Mice exposed to Porphyromonas gingivalis prior to immunization with collagen II and incomplete Freund’s adjuvant generates increased splenic T-helper type 17-related responses. Murine splenocytes were isolated from mice that received 15 oral gavages of P. gingivalis (Pg) followed by incomplete Freund’s adjuvant (IFA)/collagen II (CII) immunization at day D30 according to Methods. Splenocytes were collected at D44 and D73 and reactivated in vitro with CII. Supernatants collected and evaluated for protein expression at D44 demonstrated increased (A) T-helper type (Th)1-related response via interleukin (IL)-12p70, (B) increased Th2-related response via IL-5, and (C) increased Th17-related responses via IL-1β, tumor necrosis factor (TNF)-α, transforming growth factor beta (TGF-β), and IL-23 if mice had P. gingivalis infection in mice immunized with IFA/CII. (D) At D73, immunized mice demonstrated increased expression of TNFα and TGF-β, with IL-6 being significantly upregulated independent of in vitro reactivation. Error bars represent ± standard error of the mean of eight mice per group, P <0.05, analysis of variance followed by Tukey’s multiple comparison test, and Student’s t test.