ABSTRACT
The current COVID-19 outbreak was caused by a new coronavirus, SARS-CoV-2. It accesses host cells through the angiotensinconverting enzyme 2 (ACE2) protein, which is expressed by endothelial cells (EC) and very abundantly expressed in the lungs. SARS-CoV-2 uses a surface glycoprotein (peplomer) called a spike to access host cells and ACE2 has been revealed to be a co-receptor for coronavirus entry. The antigen presentation of SARS-CoV mainly depends on the MHC I molecule, but MHC II also contributes to the presentation. Based on the mechanism of a common acute viral infection, the antibody profile against the SARS-CoV virus contains characteristic pattern of IgM and IgG production. By the end of week 12, SARS-specific IgM antibodies disappear, whereas IgG antibodies can last in a longer period of time, which shows IgG antibodies can mainly hold a protective role, and SARS-specific IgG antibodies mainly are S-specific and N-specific antibodies. Clinical manifestations are not only found in mucosa in the airways but also in the cardiovascular system, kidneys, central nervous system, pregnancy, skin, oral cavity and digestive system. The diagnose of clinical presentation of COVID-19 is mainly based on a history of epidemiology, clinical manifestations of pneumonia symptoms (for example, fever, dry cough, myalgia, and shortness of breath) and several additional examinations, include detection of nucleic acids, CT scanning, immune identification technology (POCT) ) IgM / IgG, related to enzymes, immunosorbent assay (ELISA) and blood culture.