Given that a major effect of IL17 is to enhance neutrophil production and mobilization, we hypothesized that the differing effects of IL17 on outcome from infection with these two strains manifest in Figs 3 and 4 could be due to neutrophils enhancing survival in infection with the invasive TIGR4 serotype but increasing mortality in infection with the non-invasive SRL1 strain. Here, IL17A is linked to infection.