After finding that mice with impaired IL-4Rα signaling on CD11c+ cells (CD11ccreIL-4Rα−/lox mice) were susceptible to L. major and showed increased numbers of infected DCs (Hurdayal et al., 2013), we wanted to determine which DC subset, regulated by IL-4, might be important for intracellular multiplication and the spread of L. major parasites during infection, and which effector functions were involved in the phenotype. The gene discussed is IL4; the disease is infection.