Viral infection

Abstract

The skin plays a central role in host defense against a broad array of potentially pathogenic microbes, including viruses. Over the past decade, remarkable progress has been made towards understanding the innate immune responses, especially to viral detection. To recognize the invading viruses, various types of cells resident in the skin express many different pattern-recognition receptors (PRRs) such as C-type lectin receptors (CLRs), Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs), retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs), and cytosolic DNA sensors, that can sense the pathogen-associated molecular patterns (PAMPs) of the viruses. Viral recognition by the innate immune system is more challenging than recognition of other pathogen classes, because any given viral protein is unlikely to be shared among diverse viruses. The cutaneous antiviral innate immunity constitutes the first line of host defense that limits the virus dissemination from the skin, and also plays an important role in the activation of adaptive immune response, which represents the second line of defense. More recently, the third immunity "intrinsic immunity" has emerged, providing an immediate and direct antiviral defense mediated by host intrinsic restriction factors. This chapter summarizes the current knowledge of the host antiviral immune systems in the skin, highlighting the innate immunity against skin-associated viruses, and describes how viral components are recognized by cutaneous immune systems.