IL17A and infection: At 17 weeks post-infection, males dosed with C. acnes followed by H. pylori exhibited increased inflammation scores by histopathology; however, males dosed with H. pylori followed by C. acnes exhibited reduced gastric Foxm1, pro-inflammatory cytokine (Il-1β, Ifn-γ, Tnf-α, Il-17a, and iNOS), regulatory cytokine (Foxp3) gene expression, pro-inflammatory IgG2a antibodies, and gastric lymph node RORγT expression compared to H. pylori-monoinfected mice.