Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated in...Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated inflammation. We also assume that SARS-CoV-2 likely shares similar inflammatory responses. Potential therapeutic tools to reduce SARS-CoV-2-induced inflammatory responses include various methods to block FcR activation. In the absence of a proven clinical FcR blocker, the use of intravenous immunoglobulin to block FcR activation may be a viable option for the urgent treatment of pulmonary inflammation to prevent severe lung injury. Such treatment may also be combined with systemic anti-inflammatory drugs or corticosteroids. However, these strategies, as proposed here, remain to be clinically tested for effectiveness.展开更多
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
Porcine reproductive and respiratory syndrome virus(PRRSV) shows characteristic antibody-dependent enhancement(ADE) of infection and causes porcine systemic inflammation, which is similar to a type I allergic reaction...Porcine reproductive and respiratory syndrome virus(PRRSV) shows characteristic antibody-dependent enhancement(ADE) of infection and causes porcine systemic inflammation, which is similar to a type I allergic reaction; however, the role of porcine FceεRI in ADE is still unclear. In this study, the expression of different Fc receptors(Fc Rs) on macrophages was investigated in a PRRSV 3D4/21 cell infection model in the presence or absence of PRRSV antibody. The transcription level of Fcc II and FceεRI was significantly up-regulated under PRRSV-antibody complex infection. Internalization and proliferation of PRRSV were promoted by the ADE mechanism when FceεRI was expressed in permissive 3D4/21 cells and the non-permissive cell line HEK 293T. Transcriptome sequencing data showed that the expression levels of AKT,ERK and other signal molecules in the anti-inflammatory pathway were significantly increased, especially in the cells infected with the PRRSV-antibody immune complex. Inflammatory regulatory molecules such as PLA2G6, LOX, TRPM8 and TRPM4 were significantly up-regulated following PRRSV infection but significantly down-regulated in the cells infected with the PRRSV-antibody immune complex. Our results demonstrated that FceεRI could be involved in PRRSV ADE, the antigen presenting process and regulation of the inflammatory response during PRRSV infection, which provides new insights into PRRSV infection mediated by FceεRI and the PRRSV-antibody immune complex.展开更多
After dengue virus(DENV)infection,antibody-dependent enhancement(ADE)is easy to occur when the neutralizing antibody(NAb)gradually decreases to a sub-neutralizing concentration.In this cohort surveillance,we utilized ...After dengue virus(DENV)infection,antibody-dependent enhancement(ADE)is easy to occur when the neutralizing antibody(NAb)gradually decreases to a sub-neutralizing concentration.In this cohort surveillance,we utilized sera samples collected from dengue fever patients at different convalescent phases in Jinghong City,to investigate the dynamic change rule of DENV-specific antibodies,and to analyze the risk of ADE caused by secondary infection with heterologous serotypes DENVs.For baseline serosurvey,191 four-year and 99 six-year sera samples during convalescence were collected in 2017 and 2019,respectively.The positive rate of DENVspecific immunoglobulin G was 98.4%in 2017,which significantly decreased to 82.8%in 2019.The geometric mean titer(GMT)of NAb decreased from 1:155.35 to 1:46.66.Among 290 overall samples,73 paired consecutive samples were used for follow-up serosurvey.In four-year sera,the GMTs of NAb against DENV-3 and cross-reactive antibodies against DENV-1,DENV-2 and DENV-4 were 1:167.70,1:13.80,1:18.54 and 1:45.26,respectively,which decreased to 1:53.18,1:10.30,1:14.60 and 1:8.17 in six-year sera.In age-stratified analysis,due to the increasing number of ADE positive samples from 2017 to 2019 in 31–40 and 51–60 years groups,the risk of ADE in DENV-4 infection was positively associated with the extension of convalescent phase,and the odd ratio was higher than other groups.With the recovery period lengthened,the risk of secondary infection with DENV-1 and DENV-2 was reduced.Our results offer essential experimental data for risk prediction of severe dengue in hyper-endemic dengue areas,and provide crucial scientific insight for the development of effective dengue vaccines.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
文摘Currently there is no effective antiviral therapy for SARS-CoV-2 infection, which frequently leads to fatal inflammatory responses and acute lung injury. Here, we discuss the various mechanisms of SARS-CoV-mediated inflammation. We also assume that SARS-CoV-2 likely shares similar inflammatory responses. Potential therapeutic tools to reduce SARS-CoV-2-induced inflammatory responses include various methods to block FcR activation. In the absence of a proven clinical FcR blocker, the use of intravenous immunoglobulin to block FcR activation may be a viable option for the urgent treatment of pulmonary inflammation to prevent severe lung injury. Such treatment may also be combined with systemic anti-inflammatory drugs or corticosteroids. However, these strategies, as proposed here, remain to be clinically tested for effectiveness.
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.
基金supported by the National Natural Science Foundation of China (31272540)the underprop project of Tianjin Science and Technology Committee in China (16YFZCNC00640)
文摘Porcine reproductive and respiratory syndrome virus(PRRSV) shows characteristic antibody-dependent enhancement(ADE) of infection and causes porcine systemic inflammation, which is similar to a type I allergic reaction; however, the role of porcine FceεRI in ADE is still unclear. In this study, the expression of different Fc receptors(Fc Rs) on macrophages was investigated in a PRRSV 3D4/21 cell infection model in the presence or absence of PRRSV antibody. The transcription level of Fcc II and FceεRI was significantly up-regulated under PRRSV-antibody complex infection. Internalization and proliferation of PRRSV were promoted by the ADE mechanism when FceεRI was expressed in permissive 3D4/21 cells and the non-permissive cell line HEK 293T. Transcriptome sequencing data showed that the expression levels of AKT,ERK and other signal molecules in the anti-inflammatory pathway were significantly increased, especially in the cells infected with the PRRSV-antibody immune complex. Inflammatory regulatory molecules such as PLA2G6, LOX, TRPM8 and TRPM4 were significantly up-regulated following PRRSV infection but significantly down-regulated in the cells infected with the PRRSV-antibody immune complex. Our results demonstrated that FceεRI could be involved in PRRSV ADE, the antigen presenting process and regulation of the inflammatory response during PRRSV infection, which provides new insights into PRRSV infection mediated by FceεRI and the PRRSV-antibody immune complex.
基金supported by the National Natural Science Foundation of China under grants 81772172,U1902210,81972979 and 81902048
文摘After dengue virus(DENV)infection,antibody-dependent enhancement(ADE)is easy to occur when the neutralizing antibody(NAb)gradually decreases to a sub-neutralizing concentration.In this cohort surveillance,we utilized sera samples collected from dengue fever patients at different convalescent phases in Jinghong City,to investigate the dynamic change rule of DENV-specific antibodies,and to analyze the risk of ADE caused by secondary infection with heterologous serotypes DENVs.For baseline serosurvey,191 four-year and 99 six-year sera samples during convalescence were collected in 2017 and 2019,respectively.The positive rate of DENVspecific immunoglobulin G was 98.4%in 2017,which significantly decreased to 82.8%in 2019.The geometric mean titer(GMT)of NAb decreased from 1:155.35 to 1:46.66.Among 290 overall samples,73 paired consecutive samples were used for follow-up serosurvey.In four-year sera,the GMTs of NAb against DENV-3 and cross-reactive antibodies against DENV-1,DENV-2 and DENV-4 were 1:167.70,1:13.80,1:18.54 and 1:45.26,respectively,which decreased to 1:53.18,1:10.30,1:14.60 and 1:8.17 in six-year sera.In age-stratified analysis,due to the increasing number of ADE positive samples from 2017 to 2019 in 31–40 and 51–60 years groups,the risk of ADE in DENV-4 infection was positively associated with the extension of convalescent phase,and the odd ratio was higher than other groups.With the recovery period lengthened,the risk of secondary infection with DENV-1 and DENV-2 was reduced.Our results offer essential experimental data for risk prediction of severe dengue in hyper-endemic dengue areas,and provide crucial scientific insight for the development of effective dengue vaccines.
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.
文摘目的在急性单核细胞白血病细胞(THP-1)水平建立Ⅲ型登革病毒(Dengue virus typeⅢ,DENV-3,DV-3)感染和抗体依赖性增强(antibody dependent enhancement,ADE)感染模型,探讨胞内长链非编码RNA(long non-coding RNA,LncRNA)的差异性表达,绘制竞争性内源RNA(competitive endogenous RNA,CeRNA)调控网络并进行LncRNA翻译功能预测。方法DENV-3感染C6/36细胞6 d后,收获培养上清,采用CCID50法测定病毒滴度,并通过PCR进行型别以及基因组全长扩增鉴定;扩增DENV-3标准质粒,PCR鉴定,绘制标准曲线;将THP-1细胞分为阴性对照(THP-1)、直接感染(DV-3)、ADE及空白对照[1640(-)]组,感染48 h后提取胞内总RNA,测定病毒拷贝数;通过全转录组测序技术,对THP-1 vs DENV-3、THP-1 vs ADE、DENV-3 vs ADE各组中上调和下调前5个的LncRNA进行CeRNA调控网络构建,并分析其编码蛋白的功能。结果DENV-3感染C6/36细胞3 d后有明显的细胞融合、空泡和脱落;病毒滴度约为1.0×10^(4.64)PFU/mL,PCR特异引物鉴定为DENV-3,获得病毒完整的基因序列;ADE组胞内病毒核酸拷贝数明显高于DV-3组和空白对照组;在THP-1 vs DENV-3中,预测到人细胞黏附蛋白相互作用蛋白(cytohesin interacting protein,CYTIP)的表达量出现上调;在THP-1 vs ADE中,预测到驱动蛋白家族成员5A(kinesin family 5A,KIF5A)的表达量下调;在DENV-3 vs ADE中,预测到簇分化抗原9(cluster differentiation antigen 9,CD9)和胰岛素样生长因子2(insulin like growth factor 2,IGF2)的表达量上调。这些差异性的LncRNA均具有开放阅读框(open reading frame,ORF),除了Lnc-SH3BP1和Lnc-RPL41以外,其余的LncRNA均具有内部核糖体结合位点(internal ribosome binding site,IRES)。结论在DENV-3感染THP-1细胞及其介导的ADE感染中,LncRNA的表达发生了明显的差异性改变,且可能通过多种生物学功能调控感染的进程,有助于更深层次理解ADE感染的发生机制。
