Immunogenicity of recombinant outer membrane porin protein and protective efficacy against lethal challenge with Bordetella bronchiseptica in rabbits

Aims The outer membrane porin protein (OMPP) of Bordetella bronchiseptica is an important adhesion factor and protective immunogen. The aim of this study was to verify the immunogenicity of recombinant OMPP and its protective efficacy against a lethal challenge with B. bronchiseptica in rabbits. Methods and Results Soluble rOMPP was successfully expressed in Escherichia coli, and the purified recombinant protein was mixed with the ISA 201 VG adjuvant to prepare a subunit vaccine for B. bronchiseptica. Rabbits were immunized with the rOMPP subunit vaccine and then infected with the virulent B. bronchiseptica strain QDBb01. Rabbits immunized with the subunit vaccine were completely protected compared to the control group, and the protective effect was obviously better than that of the inactivated whole-cell vaccine. Moreover, analysis of the immunization duration showed that the rOMPP subunit vaccine provided immune protection for at least 4 months after the second immunization. Conclusions The rOMPP subunit vaccine completely protected rabbits from a subsequent B. bronchiseptica challenge. Significance and Impact of the Study The results will provide key information for the development of a safe and effective recombinant subunit vaccine against B. bronchiseptica in rabbits.