Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV an...Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV and highly pathogenic PRRSV(HP-PRRSV)are the dominant epidemic strains in China;however,commercial vaccines do not always provide sufficient cross-protection,and the reasons for insufficient protection are unclear.This study isolated a wild-type NADC30-like PRRSV,SX-YL1806,from Shaanxi Province.Vaccination challenge experiments in piglets showed that commercial modified live virus(MLV)vaccines provided good protection against HP-PRRSV.However,it could not provide sufficient protection against the novel strain SXYL1806.To explore the reasons for this phenomenon,we compared the genomic homology between the MLV strain and HP-PRRSV or NADC30-like PRRSV and found that the MLV strain had a lower genome similarity with NADC30-like PRRSV.Serum neutralization assay showed that MLV-immune serum slightly promoted the homologous HP-PRRSV replication and significantly promoted the heterologous NADC30-like PRRSV strain replication in vitro,suggesting that antibody-dependent enhancement(ADE)might also play a role in decreasing MLV protective efficacy.These findings expand our understanding of the potential factors affecting the protective effect of PRRSV MLV vaccines against the NADC30-like strains.展开更多
Antibody dependant enhancement refers that viral infectivity was unexpectedly enhanced at low antibody concentration compared to when antibodies were absent,such as Dengue,Zika and influenza virus.To mathematically de...Antibody dependant enhancement refers that viral infectivity was unexpectedly enhanced at low antibody concentration compared to when antibodies were absent,such as Dengue,Zika and influenza virus.To mathematically describe switch from enhancement to neutralisation with increase of antibody concentration,one hyperbolic tangent variant is used as switching function in existed models.However,switching function with hyperbolic tangent contains four parameters,and does not always increase with antibody concentration.To address this problem,we proposed a monotonically increasing Logistical function variant as switching function,which only contains position parameter and magnitude parameter.Analysing influenza viral titre estimated from 21 focus reduction assay(FRA)datasets from neutralisation group(viral titre lower than negative control on all serial dilutions)and 20 FRA dataset from enhancement group(viral titre higher than negative control on high serial dilution),switching function with Logistic function performs better than existed model independent of both groups and exhibited different behaviour/character;specifically,magnitude parameter estimated from enhancement group is lower,but position parameter estimated from enhancement group is higher.A lower magnitude parameter refers that enhancement group more rapidly switches from enhancement to neutralisation with increase of antibody concentration,and a higher position parameter indicates that enhancement group provides a larger antibody concentration interval corresponding to enhancement.Integrating estimated neutralisation kinetics with viral replication,we demonstrated that antibody-induced bistable influenza kinetics exist independent of both groups.However,comparing with neutralisation group,enhancement group provides higher threshold value of antibody concentration corresponding to influenza infectivity.This explains the observed phenomenon that antibody dependent enhancement enhances susceptibility,severity,and mortality to influenza infection.On population level,antibody dependant enhancement can promote H1N1 and H3N2 influenza virus cooperate to sustain long-term circulation on human populations according to antigenic seniority theory.展开更多
Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus(DENV) without enhancing activity in B...Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus(DENV) without enhancing activity in BALB/c mice. Methods: We constructed pFUSE-based vectors(pFUSE1 G7 C2hVH and pFUSE1 G7 C2hVL) containing genes encoding the variable domains of the heavy or light chain of the anti-dengue virus antibody 1 G7 C2, a human IgG1 that has been characterized for its neutralizing activity to DENV-1-4. Leucine(L) at positions 234 and 235 on the Fc CH2 domain in pFUSE1 G7 C2hVH was mutated to alanine(A)(LALA mutation) by site direct mutagenesis, and the new plasmid was termed pFUSE1 G7 C2hVHLALA. An equal amount of pFUSE1 G7 C2hVL and 1 G7 C2hG1-LALA plasmids were co-transfected into Chinese hamster ovary cells(CHO-K1) and a single dose of 100 μg 1 G7 C2hG1-LALA plasmid was intramuscularly injected, followed by electroporation in BALB/c mice. The secreted 1 G7 C2hG1-LALA antibodies in cell culture supernatant and mouse serum were examined for their biological functions, neutralization and enhancing activity. Results: The co-transfection of heavy-and light-chain 1 G7 C2hG1-LALA plasmids in CHO-K1 cells produced approximately 3 900 ng/mL human IgG and neutralized 90%-100% all four DENV, with no enhancing activity. Furthermore, the modified human IgG was produced more than 1 000 ng/mL in mouse serum on day 7 post plasmid injection and showed cross-neutralization to four DENV serotypes. Subsequently, antibody production and neutralization decreased rapidly. Nevertheless, the secreted neutralizing 1 G7 C2hG1-LALA in mouse serum demonstrated complete absence of enhancing activities to all DENV serotypes. Conclusions: These findings reveal that a new modified 1 G7 C2h G1-LALA expressing plasmid based on gene transfer is a possible therapeutic antibody candidate against DENV infection.展开更多
Plasmonic enhanced fluorescence(PEF)technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays(IFMA),however,current approaches to constructing PEF platforms are either expensive/ti...Plasmonic enhanced fluorescence(PEF)technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays(IFMA),however,current approaches to constructing PEF platforms are either expensive/time-consuming or reliant on specialized instruments.Here,we develop a completely alternative approach relying on a two-step protocol that includes the self-assembly of gold nanoparticles(GNPs)at the water–oil interface and subsequent annealing-assisted regulation of gold nanogap.Our optimized thermal-annealing GNPs(TA-GNP)platform generates adequate hot spots,and thus produces high-density electromagnetic coupling,eventually enabling 240-fold fluorescence enhancement of probed dyes in the near-infrared region.For clinical detection of human samples,TA-GNP provides super-high sensitivity and low detection limits for both hepatitis B surface antigen and SARS-CoV-2 binding antibody,coupled with a much-improved detection dynamic range up to six orders of magnitude.With fast detection,high sensitivity,and low detection limit,TA-GNP could not only substantially improve the outcomes of IFMA-based precision medicine but also find applications in fields of proteomic research and clinical pathology.展开更多
Dear Editor,Antibody-dependent enhancement（ADE）has long been recognized for dengue virus（DENV）in vitro and in vivo.It is now clear that antibodies to DENV can also enhance Zika virus（ZIKV）infection in vitro,and ...Dear Editor,Antibody-dependent enhancement（ADE）has long been recognized for dengue virus（DENV）in vitro and in vivo.It is now clear that antibodies to DENV can also enhance Zika virus（ZIKV）infection in vitro,and vice versa（Dejnirattisai et al.,2016;Stettler et al.,2016）.The characteristics of enhancing antibodies,however,remain elusive.展开更多
基金This research was supported by the National Natural Science Foundation of China(32172846)the Earmarked Fund for CARS-35,the Science and Technology Major Project of Gansu Province(22ZD6NA001)+4 种基金the Science Foundation for Distinguished Young Scholars of Shaanxi Province(2021JC-18)the Natural Science Foundation of Gansu Province(23JRRA1153)the Science and Technology Plan Project of Gansu Province(23JRRA561)the Chinese Academy of Agricultural Science and Technology Innovation Project(CAAS-ASTIP-JBGS-20210602)the Strategic Priority Research Program of the National Center of Technology Innovation for Pigs(NCTIP-XD/C03).
文摘Porcine reproductive and respiratory syndrome(PRRS)is one of the most significant diseases affecting the pig industry worldwide.The PRRSV mutation rate is the highest among the RNA viruses.To date,NADC30-like PRRSV and highly pathogenic PRRSV(HP-PRRSV)are the dominant epidemic strains in China;however,commercial vaccines do not always provide sufficient cross-protection,and the reasons for insufficient protection are unclear.This study isolated a wild-type NADC30-like PRRSV,SX-YL1806,from Shaanxi Province.Vaccination challenge experiments in piglets showed that commercial modified live virus(MLV)vaccines provided good protection against HP-PRRSV.However,it could not provide sufficient protection against the novel strain SXYL1806.To explore the reasons for this phenomenon,we compared the genomic homology between the MLV strain and HP-PRRSV or NADC30-like PRRSV and found that the MLV strain had a lower genome similarity with NADC30-like PRRSV.Serum neutralization assay showed that MLV-immune serum slightly promoted the homologous HP-PRRSV replication and significantly promoted the heterologous NADC30-like PRRSV strain replication in vitro,suggesting that antibody-dependent enhancement(ADE)might also play a role in decreasing MLV protective efficacy.These findings expand our understanding of the potential factors affecting the protective effect of PRRSV MLV vaccines against the NADC30-like strains.
文摘Antibody dependant enhancement refers that viral infectivity was unexpectedly enhanced at low antibody concentration compared to when antibodies were absent,such as Dengue,Zika and influenza virus.To mathematically describe switch from enhancement to neutralisation with increase of antibody concentration,one hyperbolic tangent variant is used as switching function in existed models.However,switching function with hyperbolic tangent contains four parameters,and does not always increase with antibody concentration.To address this problem,we proposed a monotonically increasing Logistical function variant as switching function,which only contains position parameter and magnitude parameter.Analysing influenza viral titre estimated from 21 focus reduction assay(FRA)datasets from neutralisation group(viral titre lower than negative control on all serial dilutions)and 20 FRA dataset from enhancement group(viral titre higher than negative control on high serial dilution),switching function with Logistic function performs better than existed model independent of both groups and exhibited different behaviour/character;specifically,magnitude parameter estimated from enhancement group is lower,but position parameter estimated from enhancement group is higher.A lower magnitude parameter refers that enhancement group more rapidly switches from enhancement to neutralisation with increase of antibody concentration,and a higher position parameter indicates that enhancement group provides a larger antibody concentration interval corresponding to enhancement.Integrating estimated neutralisation kinetics with viral replication,we demonstrated that antibody-induced bistable influenza kinetics exist independent of both groups.However,comparing with neutralisation group,enhancement group provides higher threshold value of antibody concentration corresponding to influenza infectivity.This explains the observed phenomenon that antibody dependent enhancement enhances susceptibility,severity,and mortality to influenza infection.On population level,antibody dependant enhancement can promote H1N1 and H3N2 influenza virus cooperate to sustain long-term circulation on human populations according to antigenic seniority theory.
基金supported by the Faculty of Tropical Medicine,Mahidol University,Thailand,Research Fund through a Research and Researcher for Industry(RRi,Grant Number PHD59I0063 for SB)TRF Grant for New Researcher(TRG,Grant Number TRG5980015 for CP)the Office of the National Research Council of Thailand-Japan Society for the Promotion of Science(JSPS)or NRCT-JSPS
文摘Objective: To evaluate the expression of DNA plasmid-harboring modified antibody gene that produces neutralizing human monoclonal antibodies against four serotypes of dengue virus(DENV) without enhancing activity in BALB/c mice. Methods: We constructed pFUSE-based vectors(pFUSE1 G7 C2hVH and pFUSE1 G7 C2hVL) containing genes encoding the variable domains of the heavy or light chain of the anti-dengue virus antibody 1 G7 C2, a human IgG1 that has been characterized for its neutralizing activity to DENV-1-4. Leucine(L) at positions 234 and 235 on the Fc CH2 domain in pFUSE1 G7 C2hVH was mutated to alanine(A)(LALA mutation) by site direct mutagenesis, and the new plasmid was termed pFUSE1 G7 C2hVHLALA. An equal amount of pFUSE1 G7 C2hVL and 1 G7 C2hG1-LALA plasmids were co-transfected into Chinese hamster ovary cells(CHO-K1) and a single dose of 100 μg 1 G7 C2hG1-LALA plasmid was intramuscularly injected, followed by electroporation in BALB/c mice. The secreted 1 G7 C2hG1-LALA antibodies in cell culture supernatant and mouse serum were examined for their biological functions, neutralization and enhancing activity. Results: The co-transfection of heavy-and light-chain 1 G7 C2hG1-LALA plasmids in CHO-K1 cells produced approximately 3 900 ng/mL human IgG and neutralized 90%-100% all four DENV, with no enhancing activity. Furthermore, the modified human IgG was produced more than 1 000 ng/mL in mouse serum on day 7 post plasmid injection and showed cross-neutralization to four DENV serotypes. Subsequently, antibody production and neutralization decreased rapidly. Nevertheless, the secreted neutralizing 1 G7 C2hG1-LALA in mouse serum demonstrated complete absence of enhancing activities to all DENV serotypes. Conclusions: These findings reveal that a new modified 1 G7 C2h G1-LALA expressing plasmid based on gene transfer is a possible therapeutic antibody candidate against DENV infection.
基金supported by the National Natural Science Foundation of China(Nos.21975098 and 22275071)the program for JLU Science and Technology Innovative Research Team(No.2017TD-06)the opening funds of State Key Laboratory of Applied Optics,Changchun Institute of Optics,Fine Mechanics and Physics,Chinese Academy of Science,and the China Postdoctoral Science Foundation(Nos.2020TQ0119 and 2020M681046).
文摘Plasmonic enhanced fluorescence(PEF)technology is a powerful strategy to improve the sensitivity of immunofluorescence microarrays(IFMA),however,current approaches to constructing PEF platforms are either expensive/time-consuming or reliant on specialized instruments.Here,we develop a completely alternative approach relying on a two-step protocol that includes the self-assembly of gold nanoparticles(GNPs)at the water–oil interface and subsequent annealing-assisted regulation of gold nanogap.Our optimized thermal-annealing GNPs(TA-GNP)platform generates adequate hot spots,and thus produces high-density electromagnetic coupling,eventually enabling 240-fold fluorescence enhancement of probed dyes in the near-infrared region.For clinical detection of human samples,TA-GNP provides super-high sensitivity and low detection limits for both hepatitis B surface antigen and SARS-CoV-2 binding antibody,coupled with a much-improved detection dynamic range up to six orders of magnitude.With fast detection,high sensitivity,and low detection limit,TA-GNP could not only substantially improve the outcomes of IFMA-based precision medicine but also find applications in fields of proteomic research and clinical pathology.
基金supported by National Key Program Project Grant of Ministry of Science and Technology of China(2016YFC1201000)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDBP 030405)grants from the Municipal Science and Technology Bureau Foundation of Guangzhou(2014Y2-00550,201508020263)
文摘Dear Editor,Antibody-dependent enhancement（ADE）has long been recognized for dengue virus（DENV）in vitro and in vivo.It is now clear that antibodies to DENV can also enhance Zika virus（ZIKV）infection in vitro,and vice versa（Dejnirattisai et al.,2016;Stettler et al.,2016）.The characteristics of enhancing antibodies,however,remain elusive.
