A ppk2-deficient mutant showed reduced survival at day 7 in activated and naive J774 macrophages relative to the wild-type strain, and naive macrophages showed increased expression of interleukin 2 (IL-2), IL-9, IL-10, IL-12p70, and gamma interferon (IFN-γ) following infection with the mutant relative to those infected with the wild type (Chuang et al., 2013). The gene discussed is IL2; the disease is infection.