Type I feline coronavirus S protein and feline parvovirus VP2 protein bivalent recombinant protein effectively protection against FCoV and FPV challenge in cats

Feline coronavirus (FCoV) and feline parvovirus (FPV) are two highly pathogenic viruses that pose major threats to feline populations. In this research, we describe for the first time the development of a bivalent recombinant protein targeting the FCoV-I S and FPV VP2 antigens using the Bac-to-Bac baculovirus expression system. ELISA results demonstrated that the bivalent recombinant protein elicited robust, antigen-specific antibody responses against both FCoV S and FPV VP2 proteins in mice. Flow cytometry further revealed significantly elevated IFN-γ secretion in splenocytes from immunized mice, indicating a strong cellular immune response. In challenge experiments, the bivalent protein conferred complete protection against both FCoV and FPV. These results demonstrate that the bivalent recombinant protein provides strong humoral and cellular immune protection and effectively prevents FCoV-I and FPV infection. This candidate vaccine shows considerable potential for further development in feline disease prevention.