Mice exposed to Porphyromonas gingivalis prior to immunization with collagen II and complete Freund’s adjuvant exhibit 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 complete Freund’s adjuvant (CFA)/collagen II (CII) immunization at day D30 according to Methods. Splenocytes collected at D73 were reactivated in vitro with CII. Supernatants evaluated for protein expression demonstrated increased expression of (A) T-helper type (Th)1-related cytokine interleukin (IL)-5, (B) Th2-related cytokine IL-13, and (C) Th17-related cytokines IL-1β, IL-6, and IL-22 if mice had P. gingivalis infection in addition to CFA/CII immunization. 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.