Science: Chen Wei and Westlake University identify new crown antibodies to help "cocktail" therapy.

At present, scientists are working hard to develop vaccines and drugs based on the epitopes of new coronavirus (sars-cov-2).this epitope is not only located on the receptor binding domain (RBD) of virus spike glycoprotein (s), but also the whole s protein.recently, academician Chen Wei of the Academy of Military Medical Sciences cooperated with Zhou Qiang Laboratory of West Lake University to isolate and identify monoclonal antibodies (mAbs) from plasma of 10 patients with new crown rehabilitation.it was found that three kinds of monoclonal antibodies could neutralize live neocoronavirus. Among them, a monoclonal antibody named 4a8 showed high ability to live virus and pseudovirus, but did not bind to RBD.the epitope of 4a8 is the N-terminal domain (NTD) of S protein. The research team obtained the frozen electron microscope structure of its complex with S protein, with the overall resolution of 3.1 A and the local resolution of 4 a8-ntd interface of 3.3 a.the team believes that this suggests that NTD is a promising target for therapeutic monoclonal antibodies against the new crown.the research work was published in the top academic journal Science on June 22, local time, entitled "a neutralising human antibody binds to the N-terminal domain of the spike protein of sars-cov-2".the research team includes the Military Medical Research Institute of Academy of Military Sciences, Zhejiang Provincial Key Laboratory of structural biology of Xihu University, and the advanced innovation center of structural biology of Tsinghua University. Besides Zhou Qiang and Chen Wei, the research correspondents also include Li Jianmin of the Academy of military medicine.it is worth mentioning that the team of Zhou Qiang Laboratory of West Lake University has repeatedly analyzed the structure of the new coronavirus and its invasion mechanism. In February, it successfully analyzed the full-length three-dimensional structure of the virus receptor ACE2 and the three-dimensional structure of the S protein and ACE2 complex on the virus surface for the first time in the world.and academician Chen Wei's team has been accelerating the research on vaccine and inhibitor since the beginning of the new epidemic.the newly published research of Chen Wei and Zhou Qiang is divided into two steps: one is to isolate the antibody from the recovered patients with new coronavirus, and the other is to analyze the complex structure of the antibody and the S protein of the new coronavirus.previously, in the study of new coronavirus, drug design mainly targeted RBD (receptor binding domain) of S protein of new coronavirus.but in this study, academician Chen Wei's team found an antibody named 4a8 from the N-terminal domain of S protein.after a number of experimental tests, the researchers found that antibody 4a8 has strong virus neutralization ability and can significantly inhibit the activity of the virus.next, Zhou Qiang laboratory analyzed the high-resolution complex structure of 4a8 antibody and S protein of new coronavirus by freezing electron microscope technology, and the interaction interface between them could be clearly seen.in general, this study reported a completely human neutralizing monoclonal antibody, which could recognize the N-terminal domain epitopes of sars-cov-2s protein, and its functional mechanism was independent of receptor binding inhibition.the team believes that 4a8 combined with RBD targeted antibody may avoid escape mutation of the virus and become a promising "cocktail" therapy. the information obtained from these studies can be used for the development of structure-based vaccine design for sars-cov-2. monoclonal antibody 4a8: the S protein of new coronavirus is responsible for binding with receptor and invading host, which is usually an important target of drug development. during infection, S protein is cleaved into N-terminal S1 subunit and C-terminal S2 subunit by host protease (such as TMPRSS2). S1 and S2 mediate receptor binding and membrane fusion, respectively. among them, S1 contains an N-terminal domain (NTD) and a receptor binding domain (RBD), which is crucial in determining tissue tropism and host range. when the virus invades the human body, RBD binds to the human receptor ACE2 (angiotensin converting enzyme 2), but the function of NTD is not clear. previous studies have shown that the NTD of S protein of Middle East respiratory syndrome coronavirus (mers COV) can be used as a key epitope for antibody neutralization. A novel coronavirus specific monoclonal antibody was isolated from SARS-CoV-2 patients during the convalescence stage. The researchers from Chen Wei academician team obtained 10 monoclonal antibodies from the memory B cells and plasma cells of the recovered patients after the infection of the new coronavirus. The antibody was isolated from 399 patients. binding spectrum of monoclonal antibodies specific to S protein, 35 s protein specific antibodies were screened and found to target at least four antigenic regions of S protein of new coronavirus. it is worth noting that only 4 of the 35 s protein specific antibodies recognize RBD. neutralization ability of monoclonal antibodies next, the researchers tested the affinity of antigen and antibody in vitro in African green monkey kidney cells. They found that antibody 4a8 had higher inhibition than other antibodies after testing RNA load of live virus in African green monkey kidney cells treated with each monoclonal antibody using real-time qPCR (real-time fluorescence quantitative PCR) 。 the researchers then carried out the neutralization experiment of pseudovirus (i.e. the virus without amplification ability but retaining the infection ability). It was found that antibody 4a8 can protect ACE2 cells, has strong virus neutralization ability, and can significantly inhibit the activity of virus. the team believes that 4a8 may be a potential candidate for the treatment of new coronavirus, because 4a8 shows a high level of neutralization ability against both live and Pseudoviruses of sars-cov-2. freeze electron microscopic structure of the complex: targeting the N-terminal domain of the new coronal s protein. In order to study the interaction between antibody 4a8 and virus S protein, the freeze electron microscopic structure of the complex was analyzed with an overall resolution of 3.1. The freeze electron microscopic structure of 4a8 and s-ecd complexes showed that three 4a8 molecules were bound to a trimer s protein, and NTD in each S protein monomer could be bound by 4a8, and the interaction interface was not different. however, it is worth noting that the binding of NTD to antibody 4a8 does not affect the location of RBD in space, nor does it prevent the binding of RBD to cell surface receptor ACE2. Interaction between NTD and 4a8, 4a8 antibody binds to the N-terminal domain (NTD) of S protein of new coronavirus through heavy chain. in the high-resolution structure of the complex, the researchers analyzed three flexible segments of the NTD domain (loop loop region, meaning the region where conformation changes easily). In the previously analyzed structure of the new coronavirus s protein, these sequences were not resolved because of their flexibility. after structural analysis, it was found that the variable region of neutralizing antibody 4a8 interacted with two flexible fragments (N2 and N3), thus stabilizing this part of the structure, and the interaction interface was composed of a wide range of hydrophilic interaction networks. these results suggest that the monoclonal antibodies against SARS cov-2 naturally formed and isolated from human B cells are highly diverse in gene usage and epitope recognition of the virus S protein. it is worth noting that the monoclonal antibodies isolated from most of the convalescent patients can not recognize the RBD region of virus S protein, and all monoclonal antibodies that can neutralize live sars-cov-2 can not inhibit the binding of virus S protein to human ACE2. these results indicate that in addition to inhibiting the interaction between the virus and the receptor, there are other important neutralization mechanisms of sars-cov-2, such as the neutralization mode of binding the N-terminal domain (NTD) of the S protein of 4a8 antibody. the researchers speculated that 4a8 might neutralize sars-cov-2 by inhibiting the conformational changes of S protein. generally speaking, 4a8 is a neutralizing monoclonal antibody completely derived from human body, which can recognize the fragile epitope NTD of virus S protein, and has a virus neutralization mechanism independent of receptor binding inhibition. finally, the researchers pointed out that the combination therapy of 4a8 and RBD targeted antibody can effectively avoid the escape mutation of the virus, and is expected to become a "cocktail" therapy. The information obtained from this study will be conducive to the development of vaccines and drug treatment methods for sars-cov-2. this official account is hosted by the microbiology resource center and the big data center of the Institute of Microbiology, Chinese Academy of Sciences. In 2019, Wen Wen TOP101. reversed , which is a simple disease, reducing weight or reversing the disease. 2. Just now, science released ten scientific breakthroughs in 2019! 3. Science! Broccoli awakens anti-tumor gene! Chinese medical doctor's letter to his father published in Chinese by lancet! Your "honey", my "arsenic..." 6. Drinking, especially those who blush, may face a higher risk of dementia. 7. Nature weighs heavily! The first creature to completely synthesize and completely change the DNA code was born. 8. This is not a big hazelnut! Science has published a new oral insulin, or will replace the traditional injection 9. Science to prevent baldness: start from never losing hair... 10. 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