Studies in IFN-γR-/- mice (Ross et al., 2013) have demonstrated that IFN-γ can activate macrophages to eliminate intracellular bacteria and play an important role in immune protection against B. pertussis (Higgins et al., 2006) and that IL-17 exerts antibacterial effects by recruiting neutrophils to the site of infection and promoting the synthesis of antibacterial peptides (Ye et al., 2001; Khader et al., 2007). Here, IL17A is linked to infection.