Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain （VHH）. The recombinant VHHs have a high p...Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain （VHH）. The recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. In particular, they might be very useful for molecular mimicry. The present study demonstrated an alpaca immunized with the F（ab＇）z fragment of anti-aflatoxin B1 mAb and developed an important anti-idiotypic （anti-ld） responses. Antigen-specific elution method was used for panning private anti-ld VHHs from the constructed alpaca VHH library. The selected VHHs were expressed, renatured, purified, and then identified by a competitive enzyme-linked immunosorbent assay （ELISA）. Our findings indicated that the VHH would be an alternative tool for haptens mimicry studies.展开更多
It is well established that all camelids have unique antibodies circulating in their blood.Unlike antibodies from all other species,these special antibodies are devoid of light chains,and are composed of a heavy chain...It is well established that all camelids have unique antibodies circulating in their blood.Unlike antibodies from all other species,these special antibodies are devoid of light chains,and are composed of a heavy chain homodimer.These so-called heavy-chain antibodies(HCAbs)are expressed after a V-D-J rearrangement and require dedicated constant gamma genes. An immune response is raised in these HCAbs following a classical immunization protocol.These HCAbs are easily purified from serum,and their antigen-binding fragment interacts with parts of the target that are less antigenic to conventional antibodies.The antigen binding site of the dromedary HCAb comprises one single domain,referred to as VHH or nanobody(Nb),therefore,a strategy was designed to clone the Nb repertoire of an immunized dromedary and to select the Nb with specificity for our target antigens.The monoclonal Nb is produced well in bacteria,is very stable and highly soluble,and it binds the antigen with high affinity and specificity.Currently,the recombinant Nb has been developed successfully for research purposes, as a probe in biosensors,to diagnose infections,or to treat diseases such as cancer or trypanosomiasis.展开更多
Severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a newly identified member of the coronavirus family that has caused the coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting...Severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a newly identified member of the coronavirus family that has caused the coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting SARS-CoV-2has disrupted the lives and livelihoods of millions worldwide. As of 23 August 2021, a total of 211,373,303 COVID-19cases have been confirmed globally with a death toll of 4,424,341. A strong understanding of the infection pathway of SARS-CoV-2, and how our immune system responds to the virus is highly pertinent for guiding the development and improvement of effective treatments. In this review, we discuss the current understanding of neutralising antibodies(NAbs) and their implications in clinical practice. The aspects include the pathophysiology of the immune response,particularly humoral adaptive immunity and the roles of NAbs from B cells in infection clearance. We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting—from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.展开更多
The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At...The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At the same time,TP53 is the most frequently mutated gene in human cancers.Mutant p53 proteins lose wild-type p53 tumor suppression functions but acquire new oncogenic properties,among which are deregulating cell proliferation,increasing chemoresistance,disrupting tissue architecture,and promoting migration,invasion and metastasis as well as several other pro-oncogenic activities.The oncogenic p53 mutation Y220C creates an extended surface crevice in the DNA-binding domain destabilizing p53 and causing its denaturation and aggregation.This cavity accommodates stabilizing small molecules that have therapeutic values.The development of suitable small-molecule stabilizers is one of the therapeutic strategies for reactivating the Y220C mutant protein.In this review,we summarize approaches that target p53-Y220C,including reactivating this mutation with small molecules that bind Y220C to the hydrophobic pocket and developing immunotherapies as the goal for the near future,which target tumor cells that express the p53-Y220C neoantigen.展开更多
AIM: To investigate the role of P-selectin, intercellular adhesion molecule-1 (ICAM-1) and dendritic cells (DCs)in liver/kidney of rats with hepatic/renal ischemiareperfusion injury and the preventive effect of anti-P...AIM: To investigate the role of P-selectin, intercellular adhesion molecule-1 (ICAM-1) and dendritic cells (DCs)in liver/kidney of rats with hepatic/renal ischemiareperfusion injury and the preventive effect of anti-Pselectin lectin-EGF domain monoclonal antibody (anti-PsLEGFmAb) on the injury.METHODS: Rat models of hepatic and renal ischemiareperfusion were established. The rats were then divided into two groups, one group treated with anti-PsL-EGFmAb(n = 20) and control treated with saline (n = 20). Both groups were subdivided into four groups according to reperfusion time (1, 3, 6 and 24 h). The sham-operated group (n = 5) served as a control group. DCs were observed by the microscopic image method, while P-selectin and ICAM-1 were analyzed by immunohistochemistry.RESULTS: P-selectin increased significantly in hepatic sinusoidal endothelial cells and renal tubular epithelial cells 1 h after ischemia-reperfusion, and the expression of ICAM-1 was up-regulated in hepatic sinusoid and renal vessels after 6 h. CD1a+CD80+DCs gradually increased in hepatic sinusoidal endothelium and renal tubules and interstitium 1 h after ischemia-reperfusion, and there was the most number of DCs in 24-h group. The localization of DCs was associated with rat hepatic/renal function.These changes became less significant in rats treated with anti-PsL-EGFmAb.CONCLUSION: DCs play an important role in immune pathogenesis of hepatic/renal ischemia-reperfusion injury.Anti-PsL-EGFmAb may regulate and inhibit local DC immigration and accumulation in liver/kidney.展开更多
Objective:To isolate and characterize Staphylococcus aureus(S.aureus)β-hemolysinneutralizing dAbs from phage display library of Indian desert camel.Methods:Phage display library of 5×10 dAb clones of LPS-immuniz...Objective:To isolate and characterize Staphylococcus aureus(S.aureus)β-hemolysinneutralizing dAbs from phage display library of Indian desert camel.Methods:Phage display library of 5×10 dAb clones of LPS-immunized Indian desert camel constructed in our laboratory was used for selection of S.aureus exotoxin-specific clones by panning technique.Enrichment of Ag-specific clones in successive rounds of panning was assessed by phage-ELISA and phage titration.Different dAb clones binding to S.aureus exotoxin Ags were expressed with C-terminal 6×His tag in E.coli and purified by Ni-chelate chromatography.The expression was verified by SDS-PAGE and western blotting.The purified clones were tested for inhibition of ’hot-cold’ hemolytic activity in vitro.Resistance to thermal inactivation of the dAb clones was studied by observing the effect of heat treatment from 50℃to 99℃for 30 min on the ’hot-cold’ hemolytic activity in vitro.Results:Several dAb clones binding to S.aureus exotoxins were isolated and enriched by three rounds of panning.The soluble dAb clones were approximately～16 kDa in size and reacted with 6×His tag specific murine monoclonal antibody in western blot.One of the Ni-chelate affinity purified dAb.6×His clones,inhibited S.aureusβ-hemolysin activity in vitro and resisted thermal inactivation upto 991.Conclusions:An S.aureusβ-hemolysinneutralizing dAb clone of possible therapeutic potential has been isolated.展开更多
Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus closely related to the human pathogens including yellow fever virus, dengue virus and West Nile virus. There are currently no effective antiviral therap...Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus closely related to the human pathogens including yellow fever virus, dengue virus and West Nile virus. There are currently no effective antiviral therapies for all of the flavivirus and only a few highly effective vaccines are licensed for human use. In this paper, the E protein domain III (DIII) of six heterologous flaviviruses (DENV1-4, WNV and JEV) was expressed in Escherichia coli successfully. The proteins were purified after a solubilization and refolding procedure, characterized by SDS-PAGE and Western blotting. Competitive inhibition showed that all recombinant flavivirus DIII proteins blocked the entry of JEV into BHK-21 cells. Further studies indicated that antibodies induced by the soluble recombinant flavivirus DIII partially protected mice against lethal JEV challenge. These results demonstrated that recombinant flavivirus DIII proteins could inhibit JEV infection competitively, and immunization with proper folding flavivirus DIII induced cross-protection against JEV infection in mice, implying a possible role of DIII for the cross-protection among flavivirus as well as its use in antigens for immunization in animal models.展开更多
Objective To investigate the expression of discoidin domain receptor 2 (DDR2) of fibroblast-like synovial cells in im- proved adjuvant-induced animal (AIA) model for rheumatoid arthritis (RA) and to provide evidence f...Objective To investigate the expression of discoidin domain receptor 2 (DDR2) of fibroblast-like synovial cells in im- proved adjuvant-induced animal (AIA) model for rheumatoid arthritis (RA) and to provide evidence for DDR2’s antagonist use clinically. Methods AIA was modified by administrating 0.1 mL of complete Freund’s adjuvant (CFA, mixed with 5 mg Bacillus Calmette-Guerin vaccine/mL) into rats’ right hind paws and 0.125 mL tumor necrosis factor-α (2 U/mL) into right ankles and subpatellar fatty tissue. The expression of DDR2 in fibroblast-like synovial cells was assessed using immunohistochemistry, immunofluorescence histochemistry, and in situ hybridization methods. Levels of anti-collagen II antibody were measured using enzyme-linked immunosorbent assay. Results Given the terms mentioned above, we found a more practical rat model, apparently decreasing immunization time (average 3-5 days). DDR2 can be detected upon the 15th day of immunization; expression gradually increased with time going on, and reaching a peak 35 days after immunization before gradually decreasing. Serum anti-collagen II antibody showed similar expression patterns as DDR2, but reached peak later than DDR2, about 40 days after immunization. Conclusion Regular expression of DDR2 in animal models infers its important role in the pathological process of RA.展开更多
Dendritic cells(DCs) are professinal antigen-presenting cells with the ability to initiate primary Tcell responses. While it iswell known that inflammatory stimuli induce the functional maturation of immature DCs, whe...Dendritic cells(DCs) are professinal antigen-presenting cells with the ability to initiate primary Tcell responses. While it iswell known that inflammatory stimuli induce the functional maturation of immature DCs, whether adhesion molecule selectins regulate DCmaturation is poorly understood. Using anti-P-selectin lectin-EGF domain monoclonal antibody (PsL-EGFmAb) that blocks the adhesionof P-, E-, and L-selectin, we demonstrate herein that selectins play important role in stimulating functional maturation of immature DCs.Immature DCs are generated from human cord blood CD34+hematopoietic stem/progenitor cells that were cultured in the presence of stemcell factor, Fms-like tyrosine-kinase-3 ligand, granulocyte-macrophage colony stimulating factor, and transform growth factor-β1. Whenstimulated with tumor necrosis factor-alpha(TNF-α), immature DCs differentiated into mature DCs, producing increased levels of costim-ulatory molecules and interleukin (IL)-12 and obtaining the ability to potently activate naive Tcells. Interestingly, in contrast to matureDCs derived from TNF-α-induced immature DC cultures without PsL-EGFmAb, immature DCs treated with PsL-EGFmAb for7 days werecompletely blocked their maturation, as evidenced by decreased expression of costimulatory molecules CD80, CD86, and CD83, inhibi-ted production of IL-12, and inability to activate naive Tcellsin vitro. Thus, blockade of selectins using PsL-EGFmAb will prove to bea valuable tool for the study of the molecuar mechanisms of DC maturation, as well as for the prevention and treatment of DC-mediated au-toimmunity.展开更多
This study focuses on the expression of human protein tyrosine phosphatase 1B （PTP1 B） catalytic domain （△PTP1B） and preparation of polyclonal antibody against △PTP1B. △PTP1B gene was PCR amplified with the cDN...This study focuses on the expression of human protein tyrosine phosphatase 1B （PTP1 B） catalytic domain （△PTP1B） and preparation of polyclonal antibody against △PTP1B. △PTP1B gene was PCR amplified with the cDNA of human PTP1B as the template, and cloned into the pT7 expression vector. The recombinant pT7-△PTP1B was expressed in E. eoli Rosetta（ DE3 ） host cells and purified. The antiserum was prepared by immunizing rabhit with purified recombinant △PTP1B. The polyclonal antibody against △PTP1B was purified by PVDF immobilized antigen affinity chromatography. △PTP1B was correctly cloned, expressed, and purified as confirmed by PCR, DNA sequence analysis, SDS-PAGE western blotting, and ILPLC. The titer and sensitivity of the antibody were 1：2500（ volume ratio） and 0. 1 ng, respectively. This study provides an important basis for further studying the biological function of PTP1B and its relationship with human diseases.展开更多
Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pa...Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.展开更多
Obejective The domainⅢof dengue virus type 2 envelope was cloned and expressed in Escherichia coli and the inhibited effects of recombinant protein on virus was detected. Methods In this study, the domainⅢ(DⅢ) pro...Obejective The domainⅢof dengue virus type 2 envelope was cloned and expressed in Escherichia coli and the inhibited effects of recombinant protein on virus was detected. Methods In this study, the domainⅢ(DⅢ) protein of the dengue virus type-2 (DENV-2) envelope (E) antigen was expressed in Escherichia coli by fusion with a carrier protein. The protein was puriifed using enzymatic cleavage and afifnity puriifcation. Rabbit immunization and antibody detection was carried out. Inhibition of DENV-2 infection was observed by DENV-2 EDⅢprotein and its immunity rabbits serum. Results The recombinant expression DENV-2 EDⅢ protein plasmid was constructed successfully. After isopropyl thiogalactoside induction, a speciifc soluble 29 kD protein was obtained, and the expression product accounted for 68.87%of the total protein of the cell lysate. Western blot demonstrated the reactivity of the recombinant protein with his-tag and DENV (Ⅰ-Ⅳ) monoclonal antibodies. The protein was puriifed using enzymatic cleavage and affinity purification. The purified recombinant EDⅢ protein inhibited the entry of DENV-2 into BHK-21 cells. DENV-2 plaque neutralization assays were carried out using serially diluted antibodies against EDⅢprotein. At a 1︰16 dilution, the antibodies produced at least 90%neutralization of the DENV-2 virus. Furthermore, the antibodies continued to exhibit high neutralization effects (approximately 80%) until the anti-EDⅢantibody titer reached 1︰1 024. Conclusions DENV-2 EDⅢwas cloned and expressed successfully. DENV-2 EDⅢprotein could be useful in the development of inexpensive dengue vaccine. The data also suggested that DENV-2 employed an attachment molecule or receptor for its entry into C6/36 mosquito cells.展开更多
Screening humanized antibodies from a human Fab phage display library is an effective and quick method to obtain beta-amyloid oligomers. Thus, the present study prepared amyloid-beta 42 oli- gomers and constructed a h...Screening humanized antibodies from a human Fab phage display library is an effective and quick method to obtain beta-amyloid oligomers. Thus, the present study prepared amyloid-beta 42 oli- gomers and constructed a have human Fab phage display library based on blood samples from six healthy people. After three rounds of biopanning in vitro, a human single-domain antibody that spe- cifically recognized amyloid-beta 42 oligomers was identified. Western blot and enzyme-linked im- munosorbent assay demonstrated this antibody bound specifically to human amyloid-beta 42 tetramer and nonamer, but not the monomer or high molecular weight oligomers. This study suc- cessfully constructed a human phage display library and screened a single-domain antibody that specifically recognized amyloid-beta 42 oligomers.展开更多
基金supported by a grant from the National Basic Research Program of China(2013CB127804)the National Natural Science Funds(31171696,China)the Research Program of the State Key Laboratory of Food Science and Technology,Nanchang University(SKLF-MB-201002)
文摘Some unique subclasses of Camelidae antibodies are devoid of the light chain, and the antigen binding site is comprised exclusively of the variable domain of the heavy chain （VHH）. The recombinant VHHs have a high potential as alternative reagents for the next generation of immunoassay. In particular, they might be very useful for molecular mimicry. The present study demonstrated an alpaca immunized with the F（ab＇）z fragment of anti-aflatoxin B1 mAb and developed an important anti-idiotypic （anti-ld） responses. Antigen-specific elution method was used for panning private anti-ld VHHs from the constructed alpaca VHH library. The selected VHHs were expressed, renatured, purified, and then identified by a competitive enzyme-linked immunosorbent assay （ELISA）. Our findings indicated that the VHH would be an alternative tool for haptens mimicry studies.
文摘It is well established that all camelids have unique antibodies circulating in their blood.Unlike antibodies from all other species,these special antibodies are devoid of light chains,and are composed of a heavy chain homodimer.These so-called heavy-chain antibodies(HCAbs)are expressed after a V-D-J rearrangement and require dedicated constant gamma genes. An immune response is raised in these HCAbs following a classical immunization protocol.These HCAbs are easily purified from serum,and their antigen-binding fragment interacts with parts of the target that are less antigenic to conventional antibodies.The antigen binding site of the dromedary HCAb comprises one single domain,referred to as VHH or nanobody(Nb),therefore,a strategy was designed to clone the Nb repertoire of an immunized dromedary and to select the Nb with specificity for our target antigens.The monoclonal Nb is produced well in bacteria,is very stable and highly soluble,and it binds the antigen with high affinity and specificity.Currently,the recombinant Nb has been developed successfully for research purposes, as a probe in biosensors,to diagnose infections,or to treat diseases such as cancer or trypanosomiasis.
基金supported by the National Medical Research Council,Singapore (NMRC COVID19RF2-0002)。
文摘Severe acute respiratory syndrome coronavirus (SARS-CoV-2) is a newly identified member of the coronavirus family that has caused the coronavirus disease 2019 (COVID-19) pandemic. This rapidly evolving and unrelenting SARS-CoV-2has disrupted the lives and livelihoods of millions worldwide. As of 23 August 2021, a total of 211,373,303 COVID-19cases have been confirmed globally with a death toll of 4,424,341. A strong understanding of the infection pathway of SARS-CoV-2, and how our immune system responds to the virus is highly pertinent for guiding the development and improvement of effective treatments. In this review, we discuss the current understanding of neutralising antibodies(NAbs) and their implications in clinical practice. The aspects include the pathophysiology of the immune response,particularly humoral adaptive immunity and the roles of NAbs from B cells in infection clearance. We summarise the onset and persistence of IgA, IgM and IgG antibodies, and we explore their roles in neutralising SARS-CoV-2, their persistence in convalescent individuals, and in reinfection. Furthermore, we also review the applications of neutralising antibodies in the clinical setting—from predictors of disease severity to serological testing to vaccinations, and finally in therapeutics such as convalescent plasma infusion.
基金funded by the Ministry of Science and Higher Education of the Russian Federation(Grant No.075-15-2020-795 of 29.09.2020,unique project ID:RF-190220X0027).
文摘The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At the same time,TP53 is the most frequently mutated gene in human cancers.Mutant p53 proteins lose wild-type p53 tumor suppression functions but acquire new oncogenic properties,among which are deregulating cell proliferation,increasing chemoresistance,disrupting tissue architecture,and promoting migration,invasion and metastasis as well as several other pro-oncogenic activities.The oncogenic p53 mutation Y220C creates an extended surface crevice in the DNA-binding domain destabilizing p53 and causing its denaturation and aggregation.This cavity accommodates stabilizing small molecules that have therapeutic values.The development of suitable small-molecule stabilizers is one of the therapeutic strategies for reactivating the Y220C mutant protein.In this review,we summarize approaches that target p53-Y220C,including reactivating this mutation with small molecules that bind Y220C to the hydrophobic pocket and developing immunotherapies as the goal for the near future,which target tumor cells that express the p53-Y220C neoantigen.
基金Supported by Grants from the National Natural Science Foundation of China, No. 39970340the Scientific Fund of the Chinese Ministry of Health, 98-2-283the Natural Science Foundation of Shanghai,No. 02ZB14041 and 034119916
文摘AIM: To investigate the role of P-selectin, intercellular adhesion molecule-1 (ICAM-1) and dendritic cells (DCs)in liver/kidney of rats with hepatic/renal ischemiareperfusion injury and the preventive effect of anti-Pselectin lectin-EGF domain monoclonal antibody (anti-PsLEGFmAb) on the injury.METHODS: Rat models of hepatic and renal ischemiareperfusion were established. The rats were then divided into two groups, one group treated with anti-PsL-EGFmAb(n = 20) and control treated with saline (n = 20). Both groups were subdivided into four groups according to reperfusion time (1, 3, 6 and 24 h). The sham-operated group (n = 5) served as a control group. DCs were observed by the microscopic image method, while P-selectin and ICAM-1 were analyzed by immunohistochemistry.RESULTS: P-selectin increased significantly in hepatic sinusoidal endothelial cells and renal tubular epithelial cells 1 h after ischemia-reperfusion, and the expression of ICAM-1 was up-regulated in hepatic sinusoid and renal vessels after 6 h. CD1a+CD80+DCs gradually increased in hepatic sinusoidal endothelium and renal tubules and interstitium 1 h after ischemia-reperfusion, and there was the most number of DCs in 24-h group. The localization of DCs was associated with rat hepatic/renal function.These changes became less significant in rats treated with anti-PsL-EGFmAb.CONCLUSION: DCs play an important role in immune pathogenesis of hepatic/renal ischemia-reperfusion injury.Anti-PsL-EGFmAb may regulate and inhibit local DC immigration and accumulation in liver/kidney.
基金Financial support by Department of Biotechnology,Government of India,New Delhi for construction of phage display library and its applications, and Indian Council of Agricultural Research,New Delhi for infrastructure assistance
文摘Objective:To isolate and characterize Staphylococcus aureus(S.aureus)β-hemolysinneutralizing dAbs from phage display library of Indian desert camel.Methods:Phage display library of 5×10 dAb clones of LPS-immunized Indian desert camel constructed in our laboratory was used for selection of S.aureus exotoxin-specific clones by panning technique.Enrichment of Ag-specific clones in successive rounds of panning was assessed by phage-ELISA and phage titration.Different dAb clones binding to S.aureus exotoxin Ags were expressed with C-terminal 6×His tag in E.coli and purified by Ni-chelate chromatography.The expression was verified by SDS-PAGE and western blotting.The purified clones were tested for inhibition of ’hot-cold’ hemolytic activity in vitro.Resistance to thermal inactivation of the dAb clones was studied by observing the effect of heat treatment from 50℃to 99℃for 30 min on the ’hot-cold’ hemolytic activity in vitro.Results:Several dAb clones binding to S.aureus exotoxins were isolated and enriched by three rounds of panning.The soluble dAb clones were approximately～16 kDa in size and reacted with 6×His tag specific murine monoclonal antibody in western blot.One of the Ni-chelate affinity purified dAb.6×His clones,inhibited S.aureusβ-hemolysin activity in vitro and resisted thermal inactivation upto 991.Conclusions:An S.aureusβ-hemolysinneutralizing dAb clone of possible therapeutic potential has been isolated.
基金supported by Important National Science & Technology Specific Projects (2012ZX10004403, 2012ZX10004219)National Natural Scientific Fund of China (81072675)
文摘Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus closely related to the human pathogens including yellow fever virus, dengue virus and West Nile virus. There are currently no effective antiviral therapies for all of the flavivirus and only a few highly effective vaccines are licensed for human use. In this paper, the E protein domain III (DIII) of six heterologous flaviviruses (DENV1-4, WNV and JEV) was expressed in Escherichia coli successfully. The proteins were purified after a solubilization and refolding procedure, characterized by SDS-PAGE and Western blotting. Competitive inhibition showed that all recombinant flavivirus DIII proteins blocked the entry of JEV into BHK-21 cells. Further studies indicated that antibodies induced by the soluble recombinant flavivirus DIII partially protected mice against lethal JEV challenge. These results demonstrated that recombinant flavivirus DIII proteins could inhibit JEV infection competitively, and immunization with proper folding flavivirus DIII induced cross-protection against JEV infection in mice, implying a possible role of DIII for the cross-protection among flavivirus as well as its use in antigens for immunization in animal models.
基金Supported by the 973 key research finance of the state(2002CB 513000-07 ).
文摘Objective To investigate the expression of discoidin domain receptor 2 (DDR2) of fibroblast-like synovial cells in im- proved adjuvant-induced animal (AIA) model for rheumatoid arthritis (RA) and to provide evidence for DDR2’s antagonist use clinically. Methods AIA was modified by administrating 0.1 mL of complete Freund’s adjuvant (CFA, mixed with 5 mg Bacillus Calmette-Guerin vaccine/mL) into rats’ right hind paws and 0.125 mL tumor necrosis factor-α (2 U/mL) into right ankles and subpatellar fatty tissue. The expression of DDR2 in fibroblast-like synovial cells was assessed using immunohistochemistry, immunofluorescence histochemistry, and in situ hybridization methods. Levels of anti-collagen II antibody were measured using enzyme-linked immunosorbent assay. Results Given the terms mentioned above, we found a more practical rat model, apparently decreasing immunization time (average 3-5 days). DDR2 can be detected upon the 15th day of immunization; expression gradually increased with time going on, and reaching a peak 35 days after immunization before gradually decreasing. Serum anti-collagen II antibody showed similar expression patterns as DDR2, but reached peak later than DDR2, about 40 days after immunization. Conclusion Regular expression of DDR2 in animal models infers its important role in the pathological process of RA.
文摘Dendritic cells(DCs) are professinal antigen-presenting cells with the ability to initiate primary Tcell responses. While it iswell known that inflammatory stimuli induce the functional maturation of immature DCs, whether adhesion molecule selectins regulate DCmaturation is poorly understood. Using anti-P-selectin lectin-EGF domain monoclonal antibody (PsL-EGFmAb) that blocks the adhesionof P-, E-, and L-selectin, we demonstrate herein that selectins play important role in stimulating functional maturation of immature DCs.Immature DCs are generated from human cord blood CD34+hematopoietic stem/progenitor cells that were cultured in the presence of stemcell factor, Fms-like tyrosine-kinase-3 ligand, granulocyte-macrophage colony stimulating factor, and transform growth factor-β1. Whenstimulated with tumor necrosis factor-alpha(TNF-α), immature DCs differentiated into mature DCs, producing increased levels of costim-ulatory molecules and interleukin (IL)-12 and obtaining the ability to potently activate naive Tcells. Interestingly, in contrast to matureDCs derived from TNF-α-induced immature DC cultures without PsL-EGFmAb, immature DCs treated with PsL-EGFmAb for7 days werecompletely blocked their maturation, as evidenced by decreased expression of costimulatory molecules CD80, CD86, and CD83, inhibi-ted production of IL-12, and inability to activate naive Tcellsin vitro. Thus, blockade of selectins using PsL-EGFmAb will prove to bea valuable tool for the study of the molecuar mechanisms of DC maturation, as well as for the prevention and treatment of DC-mediated au-toimmunity.
基金the Science and Technology Department of Jilin Province(No 20060563)
文摘This study focuses on the expression of human protein tyrosine phosphatase 1B （PTP1 B） catalytic domain （△PTP1B） and preparation of polyclonal antibody against △PTP1B. △PTP1B gene was PCR amplified with the cDNA of human PTP1B as the template, and cloned into the pT7 expression vector. The recombinant pT7-△PTP1B was expressed in E. eoli Rosetta（ DE3 ） host cells and purified. The antiserum was prepared by immunizing rabhit with purified recombinant △PTP1B. The polyclonal antibody against △PTP1B was purified by PVDF immobilized antigen affinity chromatography. △PTP1B was correctly cloned, expressed, and purified as confirmed by PCR, DNA sequence analysis, SDS-PAGE western blotting, and ILPLC. The titer and sensitivity of the antibody were 1：2500（ volume ratio） and 0. 1 ng, respectively. This study provides an important basis for further studying the biological function of PTP1B and its relationship with human diseases.
基金supported by the National Natural Science Foundation of China,No.30360100,30760234,30860260,81160373,81360458
文摘Single-chain variable domain fragment （scFv） 637 is an antigen-specific scFv of myasthenia gravis. In this study, scFv and human serum albumin genes were conjugated and the fusion pro-tein was expressed in Pichia pastoris. The afifnity of scFv-human serum albumin fusion protein to bind to acetylcholine receptor at the neuromuscular junction of human intercostal muscles was detected by immunolfuorescence staining. The ability of the fusion protein to block myas-thenia gravis patient sera binding to acetylcholine receptors and its stability in healthy serum were measured by competitive ELISA. The results showed that the inhibition rate was 2.0-77.4%, and the stability of fusion protein in static healthy sera was about 3 days. This approach suggests the scFv-human serum albumin is a potential candidate for speciifc immunosuppressive therapy of myasthenia gravis.
基金supported by grants from the National Natural Science Foundation of China (30872198 30972566)
文摘Obejective The domainⅢof dengue virus type 2 envelope was cloned and expressed in Escherichia coli and the inhibited effects of recombinant protein on virus was detected. Methods In this study, the domainⅢ(DⅢ) protein of the dengue virus type-2 (DENV-2) envelope (E) antigen was expressed in Escherichia coli by fusion with a carrier protein. The protein was puriifed using enzymatic cleavage and afifnity puriifcation. Rabbit immunization and antibody detection was carried out. Inhibition of DENV-2 infection was observed by DENV-2 EDⅢprotein and its immunity rabbits serum. Results The recombinant expression DENV-2 EDⅢ protein plasmid was constructed successfully. After isopropyl thiogalactoside induction, a speciifc soluble 29 kD protein was obtained, and the expression product accounted for 68.87%of the total protein of the cell lysate. Western blot demonstrated the reactivity of the recombinant protein with his-tag and DENV (Ⅰ-Ⅳ) monoclonal antibodies. The protein was puriifed using enzymatic cleavage and affinity purification. The purified recombinant EDⅢ protein inhibited the entry of DENV-2 into BHK-21 cells. DENV-2 plaque neutralization assays were carried out using serially diluted antibodies against EDⅢprotein. At a 1︰16 dilution, the antibodies produced at least 90%neutralization of the DENV-2 virus. Furthermore, the antibodies continued to exhibit high neutralization effects (approximately 80%) until the anti-EDⅢantibody titer reached 1︰1 024. Conclusions DENV-2 EDⅢwas cloned and expressed successfully. DENV-2 EDⅢprotein could be useful in the development of inexpensive dengue vaccine. The data also suggested that DENV-2 employed an attachment molecule or receptor for its entry into C6/36 mosquito cells.
基金supported by the National Natural Science Foundation of China,No.30600099(FD)
文摘Screening humanized antibodies from a human Fab phage display library is an effective and quick method to obtain beta-amyloid oligomers. Thus, the present study prepared amyloid-beta 42 oli- gomers and constructed a have human Fab phage display library based on blood samples from six healthy people. After three rounds of biopanning in vitro, a human single-domain antibody that spe- cifically recognized amyloid-beta 42 oligomers was identified. Western blot and enzyme-linked im- munosorbent assay demonstrated this antibody bound specifically to human amyloid-beta 42 tetramer and nonamer, but not the monomer or high molecular weight oligomers. This study suc- cessfully constructed a human phage display library and screened a single-domain antibody that specifically recognized amyloid-beta 42 oligomers.
