Porphyromonas gingivalisB cell Antigen Epitope Vaccine, pIRES-ragB'-mGITRL, Promoted RagB-Specific Antibody Production and Tfh Cells Expansion

The outer membrane protein RagB is one of the major virulence factors of Porphyromonas gingivalis (P. gingivalis). To prevent periodontitis and associated systemic diseases induced by P. gingivalis, we built B cell antigen epitope vaccine characterized by pIRES-ragB'-mGITRL to induce a protective immune responses. The B cell antigen epitope and scrambled peptide of ragB were predicted, cloned into pIRES and constructed pIRES-ragB', pIRES-scrambled epitopes and pIRES-ragB'-mGITRL. pIRES-ragB'-mGITRL was transfected into COS-7 cells. Subsequently, the 6-week-old female BALB/c mice were challenged by P. gingivalis following three time immunization by pIRES, pIRES-ragB', pIRES-scrambled epitopes and pIRES-ragB'-mGITRL. The levels of RagB-specific antibody in the serum and Tfh cells in the spleen were measured by ELISA and flow cytometry, respectively. And higher levels of RagB-specific IgG were produced in the immunized mice with pIRES-ragB'-mGITRL. Additionally, the number of Tfh cells was also expanded and lesions were diminished in pIRES-ragB'-mGITRL mice comparing with control groups. Our results clearly demonstrated that P. gingivalis B cell antigen epitope vaccine, pIRES-ragB'-mGITRL, could induce protective immune responses. Furthermore, our data also indicated that pIRES-ragB'-mGITRL was a potential therapeutic vaccine against P. gingivalis.