In contrast, M28 GAS elicited significant cytokine increases in TNF-α, IL-17A, IL-6, IL-1β, and IL-22, as early as 3 to 7 days post-infection in the estradiol pulse model, and a significant cellular infiltrate in the lumen was observed in colonized WT mice compared to non-infected or IL-17A−/− mice. Here, IL17A is linked to infection.