Too cunning, Chinese and American scholars have confirmed that the new crown virus can use the body's immune system, open the door to invasion, enhance infection and transmission capacity.

As we all know, interferon (IFN), a glycoprotein, is recognized by the immune system in vivo and secreted after virus infection. Interferon can inhibit the proliferation of virus in cells, so it is widely used in antiviral therapy. The novel coronavirus pneumonia epidemic is still raging around the world at, which has resulted in more than 170 thousand deaths and has brought heavy impacts to many countries and people.previous studies have confirmed that NCV invades human cells through two receptors, ACE2 and TMPRSS2. The more cells express these two proteins, the more likely they are to be infected by NCV.on April 22, Harvard Medical School and other dozens of scientific research institutions jointly published a research paper entitled "sars-cov-2 receptor ACE2 is an interference stimulated gene in human airway epithelial cells and is detected in specific cell subsets across tissue.this study found that the expression of ACE2 was increased in human epithelial cells stimulated by interferon.that is to say, the immune system will secrete interferon to inhibit the new coronavirus infection. However, interferon can increase the expression of ACE2, which is exactly the receptor of new coronavirus invading cells.in this way, the interferon secreted by the immune system to suppress the new coronavirus has become a knife for the new coronavirus to tear human cells.it is worth mentioning that as early as February 27, more than a month ago, Wang peihui team of Shandong University reported that ACE2 can be induced by cytokines such as interferon (IFN - β, IFN - γ).in addition, Wang peihui's team also found that SARS CoV, mers CoV and other respiratory viruses, such as rhinovirus rhinovirus and influenza A virus H1N1, could induce the up regulation of ACE2.therefore, they speculated that viral infection activates the immune system and induces the expression of a variety of cytokines, including IFN, which through their receptors activate downstream signaling pathways such as JNK pathway to promote the transcription and expression of ACE2.this indicates that the "cytokine storm" caused by NCV infection can not only cause damage to human organs, but also promote the further infection and transmission of the virus.this research achievement was published in biological preprint biorxiv under the title of increasing host cellular receptor angiotensin converting enzyme 2 (ACE2) expression by coronavirus may facility 2019-ncov infection.Professor Wang peihui, School of advanced medicine, Shandong University, is the corresponding author of the study.this paper has been widely discussed on twitter since biorxiv was launched.cell this paper also explicitly mentioned the previous work of Wang peihui team of Shandong University: it is important that Wang peihui team analyzed the open database and independently found that ACE2 can be used as interferon stimulating gene (ISG) of airway epithelial cells.ACE2 is the main receptor of NCV invading human cells, and is the key factor for the successful infection of NCV.previous studies have shown that high expression of ACE2 can promote neocoronavirus infection, while low expression and non expression can inhibit virus infection and even lead to infection failure. these two studies by the Chinese and American Research Teams show that NCV can further enhance the ability of infection and transmission by inducing the expression of ACE2 on human cell surface. this also explains the abnormal phenomenon that some patients with new crown get worse after using interferon. because these viruses may all use ACE2 as their cellular receptor and enter cells for reproduction and further transmission through ACE2. ACE2 is the "key" for viruses to open host cells. Reducing the expression of ACE2 can prevent viruses from entering cells. therefore, pre storage of drugs that can reduce the expression of ACE2, such as siRNA nucleic acid drugs, can prepare for the possible disease outbreak in the future. novel coronavirus pneumonia, which is generally confirmed by the two studies, indicates that the new crown virus can enhance its ability of infection and transmission by inducing its receptor ACE2 expression. It also suggests that the drugs that reduce ACE2 expression, such as siRNA nucleic acid drugs, may be used for the treatment and prevention of new crown pneumonia. these studies have enlightening significance for understanding the mechanism of new coronavirus successfully infecting host cells, and provide new ideas and scientific basis for the prevention and control of epidemic situation caused by new coronavirus. paper links: