markedly increased, indicating effective activation of humoral and cellular immunity. This study established a reliable spore surface display system. The recombinant spores triggered favorable immune responses in vivo, providing an experimental foundation for the development of novel ASFV oral vaccines.