SARS‐CoV‐2 infection‐induced immune responses: friends or foes?

Li, Keying; Hao, Zhenhua; Zhao, Xiaohui; Du, Jiying; Zhou, Yanlin

Severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is an emerging coronavirus that belongs to the β genus, causing the outbreak of coronavirus disease 19 (COVID‐19). SARS‐CoV‐2 infection can stimulate a pronounced immune response in the host, which embodies in the decrease of lymphocytes and aberrant increase of cytokines in COVID‐19 patients. SARS‐CoV‐2 RNA and proteins interact with various pattern recognition receptors that switch on antiviral immune responses to regulate viral replication and spreading within the host in vivo. However, overactive and impaired immune responses also cause immune damage and subsequent tissue inflammation. This article focuses on the dual roles of immune system during SARS‐CoV‐2 infection, providing a theoretical basic for identifying therapeutic targets in a situation with an unfavorable immune reaction.