Recombinant Lactobacillus casei Expressing Capsid Protein VP60 can Serve as Vaccine Against Rabbit Hemorrhagic Disease Virus in Rabbits

Wang, Li; Xia, Tian; Guo, Tiantian; Ru, Yi; Jiang, Yanping; Cui, Wen; Zhou, Han; Qiao, Xinyuan; Tang, Lijie; Xu, Yigang; Li, Yijing

In this study, the protective efficacy of L. casei was analyzed using rabbits. Our results show that survival rates of rabbits vaccinated with recombinant L. casei and inactivated virus vaccine were at 100% after the viral challenge; however, none of the rabbits in the PBS-treated group survived challenge with RHDV. This finding indicates that pPG-eGFP-VP60/LC393, administered via oral immunization, effectively induced a sufficient immune response to protect rabbits against infection with RHDV. Rabbits infected with RDHV often develop acute necrotizing hepatitis and disseminated intravascular coagulation in the liver, spleen, kidney, and other solid organs [1] . Histopathological analysis showed topical histopathological changes in RDH of the liver and spleen of the PBS-treated group after challenge with RHDV. However, these changes were not observed in the organs of rabbits immunized with recombinant L. casei pPG-eGFP-VP60/LC393 or inactivated virus vaccine. The villi of the small intestine were necrotic and severely desquamated in the PBS-treated group and the group treated with inactivated virus vaccine. The group administered L. casei pPG-eGFP-VP60/LC393 showed the intact structure of the villi in the small intestine. This finding indicates that L. casei protected the intestinal environment against the effects of RHDV.