Construction and Immunogenicity Detection of Canine Parvovirus-like Particles Fusion with Canine Febrile Antigen Epitopes

This study aimed to design and evaluate the immunogenicity of a dual-valent virus-like particles (VLP) vaccine that can simultaneously target Canine distemper virus (CDV) and Ca nine parvovirus virus (CPV).By bioinformatic analysis, conserved antigen epitopes of the three major functional proteins of CDV were screened and inserted into CPV-VP2 proteins by two different methods to construct recombinant expression plasmids CDPV1 versus CDPV2.Thr ee-dimensional structure, hydrophobicity and stability predictions of the two recombinant proteins showed that their hydrophobicity were 0.233 and 0.251, and their structural stability scores were 0.77 and 0.78, respectively.Recombinant plasmids were co-transformed with molecular chaperone pTf16 to be expressed in E. coli BL21(DE3), respectively, and the optimal expression conditions were determined after optimization: 0.25 mmol/L IPTG, 2 g/L L-arabinose in duction, and culture at 25{degrees}C for 16 h.Purified recombinant proteins can self-assemble in vitro to form VLPs about 23.5 nm in diameter with a hemagglutination titer of 1:29.The mouse immune test showed that the hemagglutination inhibition titer peaked on the 7th day after the third immunization, and the neutralizing Antibody level could reach up to 1:28.The CPV VLP s constructed in this institute carrying CDV antigen epitopes were able to successfully assemble in vitro and were well immunogenic, providing experimental basis for the development of a canine polyvalent vaccine.