ive responses is activated. PRRs include Toll-like receptors (TLRs), that are able to recognize viral DNA, viral double-stranded RNA and viral single-stranded RNA. TLRs are expressed on macrophages, dendritic cells, neutrophils, eosinophils, epithelial cells and keratinocytes. In particular, intracellular TLR-7 and TLR-8 allow the innate recognition of t