Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the causative virus of the coronavirus disease 2019(COVID-19)pandemic.To establish a safe and convenient assay system for studying entry inhibitors and neu...Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the causative virus of the coronavirus disease 2019(COVID-19)pandemic.To establish a safe and convenient assay system for studying entry inhibitors and neutralizing antibodies against SARS-CoV-2,we constructed a codon-optimized,full-length C-terminal mutant spike(S)gene of SARS-CoV-2.We generated a luciferase(Luc)-expressing pseudovirus containing the wild-type or mutant S protein of SARS-CoV-2 in the envelope-defective HIV-1 backbone.The key parameters for this pseudovirus-based assay,including the S mutants and virus incubation time,were optimized.This pseudovirus contains a Luc reporter gene that enabled us to easily quantify virus entry into angiotensin-converting enzyme 2(ACE2)-expressing 293T cells.Cathepsin(Cat)B/L inhibitor E64d could significantly block SARS-CoV-2 pseudovirus infection in 293T-ACE2 cells.Furthermore,the SARS-CoV-2 spike pseudotyped virus could be neutralized by sera from convalescent COVID-19 patients or recombinant ACE2 with the fused Fc region of human IgG1.Thus,we developed a pseudovirus-based assay for SARS-CoV-2,which will be valuable for evaluating viral entry inhibitors and neutralizing antibodies against this highly pathogenic virus.展开更多
Filoviruses cause severe and fatal viral hemorrhagic fever in humans. Filovirus research has been extensive since the 2014 Ebola outbreak. Due to their high pathogenicity and mortality, live filoviruses require Biosaf...Filoviruses cause severe and fatal viral hemorrhagic fever in humans. Filovirus research has been extensive since the 2014 Ebola outbreak. Due to their high pathogenicity and mortality, live filoviruses require Biosafety Level-4(BSL-4) facilities, which have restricted the development of anti-filovirus vaccines and drugs.An HIV-based pseudovirus cell infection assay is widely used for viral entry studies in BSL-2 conditions. Here,we successfully constructed nine in vitro pseudo-filovirus models covering all filovirus genera and three in vivo pseudo-filovirus-infection mouse models using Ebola virus, Marburg virus, and Lloviu virus as representative viruses. The pseudo-filovirus-infected mice showed visualizing bioluminescence in a dose-dependent manner. A bioluminescence peak in mice was reached on day 5 post-infection for Ebola virus and Marburg virus and on day4 post-infection for Lloviu virus. Two known filovirus entry inhibitors, clomiphene and toremiphene, were used to validate the model. Collectively, our study shows that all genera of filoviruses can be well-pseudotyped and are infectious in vitro. The pseudo-filovirus-infection mouse models can be used for in vivo activity evaluation of anti-filovirus drugs. This sequential in vitro and in vivo evaluation system of filovirus entry inhibitors provides a secure and efficient platform for screening and assessing anti-filovirus agents in BSL-2 facilities.展开更多
With the development of the COVID-19 epidemic,there is an urgent need to establish a system for determining the effectiveness and neutralizing activity of vaccine candidates in biosafety level 2(BSL-2)facilities.Previ...With the development of the COVID-19 epidemic,there is an urgent need to establish a system for determining the effectiveness and neutralizing activity of vaccine candidates in biosafety level 2(BSL-2)facilities.Previously,researchers had developed a pseudotyped virus systemfor SARS-CoV andMERS-CoV,based onHIV-1 core,bearing virus spike protein.During the development of a pseudotyped SARS-CoV-2 system,a eukaryotic expression plasmid expressing SARSCoV-2 spike(S)protein was constructed and then co-transfectedwith HIV-1 based plasmid which containing the firefly luciferase reporter gene,into HEK293T cells to prepare the pseudotyped SARS-CoV-2 virus(ppSARS-2).We have successfully established the pseudotyped SARS-CoV-2 system for neutralization and entry inhibition assays.Huh7.5 cell line was found to be the most susceptible to our pseudotyped virus model.Different levels of neutralizing antibodies were detected in convalescent serum samples of COVID-19 patients using ppSARS-2.The recombinant,soluble,angiotensin-converting enzyme 2 protein was found to inhibit the entry of ppSARS-2 in Huh7.5 cells effectively.Furthermore,the neutralization results for ppSARS-2 were consistent with those of live SARS-CoV-2 and determined using the serum samples fromconvalescent patients.In conclusion,we have developed an easily accessible and reliable tool for studying the neutralizing efficiency of antibodies against SARS-CoV-2 and the entry process of the virus in a BSL-2 laboratory.展开更多
目的建立基于实验设计(Design of Experiment,DOE)的SARS-CoV-2中和抗体相对活性检测方法,并进行验证,以期为SARS-CoV-2中和抗体的研发和质量评价提供可靠的检测方法。方法采用SARS-CoV-2变异株假病毒建立用于评价SARS-CoV-2中和抗体相...目的建立基于实验设计(Design of Experiment,DOE)的SARS-CoV-2中和抗体相对活性检测方法,并进行验证,以期为SARS-CoV-2中和抗体的研发和质量评价提供可靠的检测方法。方法采用SARS-CoV-2变异株假病毒建立用于评价SARS-CoV-2中和抗体相对活性的方法,通过DOE优化细胞密度[(3~5)×10^(5)个/mL]、假病毒滴度(3750~6250 TCID50/mL)、抗体与假病毒中和时间(0.5~1.5 h)、抗体假病毒复合物与细胞作用时间(48~96 h),并验证方法的专属性、线性范围、准确性、精密性。采用优化的方法检测2批SARS-CoV-2中和抗体的相对活性。结果确定最佳细胞密度为4×10^(5)个/mL,假病毒滴度为6250 TCID50/mL,抗体与假病毒中和时间为1.5 h,抗体假病毒复合物与细胞作用时间为96 h。仅SARS-CoV-2中和抗体呈典型量效曲线,抗VEGF单克隆抗体和样品稀释液均未呈现量效曲线;SARS-CoV-2中和抗体理论效价在50%~200%范围内与检测值呈良好的线性关系,线性方程为y=1.0342 x-0.013,r=0.9588;50%、71%、100%、141%和200%相对效价水平样品3次检测结果均值的相对偏倚为-6.2%~7.3%,几何变异系数(geometric coefficient of variation,GCV)为3.2%~16.9%。2批SARS-CoV-2中和抗体相对活性分别为91%和118%。结论建立的方法具有良好的专属性、准确性及精密性,可用于SARS-CoV-2中和抗体相对活性的检测。展开更多
The serum samples and corresponding cervical swabs were collected from 50 women with genital warts from Tianjin city, China. The neutralizing antibodies against HPV-16, -18, -58, -45, -6 and -11 in serum samples were ...The serum samples and corresponding cervical swabs were collected from 50 women with genital warts from Tianjin city, China. The neutralizing antibodies against HPV-16, -18, -58, -45, -6 and -11 in serum samples were tested by using pseudovirus-based neutralization assays and HPV DNAs in cervical swabs were also tested by using a typing kit that can detect 21 types of HPV. The results revealed that 36% （18/50） of sera were positive for type-specific neutralizing antibodies with a titer range of 160-2560, of which 22%（11/50）, 12%（6/50）, 10%（5/50）, 4%（2/50）, 4%（2/50） and 2%（1/50） were against HPVs -6, -16, -18, -58, -45 and -1 l, respectively. Additionally, 60% （30/50） of samples were HPV DNA-positive, in which the most common types detected were HPV-68（18%）, HPV-16（14%）, HPV-58（12%）, HPV-33（8%） and HPV-6, HPV-11, HPV-18 and HPV-52 （6% each）. The concordance between HPV DNA and corresponding neutralizing antibodies was 56% （28/50） with a significant difference （P〈0.05）. The full-length sequences of five HPV types （HPV -42, -52, -53, -58 and -68） were determined and exhibited 98%-100% identities with their reported genomes. The present data may have utility for investigating the natural history of HPV infection and promote the development of HPV vaccines.展开更多
基金This work was supported by the Emergency Project from the Science&Technology Commission of Chongqing(cstc2020jscx-fyzx0053)a Major National Science&Technology Program grant(2017ZX10202203)from the Science&Technology Commission of China,the Leading Talent Program of CQ CSTC(CSTCCXLJRC201719)+1 种基金the Scientific Research Innovation Project for Postgraduate in Chongqing(CYB19168)the Emergency Project for Novel Coronavirus Pneumonia from the Chongqing Medical University(CQMUNCP0302).
文摘Severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is the causative virus of the coronavirus disease 2019(COVID-19)pandemic.To establish a safe and convenient assay system for studying entry inhibitors and neutralizing antibodies against SARS-CoV-2,we constructed a codon-optimized,full-length C-terminal mutant spike(S)gene of SARS-CoV-2.We generated a luciferase(Luc)-expressing pseudovirus containing the wild-type or mutant S protein of SARS-CoV-2 in the envelope-defective HIV-1 backbone.The key parameters for this pseudovirus-based assay,including the S mutants and virus incubation time,were optimized.This pseudovirus contains a Luc reporter gene that enabled us to easily quantify virus entry into angiotensin-converting enzyme 2(ACE2)-expressing 293T cells.Cathepsin(Cat)B/L inhibitor E64d could significantly block SARS-CoV-2 pseudovirus infection in 293T-ACE2 cells.Furthermore,the SARS-CoV-2 spike pseudotyped virus could be neutralized by sera from convalescent COVID-19 patients or recombinant ACE2 with the fused Fc region of human IgG1.Thus,we developed a pseudovirus-based assay for SARS-CoV-2,which will be valuable for evaluating viral entry inhibitors and neutralizing antibodies against this highly pathogenic virus.
基金supported by grants from the National Natural Science Foundation of China (81202568, 81473256, and 81273561)the National Science and Technology Major Project (2015ZX09102-023-004)+1 种基金the CAMS Innovation Fund for Medical Sciences (2016-I2M-1–014)the Beijing Key Laboratory of New Drug Mechanisms and Pharmacological Evaluation Study (BZ0150)
文摘Filoviruses cause severe and fatal viral hemorrhagic fever in humans. Filovirus research has been extensive since the 2014 Ebola outbreak. Due to their high pathogenicity and mortality, live filoviruses require Biosafety Level-4(BSL-4) facilities, which have restricted the development of anti-filovirus vaccines and drugs.An HIV-based pseudovirus cell infection assay is widely used for viral entry studies in BSL-2 conditions. Here,we successfully constructed nine in vitro pseudo-filovirus models covering all filovirus genera and three in vivo pseudo-filovirus-infection mouse models using Ebola virus, Marburg virus, and Lloviu virus as representative viruses. The pseudo-filovirus-infected mice showed visualizing bioluminescence in a dose-dependent manner. A bioluminescence peak in mice was reached on day 5 post-infection for Ebola virus and Marburg virus and on day4 post-infection for Lloviu virus. Two known filovirus entry inhibitors, clomiphene and toremiphene, were used to validate the model. Collectively, our study shows that all genera of filoviruses can be well-pseudotyped and are infectious in vitro. The pseudo-filovirus-infection mouse models can be used for in vivo activity evaluation of anti-filovirus drugs. This sequential in vitro and in vivo evaluation system of filovirus entry inhibitors provides a secure and efficient platform for screening and assessing anti-filovirus agents in BSL-2 facilities.
基金support this work:The National Key Research and Development Program of China(No.2016YFD0500301,No.2020YFC0842100)the National Major Project for Control and Pre-vention of Infectious Disease in China(No.2018ZX10101002).
文摘With the development of the COVID-19 epidemic,there is an urgent need to establish a system for determining the effectiveness and neutralizing activity of vaccine candidates in biosafety level 2(BSL-2)facilities.Previously,researchers had developed a pseudotyped virus systemfor SARS-CoV andMERS-CoV,based onHIV-1 core,bearing virus spike protein.During the development of a pseudotyped SARS-CoV-2 system,a eukaryotic expression plasmid expressing SARSCoV-2 spike(S)protein was constructed and then co-transfectedwith HIV-1 based plasmid which containing the firefly luciferase reporter gene,into HEK293T cells to prepare the pseudotyped SARS-CoV-2 virus(ppSARS-2).We have successfully established the pseudotyped SARS-CoV-2 system for neutralization and entry inhibition assays.Huh7.5 cell line was found to be the most susceptible to our pseudotyped virus model.Different levels of neutralizing antibodies were detected in convalescent serum samples of COVID-19 patients using ppSARS-2.The recombinant,soluble,angiotensin-converting enzyme 2 protein was found to inhibit the entry of ppSARS-2 in Huh7.5 cells effectively.Furthermore,the neutralization results for ppSARS-2 were consistent with those of live SARS-CoV-2 and determined using the serum samples fromconvalescent patients.In conclusion,we have developed an easily accessible and reliable tool for studying the neutralizing efficiency of antibodies against SARS-CoV-2 and the entry process of the virus in a BSL-2 laboratory.
文摘The serum samples and corresponding cervical swabs were collected from 50 women with genital warts from Tianjin city, China. The neutralizing antibodies against HPV-16, -18, -58, -45, -6 and -11 in serum samples were tested by using pseudovirus-based neutralization assays and HPV DNAs in cervical swabs were also tested by using a typing kit that can detect 21 types of HPV. The results revealed that 36% （18/50） of sera were positive for type-specific neutralizing antibodies with a titer range of 160-2560, of which 22%（11/50）, 12%（6/50）, 10%（5/50）, 4%（2/50）, 4%（2/50） and 2%（1/50） were against HPVs -6, -16, -18, -58, -45 and -1 l, respectively. Additionally, 60% （30/50） of samples were HPV DNA-positive, in which the most common types detected were HPV-68（18%）, HPV-16（14%）, HPV-58（12%）, HPV-33（8%） and HPV-6, HPV-11, HPV-18 and HPV-52 （6% each）. The concordance between HPV DNA and corresponding neutralizing antibodies was 56% （28/50） with a significant difference （P〈0.05）. The full-length sequences of five HPV types （HPV -42, -52, -53, -58 and -68） were determined and exhibited 98%-100% identities with their reported genomes. The present data may have utility for investigating the natural history of HPV infection and promote the development of HPV vaccines.
