TLR7 and infection: A more recent study showed that the three nucleic acid sensing TLRs, TLR3, 7 and 9, are crucial for a protective response against L. major infection, as mice which lacked all of these functional TLRs (i.e. TLR3/TLR7/TLR9−/− or UNC93B1−/− mice) were highly susceptible to infection [27].