Abstract
Porphyromonus gingivalis is a major pathogen of chronic periodontitis. An outer membrane protein with a molecular mass of 40-kDa (40k-OMP) is a highly immunogenic surface protein produced by P. gingivalis. In this study, to develop an effective vaccine against P. gingivalis infection, we assessed T helper (Th) cell responses in systemic and mucosal compartments after 40k-OMP was administered transcutaneously. When CD4+ T cells isolated from the spleens of mice immunized with 40k-OMP alone or 40k-OMP plus cholera toxin were restimulated with 40k-OMP in vitro, significant levels of proliferative responses were induced. In contrast, only low levels of CD4+ T cell proliferation were induced in cervical lymph nodes. Analysis of Th1 [interferon (IFN)-γ] and Th2 [interleukin (IL)-4, IL-5, and IL-6] cytokine responses showed that 40k-OMP-specific Th cells from the spleen produced significant levels of IL-4, IL-5, and IL-6 but did not trigger changes in IFN-γ production. These results suggest that transcutaneous administration of 40k-OMP can elicit 40k-OMP-specific Th2-type cytokine responses in systemic, but not mucosal, lymphoid tissues.
