Although TLR7−/− mice clear LCMV-Armstrong (LCMV-ARM; model of acute infection), they do not clear LCMV-clone 13 (LCMV-CL13; model of chronic infection) infection [25], indicating a requirement for TLR7-mediated signalling to ultimately activate the adaptive immune responses necessary to clear chronic viral infection. This evidence concerns the gene TLR7 and viral infectious disease.