Construction of a sIgA-enhancing anti-Porphyromonas gingivalis FimA vaccine and nasal immunization in mice.

Porphyromonas gingivalis is implicated in the etiology of chronic periodontitis. Fimbriae are one of several critical surface virulence factors of P. gingivalis. Interleukin 15 (IL-15) is a critical important cytokine for the differentiation of B-1 cells into IgA-inducing cells in mucosal tissues and the proliferation of B cells. The present study constructed a co-expression plasmid pIRES-fimA:IL-15 encoding fimbrinllin (FimA), a subunit of fimbriae and IL-15 as a sIgA-enhancing anti-P. gingivalis FimA vaccine. The plasmid pIRES-fimA:IL-15 was transfected to CHO cells. The expressions of FimA and IL-15 in CHO cells were verified by Western blot and ELISA. Mice were immunized with pIRES-fimA:IL-15 via nasal or intramucusal route. The results showed that nasal immunization was capable of promoting Ag-specific immune responses in the oral region as well as systemic immunity. When immunized via nasal route, IL-15 expressed by the plasmid enhanced FimA-specific sIgA antibody response. In conclusion, a co-expression plasmid pIRES-fimA:IL-15 has been constructed, and when immunized via nasal route, antigen-specific sIgA antibody response could be modulated positively in immunized mice.