Dual-mode delivery of canine parvovirus type 2c VP2 protein in recombinant Lactobacillus plantarum: Surface display and intracellular expression systems.

Canine parvovirus type 2 (CPV-2) causes an acute and highly transmissible disease characterized by severe hemorrhagic enteritis and myocarditis, ultimately resulting in the death of dogs and wild carnivores. At present, although vaccines have been developed for CPV-2, there are no specific and effective vaccines available for prevention of CPV-2c infection. To develop mucosal vaccines against CPV-2c, we constructed recombinant Lactobacillus plantarum (L. plantarum) expressing the VP2 antigen of CPV-2c. We amplified the VP2 gene from a CPV-2c subtype strain and subsequently constructed recombinant L. plantarum NC8 strains that express the VP2 and pgsA'-VP2 proteins, respectively. This work has shown that recombinant L. plantarum strains NC8/pSIP409-VP2 and NC8/pSIP409-pgsA'-VP2 can effectively activate dendritic cells maturation markers (CD80, CD86, and MHC-Ⅱ) while inducing robust IgG and IFN-γ responses in both mice and dogs. Furthermore, recombinant L. plantarum elevated sIgA and IgG concentrations and augmented B220⁺IgA⁺ cell populations. The data indicated that the recombinant L. plantarum developed in this work can significantly enhance the host immunity as an oral vaccination and may contribute to the prevention and control of canine parvovirus infection in dogs.