The splenic CD11b+ macrophages from mice at 0, 1, 3, 5, 7, and 9 days post-infection were obtained and used to detect the key markers of classically activated macrophages, inducible nitric oxide synthase (iNOS) and IL (interleukin)-12, and the key markers of alternatively activated macrophages, arginase-1 (Arg1) and IL-10 (Murray et al., 2014). The gene discussed is NOS2; the disease is infection.