Key residues of the receptor binding motif in the spike protein of SARS-CoV-2 that interact with ACE2 and neutralizing antibodies

Coronavirus disease 2019(COVID-19),caused by the novel human coronavirus SARS-CoV-2,is currently a major threat to public health worldwide.The viral spike protein binds the host receptor angiotensin-converting enzyme 2(ACE2)via the receptor-binding domain(RBD),and thus is believed to be a major target to block viral entry.Both SARS-CoV-2 and SARS-CoV share this mechanism.Here we functionally analyzed the key amino acid residues located within receptor binding motif of RBD that may interact with human ACE2 and available neutralizing antibodies.The in vivo experiments showed that immunization with either the SARS-CoV RBD or SARS-CoV-2 RBD was able to induce strong clade-specific neutralizing antibodies in mice;however,the cross-neutralizing activity was much weaker,indicating that there are distinct antigenic features in the RBDs of the two viruses.This finding was confirmed with the available neutralizing monoclonal antibodies against SARS-CoV or SARS-CoV-2.It is worth noting that a newly developed SARS-CoV-2 human antibody,HA001,was able to neutralize SARS-CoV-2,but failed to recognize SARS-CoV.Moreover,the potential epitope residues of HA001 were identified as A475 and F486 in the SARS-CoV-2 RBD,representing new binding sites for neutralizing antibodies.Overall,our study has revealed the presence of different key epitopes between SARS-CoV and SARSCoV-2,which indicates the necessity to develop new prophylactic vaccine and antibody drugs for specific control of the COVID-19 pandemic although the available agents obtained from the SARS-CoV study are unneglectable.

A non-human primate derived anti-P-selectin glycoprotein ligand-1 antibody curtails acute pancreatitis by alleviating the inflammatory responses

Acute pancreatitis(AP)is a devastating disease characterized by an inflammatory disorder of the pancreas.P-selectin glycoprotein ligand-1(PSGL-1)plays a crucial role in the initial steps of the adhesive at process to inflammatory sites,blockade of PSGL-1 might confer potent anti-inflammatory effects.In this study,we generated two non-human primate derived monoclonal antibodies capable of efficiently targeting human PSGL-1,RH001-6 and RH001-22,which were screened from immunized rhesus macaques.We found that RH001-6,can effectively block the binding of P-selectin to PSGL-1,and abolish the adhesion of leukocytes to endothelial cells in vitro.In vivo,we verified that RH001-6 relieved inflammatory responses and pancreatic injury in both caerulein and L-arginine induced AP models.We also evaluated the safety profile after RH001-6 treatment in mice,and verified that RH001-6 did not cause any significant pathological damages in vivo.Taken together,we developed a novel non-human primate derived PSGL-1 blocking antibody with high-specificity,named RH001-6,which can interrupt the binding of PSGL-1 and P-selectin and attenuate inflammatory responses during AP.Therefore,RH001-6 is highly potential to be further developed into therapeutics against acute inflammatory diseases,such as AP.

地区风险文化与企业风险承担

风险文化作为重要的文化维度,深刻地影响公司治理。本文以2008~2014年沪深A股非金融上市公司为研究对象,从地区正式制度、企业制度和管理者风险偏好的角度,考察地区风险文化对企业风险承担的影响。结果发现:在其他条件相同时,地区风险文化通过优化地区金融生态、推进对管理层采用股权激励薪酬制度及提高管理层的风险容忍度,促进企业风险承担。进一步研究发现,当企业外部经济政策不确定性较高、陷入财务困境及管理层自主权较大时,地区风险文化促进企业风险承担的效应较显著。此外,本文还发现地区风险文化更多地体现为冒险精神,通过促进企业风险承担,进而优化企业资源配置效率。本文的研究丰富了文化与金融理论的文献,拓展了风险承担影响因素的研究,有利于深化对正式制度与非正式制度相互作用的理解。

Human IFN-k Inhibited Respiratory RNA Virus Replication Dependent on Cell-to-Cell Interaction in the Early Phase

Background:Interferon kappa(IFN-k)is a type I interferon(IFN-I)that inhibits virus replication by evoking interferon-stimulated genes(ISGs).However,as an evolutionarily ancient interferon,IFN-k may function differently from the later emerged interferon-a and b.Methods:Conventional molecular biology methods were used to determine the localization of IFN-k and its structure and function.In addition,we employed RT-PCR,western blot,and RNA-Seq technologies to characterize the ISGs expression profile and antiviral activities exerted by IFN-k or IFN-a2.Results:Human IFN-k exists in two forms upon ectopic expression,one located on the cell membrane and the other secreted outside the cells.The membrane-anchored IFN-k showed the ability to induce ISGs and curtail RNA virus replication,whereas the secreted IFN-k failed to do so.Structural analyses indicated that 1-27aa at the N-terminus was the signal peptide,and 28-37aa was predicted as the transmembrane region.However,our data demonstrated that both of them were not associated with membrane localization of IFN-k;the former influenced the expression and secretion of IFN-k,and the latter had an impact on the induction of ISGs.In addition,prokaryotic purified soluble mature human IFN-k was also capable of inducing ISGs and inhibiting RNA virus replication.Importantly,human IFN-k induced a faster ISG response but with a lower intensity and a shorter half-life than the response of IFN-a2.In contrast,IFN-a2 started to function later but was stronger and more durable than IFN-k.Conclusions:Human IFN-k-induced ISG response and inhibited respiratory RNA virus replication dependent on cell-to-cell interactions.In addition,compared with IFN-a2,IFN-k exerted effects more rapidly in the early phase,with less intensity and a shorter half-life.Therefore,IFN-k may constitute the first line of IFN-I against respiratory virus infections.