Innate immune responses to SARS-CoV-2.

This chapter provides an overview of the innate immune response to SARS-CoV-2, focusing on the recognition, activation, and evasion strategies employed by the virus. The innate immune system plays a crucial role in the early defense against viral infections, and understanding its response to SARS-CoV-2 is essential for developing effective therapeutic approaches. The chapter begins by explaining the basics of the innate immune system, including its components and salient features. It discusses the various pattern recognition receptors involved in recognizing SARS-CoV-2, such as toll-like receptors, RIG-I-like receptors, NOD-like receptors, and other cytosolic sensors. The binding and entry of the virus into host cells and subsequent activation of innate immune cells, including neutrophils, monocytes, macrophages, dendritic cells, NK cells, and ILCs, are explored. Furthermore, the secretion of key cytokines and chemokines, including type I interferons, IL-6, IL-17, and TNF-alpha, is discussed as part of the innate immune response. The concept of PANoptosis, involving programmed cell death mechanisms, is introduced as a significant aspect of the response to SARS-CoV-2. The chapter also addresses the innate immune evasion strategies employed by SARS-CoV-2, which allow the virus to evade or subvert the host immune response, contributing to viral persistence. Understanding these strategies is crucial for developing targeted therapies against the virus.