Coronavirus Infections and Immune Responses

Coronavirus Infections and Immune Responses

During the end of 2019 and the beginning of 2020, multiple human cases of novel coronavirus infection were reported in relation to theHuanan Seafood Wholesale Market (South China Seafood City Food Market) in Wuhan, China. At 9 o’clock, January 7, 2020, the virus was identified as a novel coronavirus and officially named by the WHO as 2019-nCoV, the new coronavirus in 2019 1. On January 22, 2020, a total of 314 confirmed case have been reported, and 6 patient was reported to have died 2. On January 13, 16 and 21 respectively, Thailand, Japan and Korea confirmed the detection of a human infection with 2019-nCoV from China2. In recent years, novel coronaviruses emerge periodically in different areas around the world. Severe acute respiratory syndrome coronavirus (SARS-CoV) occurred in 2002, which reportedly infected 8,422 This article is protected by copyright. All rights reserved.

people and caused 916 deaths worldwide during the epidemic. Middle East respiratory syndrome coronavirus (MERS-CoV) was first identified in 2012, bringing a total of 1,401 MERS-CoV infections, and 543 (~39%) of which died 34,5. All the infection cases and recent epidemics show that coronaviruses impose a continuous threat to human beings and the economy as they emerge unexpectedly, spread easily, and lead to catastrophic consequences


Since the emergence of SARS-CoV in 2002 and its spread throughout 32 countries and areas, the world has experienced the outbreak of MERS-CoV and now, the 2019-nCoV. All these viruses belong to the subfamily Coronavirinae in the family Coronaviridae. Since CoVs emerge periodically and unpredictably, spread rapidly, and induce serious infectious diseases, they become a continuous threat to human health. This is especially true when there are no approved vaccines or drugs for the treatment of CoV infections and there exist a range of animal reservoirs for CoVs and recombinant CoVs. In recent years, profound understandings of the innate immune response to viruses have been made. This type of immune response inhibits virus replication, promotes virus 

Accepted Articleclearance, induces tissue repair. and triggers prolonged adaptive immune response against the viruses. In most cases, pulmonary and systemic inflammatory responses associated with CoVs are triggered by the innate immune system when it recognizes the viruses. Although a broadly protective, universal vaccine is considered the ultimate protection against the virus spread, vaccine development can be time-consuming. To fulfill the pressing need, we should propose effective therapeutic measures using the accumulated knowledge of the innate immune-response system. Targeted immunotherapy is a good alternative to some antivirals that have narrow treatment windows and meet with drug resistance easily. In 2003, glucocorticoid was widely used in SARS treatment to control pulmonary infection by regulating inflammatory responses. Except for viral pathogenicity, the inflammatory response of the body also plays a crucial role in SARS-induced lung injury cases. Therefore, in CoV pneumonia cases, it is important to control cytokine production and inflammatory response, given that they are responsible for the accumulation of cells and fluids. This strategy is challenging as we have not yet clearly identified any features in an immune response that can be inhibited specifically without compromising the beneficial host defense. However, accomplishing this is not impossible. Notable achievements have been made in analyzing detrimental and protective mechanisms. For instance, completelyblocking a proximal event in the immune response (e.g., activation of IFN response-related PRRs) seems unwise considering its general role in regulating the host





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Accepted Article5. World Health Organization.Middle East respiratory syndrome coronavirus (MERS-CoV). Available from: https://www.who.int/emergencies/mers-cov/en/


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