Canine atopic dermatitis(CAD)is a prevalent genetically susceptible infammatory and pruritic allergic skin condition afecting not only the health of dogs but also the quality of life of their owners.Interleukin-31(IL-...Canine atopic dermatitis(CAD)is a prevalent genetically susceptible infammatory and pruritic allergic skin condition afecting not only the health of dogs but also the quality of life of their owners.Interleukin-31(IL-31)and interleukin-31 receptor alpha(IL-31RA)are essential for the development of pruritus in primates and mice.Hence,it is expected that inhibiting IL-31RA will be an efective approach to alleviate pruritus.The purpose of the study was to produce anti-canine IL-31RA polyclonal antibodies(anti-IL-31RA pAbs)and evaluate their efcacy in inhibiting house dust mite(HDM)-evoked pruritic responses.Dogs were immunized with antigens formed by IL-31RA recombinant short peptides coupled to BSA to produce anti-IL-31RA pAbs.The CAD model was developed by using HDM allergen stimulation,and the efects of IL-31RA pAbs on the reduction of pruritus in CAD model dogs were examined.The Canine Atopic Dermatitis Extent and Severity Index(CADESI)-4 and pruritus Visual Analog Scale(pVAS)were utilized to evaluate pruritic responses,and skin tissue samples were collected from the inguinal area for pathological assessment of skin infammatory cell infltration.The results showed that anti-IL-31RA pAbs with high titers(1:128,000)and specifcity were efectively produced.In the CAD model group,the severity of skin damage,pruritus score,infammatory cell infltration and level of infammatory factors were considerably elevated.Anti-IL-31RA pAbs relieved pruritic behavior and dermatitis in dogs compared to placebo-treated dogs.In conclusion,anti-IL-31RA pAbs efectively suppressed CAD in vivo and are anticipated to be an efective novel treatment for pruritic skin disorders such as CAD.展开更多
Human African trypanosomiasis (HAT), commonly known as sleeping sickness is one of the neglected tropical diseases (NTDs), which is fatal if left untreated. Its diagnosis is a challenge since the signs and symptoms of...Human African trypanosomiasis (HAT), commonly known as sleeping sickness is one of the neglected tropical diseases (NTDs), which is fatal if left untreated. Its diagnosis is a challenge since the signs and symptoms of the primary phase are not specific, the existing diagnostic methods have low sensitivity and specificity, and the available drugs have some toxicity. New, robust, and cost-effective techniques are needed for the early identification of parasites. This study aimed to assess the sensitivity and specificity of two different types of polyclonal antibodies against T. b. gambiense using antigen detection ELISA. Polyclonal antibodies against the expressed proteins Tbg I2 and Tbg I17 were produced using New Zealand white rabbits. The antibody titer measured was greater than 32 g/L after the 3<sup>rd</sup> immunization for the expressed protein Tbg I2. For the expressed protein Tbg I17, the antibody titer measured was greater than 32 g/L after the 4<sup>th</sup> immunization. The sensitivity and specificity of the Tbg I2 polyclonal antibody confirmed with Polymerase Chain Reaction (PCR) as gold standard were respectively 89.5% and 80.6%, while for the Tbg I17 polyclonal antibody, the sensitivity and specificity were respectively 92.1% and 88.9%. The area under the curve for the Tbg I2 polyclonal antibody was 0.90 ± 0.032, while for the Tbg I17 polyclonal antibody, the area under the curve was 0.92 ± 0.0. The Tbg I17 polyclonal antibody produced in New Zealand white rabbits has good sensitivity and good specificity;it can be successfully used in the diagnosis of HAT.展开更多
[Objective] This study aimed to clone the E. coil NrfA gene and construct the pET-28a (+)-NrfA prokaryotic expression vector for preparation of polyclonal anti- body against E. coil NrfA. [Method] E. coil NrfA gene...[Objective] This study aimed to clone the E. coil NrfA gene and construct the pET-28a (+)-NrfA prokaryotic expression vector for preparation of polyclonal anti- body against E. coil NrfA. [Method] E. coil NrfA gene was cloned from the E. coli genome DNA by PCR and inserted into the vector pET-28a(+) to construct prokary- otic expression vector pET-28a (+)-NrfA. E. coil NrfA protein was expressed by IPTG induction and purified. Polyclonal antibody against NrfA protein was prepared by im- munizing rabbit with routine method. The specificity and titer of polyclonal antibody was confirmed by ELISA and Western Blotting. [Result] The constructed prokaryotic expression vector pET-28a(+)-NrfA was induced by IPTG, the recombinant NrfA pro- tein could be expressed effectively. The titer of rabbit anti-NrfA polyclonal antibody obtained by immunization and purification was about 1:204 900. Western Blotting anal- ysis indicated that the obtained polyclonal antibody against E. coil NrfA protein had high titer and high specificity. [Conclusion] E. coil NrfA gene was cloned and the prokaryotic expression vector pET-28a (+)-NrfA was constructed successfully, poly- clonal antibody with high titer and high specificity was prepared, which laid the foun- dation for the study of NrfA in different strains of bacteria.展开更多
[Objective] This study aimed to conduct prokaryotic expression of rice SDG711 C-terminal and to prepare its polyclonal antibody. [Method] C-terminal of rice SDG711 containing relatively intensive antigen determinants ...[Objective] This study aimed to conduct prokaryotic expression of rice SDG711 C-terminal and to prepare its polyclonal antibody. [Method] C-terminal of rice SDG711 containing relatively intensive antigen determinants was selected for prokaryotic expression, prokaryotic expression vector pET28a-711C was constructed and the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) competent cells. The recombinant fusion protein was induced by IPTG and purified to immunize a New Zealand white rabbit as the antigen, and polyclonal antibody was obtained and confirmed by Western-blot analysis. [Result] The polyclonal anti- body was successfully prepared and could efficiently detect the expressed antigen. [Conclusion] This study laid the foundation for further investigating the functions of SDG711 protein in rice.展开更多
Serum immunoglobulin from the mandarin fish, or the so called Chinese perch, Siniperca chuatsi (Basilewsky), was successfully purified using affinity chromatography. Heavy and light chains were detected on electrophor...Serum immunoglobulin from the mandarin fish, or the so called Chinese perch, Siniperca chuatsi (Basilewsky), was successfully purified using affinity chromatography. Heavy and light chains were detected on electrophoresis gel, with molecular weights being estimated at 72 and 29 kDa, respectively. The tetrameric IgM of S. chuatsi was calculated to be 808 kDa. The rabbit polyclonal antisera against the purifed immunoglobulin were developed and tested by Western blot analysis. The antisera reacted strongly with the heavy chains of S. chuatsi immunoglobulin. Humoral immune responses of the mandarin fish can then be examined using the developed polyclonal antibody.展开更多
Izumol is a novel member of the immunoglobulin superfamily locating on sperm, and is indispensable for sperm-egg fusion. According to its immunoglobulin-like domain in the extracellular region, Izumol was fractionated...Izumol is a novel member of the immunoglobulin superfamily locating on sperm, and is indispensable for sperm-egg fusion. According to its immunoglobulin-like domain in the extracellular region, Izumol was fractionated into 6 fragments (F0-F5) which were ligated with pGEX-4T1 to construct the prokaryotic expression vectors pGEX-Fn. The recombinant plasmids were transformed into Escherichia coli BL21 (DE3) and the GST-Fn fusion proteins were expressed successfully by induction with IPTG. GST-F0, a recombinant fusion protein of GST with the full length of extracellular region of mature cashmere goat Izumol, was purified by polyacrylamide gel slicing method and was used as an antigen to immunize the Kunming mouse to generate anti-GST-Izumol ascetic polyclonal antibody with intraperitoneal injection of S 180 cells. Subsequently, the anti-GST-Izumol polyclonal antibody was purified with miscellaneous antigen by glutaraldehyde cross-linking method. Western blotting analysis showed that the purified ascetic polyclonal antibody had high affinity to all 6 GST-Izumol fragment fusion proteins. Immunohistochemical analysis with this antibody displayed that the cashmere goat Izumol proteins were at the equatorial segment of sperm head surface. These results indicate that this polyclonal antibody has high specificity and lays the foundations for further study on the expression pattern of Izumol in cashmere goat testis and binding abilities of each extra-membrane fragment of Izumol to the egg surface.展开更多
BACKGROUND: Studies have shown that the Repeat superfamily, could be related to neural LRRN3, a member of the Neuron Leucine-Rich development, differentiation, information transmission, and other functions, but most ...BACKGROUND: Studies have shown that the Repeat superfamily, could be related to neural LRRN3, a member of the Neuron Leucine-Rich development, differentiation, information transmission, and other functions, but most studies have focused on nucleic acid levels and few have reported on LRRN3 protein levels. OBJECTIVE: To prepare rabbit anti-rat LRRN3 polyclonal antibody and to observe protein tissue expression profiles. DESIGN, TIME AND SEI-rlNG: In vitro, molecular, biological experiments were performed from October 2007 to April 2009 in Laboratory of Neurobiology at Xiangya School of Medicine, Central South University. MATERIALS: Immunization antigen, namely rat MaI-LRRN3C-His recombinant protein, was provided by the Laboratory of Neurobiology at Xiangya School of Medicine, Central South University. METHODS: Rat Mal-LRRN3C-His recombinant protein was used to immunize male, New Zealand rabbits, and rabbit anti-rat LRRN3 polyclonal antibody was prepared. MAIN OUTCOME MEASURES: Antibody purification was conducted using Protein A affinity chromatography, and the LRRN3 anti-serum titer was identified using enzyme-linked immunosorbent assay. Immunohistochemical techniques and Western blot preliminary tests were used to determine LRRN3 protein expression profiles in adult rats. RESULTS: A highly purified rabbit anti-rat LRRN3 polyclonal antibody was obtained. Western Blot results from rat brain total protein revealed a band at 79 kD, which was consistent with the size of LRRN3. Immunohistochemistry results showed that protein was mainly expressed in the central nervous system, and no significant positive signals were observed in other tissues. Positive cells included neurons of cerebral cortex and hippocampal dentate gyrus granule cell layer, and cerebellar Purkinje cells. There was no positive expression in glial cells. CONCLUSION: Rabbit anti-rat LRRN3 polyclonal antibody was successfully prepared at a high purity from the prokaryotic-expressed MaI-LRRN3C-His recombinant protein, which served as an antigen. Rat LRRN3 protein was primarily expressed in cerebral cortex neurons, hippocampal dentate gyrus granule cell layer neurons, and cerebellar Purkinje cells.展开更多
A competitive enzyme-linked immunosorbent assay (ELISA) suitable for the determination of the urea herbicide isoproturon, 3-(4-isopropylphenyl)-l,l-dimethylurea, in food and environmental samples was developed. Tw...A competitive enzyme-linked immunosorbent assay (ELISA) suitable for the determination of the urea herbicide isoproturon, 3-(4-isopropylphenyl)-l,l-dimethylurea, in food and environmental samples was developed. Two haptens named 1-(3- carboxypropyl)-3-(4-isopropylphenyl)-1-methylurea (hapten 4C) and 1-(5-carboxypentyl)-3-(4-isopropylphenyl)-1- methylurea (hapten 6C) were synthesized. The haptens were coupled to bovine serum albumin (BSA) and ovalbumin (OVA), respectively, using the N-hydroxysuccinimide reaction. The hapten 6C-BSA conjugate was used as the immunogen, with which a high-titer anti-isoproturon polyclonal antibody (pAb) was successfully obtained by immunization of New Zealand white rabbits. The hapten 4C-OVA conjugate was used as coating antigen and a method of the indirect competitive ELISA for isoproturon was established. The haptens were confirmed with TLC, IR, and 1H NMR. The conjugation molar ratios of hapten 4C to OVA and hapten 6C to BSA were 36:1 and 46:1, respectively, as calculated by a UV spectrophotometry. The highest titer of the anti-isoproturon sera determined by a non-competitive indirect ELISA procedure was 1.6 × 10^5. The optimal concentrations of the coating antigen and the dilution of the anti-isoproturon sera used in the ELISA were 0.1 mg·L^-1 and 1.0 × 10^5, respectively. The concentration of isoproturon that inhibits 50% of antibody-antigen binding (IC50) was 0.07 mg·mL^-1. The cross-reactivities of six urea herbicides including chlorbromuron, fluometuron, monolinuron were lower than 0.1%. Isoproturon is a small molecule without immune activity and active functional group for attaching to carrier protein. To produce an antibody against isoproturon with high titer and high specificity is the most important step in the development of an immunochemical method for the determination of isoproturon in food and environmental samples. The two haptens synthesized in this study have carboxyl groups and accommodate different lengths of spacer arms, and the phenyl and isopropyl groups are fully exposed. An anti-isoproturon polyclonal antibody with high titer and high specificity was successfully obtained by immunization of rabbits with the conjugate of the hapten attached to the protein carrier.展开更多
A polyclonal antibody-based antigen-capture ELISA (AC-ELISA) has been developed for detection of Canine parvovirus (CPV) antigens in faecal samples of dogs. The assay uses rabbit anti-CPV polyclonal antibody as th...A polyclonal antibody-based antigen-capture ELISA (AC-ELISA) has been developed for detection of Canine parvovirus (CPV) antigens in faecal samples of dogs. The assay uses rabbit anti-CPV polyclonal antibody as the capture antibody, guinea pig anti-CPV polyclonal antibody as tracing antibody and anti-guinea pig HRPO conjugate as the detection system. The optimum dilution of the capture antibody and the tracing antibody capable of detecting the CPV-2 antigens was found to be 1:1 600 and 1:400, respectively, in the check-board titration. In this study, a total of 152 samples (129 faecal samples and 23 cell culture supernatant) were tested both by AC-ELISA and by polymerase chain reaction (PCR). Of the samples tested, 69 and 78 samples were found positive by AC-ELISA and PCR, respectively. The AC-ELISA had relative sensitivity, relative specificity and accuracy of 88.4%, 100.0% and 91.4% respectively. The analytical sensitivity of AC-ELISA was estimated to be 102.8 TCID50/mL whereas PCR sensitivity was 100.8 TCIDs0/mL. The AC-ELISA is a simple, quick and reliable method for screening large numbers of faecal samples of dogs suspected of CPV infection.展开更多
Aquaporins(AQPs) are specific membrane channels for water and other small nonionic molecules.In order to overcome the difficulties to generate the effictive antibody of membrane protein,we selected the cytoplasmic C...Aquaporins(AQPs) are specific membrane channels for water and other small nonionic molecules.In order to overcome the difficulties to generate the effictive antibody of membrane protein,we selected the cytoplasmic C-terminus of Aquaporin 1(AQP1) as an unique antigen.The long C-terminus of mouse AQP1 was overexpressed in the Glutathione S-tansferase Gene Fusion System.On the basis of the resonable amounts of soluable membrane protein peptides,we prepared the specific antibody.To pursure this object,we constructed pGEX-4T-1/mAQP1(DNA sequence from 700 to 801 bp) recombinant plasmid and transformed it into Escherichia coli BL21 cells.The GST-AQP1 C-terminal hydrophilic peptide fusion protein was induced by IPTG and further purified by Glutathione Sepharose 4B to obtain the right size fusion protein.Then we immunized the New Zealand rabbits to prepare the antiserum.The purified AQP1 antibody showed high sensitivity by ELISA assay and high specificity by Western blot with AQP1 null mice served as negative control.Finally,we also checked the AQP1 localization in the mouse renal tissues in wild type of mice and AQP1 null mice served as negative control.We demonstrated that AQP1 was highly expressed at the descending limb of Henle tube using our purified AQP1 antibody,which was consistent with previous report.The successful design and preparation of AQP1 antibody through GST technique is an example as making antibodies against a specific membrane protein.展开更多
Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism a...Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism and elimination. To further explore the role of PXR in body’s homeostatic mechanisms, we for the first time, report successful prokary- otic expression and purification of full-length PXR and preparation of polyclonal antibody against the whole protein. The full-length cDNA encoding a 434 amino acids protein was sub-cloned into prokaryotic expression vector, pET-30b and transformed into E. coli BL21(DE3) cells for efficient over expression. The inclusion body fraction, containing the expressed recombinant protein, was purified first by solubilizing in sarcosine extraction buffer and then by affinity column chromatography using Ni-NTA His-Bind matrix. The efficacy of anti-PXR antibody was confirmed by immunocytology, Western blot analysis, EMSA and immunohistochemistry. The antibody obtained was capable of detecting human and mouse PXR with high specificity and sensitivity. Immunofluorescence staining of COS-1 cells transfected with human or mouse PXR showed a clear nuclear localization. Results from immunohistochemistry showed that level of PXR in liver sections is immunologically detectable in the nuclei. Similar to exogenously transfected PXR, Western blot analysis of cell extract from HepG2 and COLO320DM cells revealed a major protein band for endogenous PXR having the expected molecular weight of 50 kDa. Relevance of other immunodetectable bands with reference to PXR isoforms and current testimony are evaluated. Advantages of antibody raised against full-length PXR protein for functional characterization of receptor is discussed and its application for clinical purposes is envisaged.展开更多
The objective of this study is to express the carbohydrate recognition domain (CRD) of the asialoglycoprotein receptor (ASGPR) H1 and H2 subunits of Marmota himalayan in vitro, and develop polyclonal antibodies ag...The objective of this study is to express the carbohydrate recognition domain (CRD) of the asialoglycoprotein receptor (ASGPR) H1 and H2 subunits of Marmota himalayan in vitro, and develop polyclonal antibodies against the recombinant proteins. RT-PCR was used to amplify ASGPR CRDH1 and CRDH2 from the liver tissue of Marmota himalayan. The products of amplification were subcloned into prokaryotic expression vector pRSET-B, and expressed in E.coli BL21(DE3)plysS. The recombinant proteins were purified using Ni-NTA spin column. The purified proteins were inoculated into BALB/c mice to develop polyclonal antibodies. The sensitivity and specificity of antibodies were evaluated by enzyme-linked immunosorbent assay (ELISA), Western blotting and immunohistochemical staining (IHC). The polyclonal antibodies showed high sensitivity and specificity against both denaturated and native ASGPR proteins. We successfully amplified and expressed the ASGPR CRDs of Marmota himalayan. The nucleic sequences of ASGPR CRDH1 and CRDH2 of Marmota himalayan have been submitted to Genbank and the sequence ID are DQ 845465 and DQ845466, respectively. The proteins and antibodies prepared can be used for targeting gene therapy in a new animal model-Marrnota himalayan—— for the research of infectious diseases of hepatitis viruses and liver cancer treatment.展开更多
A polyclonal antibody against the currently concerned estrogenic bisphenol compounds was produced according to a new scheme. 4,4-Bis (4-hydroxyphenyl) valeric acid was used to synthesize the complete antigen in which...A polyclonal antibody against the currently concerned estrogenic bisphenol compounds was produced according to a new scheme. 4,4-Bis (4-hydroxyphenyl) valeric acid was used to synthesize the complete antigen in which the characteristic bisphenol structure was exposed to the largest extent. The produced polyclonal antibody showed high specificity and affinity for bisphenol A.展开更多
N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals. With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine ...N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals. With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine the free morphine in urine of abusers. The detection limit was calculated to be 40 ng/mL. Simulated urine samples were analyzed with good recoveries, which showed the feasibility of its application in specific morphine determination in urine of morphine abusers.展开更多
Survivin, a novel member of inhibitor of apoptosis(IAP) protein family, is aberrantly expressed in cancer but undetectable in normal, differentiated adult tissues. The cancer-specific expression of survivin, coupled...Survivin, a novel member of inhibitor of apoptosis(IAP) protein family, is aberrantly expressed in cancer but undetectable in normal, differentiated adult tissues. The cancer-specific expression of survivin, coupled with its importance in inhibiting cell death and in regulating cell division makes it a useful diagnostic marker of cancer and a potential target for cancer treatment. Survivin cDNA amplified from the total RNA of 293 cells through RT-PCR was cloned into prokaryotic expression vector pRSET-B. The recombinant plasmid pRSET-B-Surv was expressed in E.coli BL21, and the relative molecule mass(Mr) of expressed fusion protein was approximately 21000. The recombinant protein was purified through Ni^2+ affinity chromatography column and characterized by SDS-PAGE and Western blot. The purified recombinant protein was then injected into rabbits, and antisurvivin polyclonal antibody with a high titer was obtained.展开更多
The adenovirus E1A proteins are primarily concerned with modulating cellular metabolism to make the cell more susceptible to virus replication. In this study, adenovirus E1A gene was amplified via PCR on the HEK-293 c...The adenovirus E1A proteins are primarily concerned with modulating cellular metabolism to make the cell more susceptible to virus replication. In this study, adenovirus E1A gene was amplified via PCR on the HEK-293 cells genome and cloned into prokaryotic expression vector pRsetB. The recombinant plasmid pRsetB-E1A was expressed in E.coli BL21 and the relative molecular mass(Mr) of expressed fusion protein was approximately 36000. The recombinant protein was purified on a Ni-NIA agarose column and detected by SDS-PAGE and Westem blot. The purified recombinant protein was then injected into rabbits and anti-E1A polyclonal antibody with high titer was obtained.展开更多
The hapten, 3-{ [1-(3-(methyl)phenyloxy)-carbonyl]amino}propanoic acid (HOM), mimicking the analyte metolcarb, was synthesized and verified by mass spectrometry (MS) and 1H-nuclear magnetic resonance spectrome...The hapten, 3-{ [1-(3-(methyl)phenyloxy)-carbonyl]amino}propanoic acid (HOM), mimicking the analyte metolcarb, was synthesized and verified by mass spectrometry (MS) and 1H-nuclear magnetic resonance spectrometry (1H-NMR). Then, HOM was conjugated with the carrier proteins bovine serum albumin (BSA) and ovalbumin (OVA) with stoichiometric amounts of N-hydroxysuccinimide/dicyclohexylcarbodimide (NHS/DCC) using the activated ester method. Polyclonal antibodies were raised against the conjugate of HOM-BSA in rabbits. Antiserum titres were determined by noncompetitive indirect ELISA procedures and the titer of pAb01 reached 1.28 × 10^6. The cross-reactivities of the structurally related Nmethylcarbamate insecticides were 0.0% except for dimethacarb. These results indicate that the antibody pAb01 with strong affinity and high specificity can be used to develop a sensitive and rapid detection protocol for metolcarb residue.展开更多
Phosphatase of regenerating liver 3 ( PRL3 ), which belongs to the superfamily of protein tyrosine phosphatases (PTPs), represents a group of low molecular weight PTPs that participate in tumorigenesis and metasta...Phosphatase of regenerating liver 3 ( PRL3 ), which belongs to the superfamily of protein tyrosine phosphatases (PTPs), represents a group of low molecular weight PTPs that participate in tumorigenesis and metastasis processes. Presented here are the results of cloning, prokaryotic expression, purification, and polyclonal antibody preparation of PRL3. To obtain a specific polyclonal antibody against PRL3, the authors have prepared GST-PRL3 to immunize rabbits and purify an anti-PRL3 polyclonal antibody by negative selection affinity columns. Western blot analysis shows that the anti-PRL3 polyclonal antibody has a specific binding ability with PRL3 protein. The anti-PRL3 polyclonal antibody provides a good tool to further study the function of PRL3.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
Objective To prepare polyclonal antibody of transactivated protein 5 of hepatitis C virus nonstructural 5A (NA5ATP5) and to explore its expression in the liver tissues. Methods In Escherichia coli BL21,the prokaryotic...Objective To prepare polyclonal antibody of transactivated protein 5 of hepatitis C virus nonstructural 5A (NA5ATP5) and to explore its expression in the liver tissues. Methods In Escherichia coli BL21,the prokaryotic expression vector pET32a(+)-NS5ATP5 was induced by isopropyl-β-D-thiogalactoside (IPTG),and it was analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. And the purified protein was used to immunize the rabbit to prepare polyclonal antibody,with which we studied the function of NS5ATP5 by determining the different liver tissues with the streptavidin-perosidase (SP) immunohistochemistry method. Results Recombinant NS5ATP5 (molecular weight:65 kD) and polyclonal antibody were successfully prepared. NS5ATP5 expression in the liver of patients with chronic HCV infection was much higher than that of a normal person,and it was detected mainly in the cytoplasm. Conclusion The findings of the expression difference between HCV patients and normal people led to a novel diagnostic marker to detect HCV infection.展开更多
基金the National Natural Science Foundation of China(Grant No.32072938)。
文摘Canine atopic dermatitis(CAD)is a prevalent genetically susceptible infammatory and pruritic allergic skin condition afecting not only the health of dogs but also the quality of life of their owners.Interleukin-31(IL-31)and interleukin-31 receptor alpha(IL-31RA)are essential for the development of pruritus in primates and mice.Hence,it is expected that inhibiting IL-31RA will be an efective approach to alleviate pruritus.The purpose of the study was to produce anti-canine IL-31RA polyclonal antibodies(anti-IL-31RA pAbs)and evaluate their efcacy in inhibiting house dust mite(HDM)-evoked pruritic responses.Dogs were immunized with antigens formed by IL-31RA recombinant short peptides coupled to BSA to produce anti-IL-31RA pAbs.The CAD model was developed by using HDM allergen stimulation,and the efects of IL-31RA pAbs on the reduction of pruritus in CAD model dogs were examined.The Canine Atopic Dermatitis Extent and Severity Index(CADESI)-4 and pruritus Visual Analog Scale(pVAS)were utilized to evaluate pruritic responses,and skin tissue samples were collected from the inguinal area for pathological assessment of skin infammatory cell infltration.The results showed that anti-IL-31RA pAbs with high titers(1:128,000)and specifcity were efectively produced.In the CAD model group,the severity of skin damage,pruritus score,infammatory cell infltration and level of infammatory factors were considerably elevated.Anti-IL-31RA pAbs relieved pruritic behavior and dermatitis in dogs compared to placebo-treated dogs.In conclusion,anti-IL-31RA pAbs efectively suppressed CAD in vivo and are anticipated to be an efective novel treatment for pruritic skin disorders such as CAD.
文摘Human African trypanosomiasis (HAT), commonly known as sleeping sickness is one of the neglected tropical diseases (NTDs), which is fatal if left untreated. Its diagnosis is a challenge since the signs and symptoms of the primary phase are not specific, the existing diagnostic methods have low sensitivity and specificity, and the available drugs have some toxicity. New, robust, and cost-effective techniques are needed for the early identification of parasites. This study aimed to assess the sensitivity and specificity of two different types of polyclonal antibodies against T. b. gambiense using antigen detection ELISA. Polyclonal antibodies against the expressed proteins Tbg I2 and Tbg I17 were produced using New Zealand white rabbits. The antibody titer measured was greater than 32 g/L after the 3<sup>rd</sup> immunization for the expressed protein Tbg I2. For the expressed protein Tbg I17, the antibody titer measured was greater than 32 g/L after the 4<sup>th</sup> immunization. The sensitivity and specificity of the Tbg I2 polyclonal antibody confirmed with Polymerase Chain Reaction (PCR) as gold standard were respectively 89.5% and 80.6%, while for the Tbg I17 polyclonal antibody, the sensitivity and specificity were respectively 92.1% and 88.9%. The area under the curve for the Tbg I2 polyclonal antibody was 0.90 ± 0.032, while for the Tbg I17 polyclonal antibody, the area under the curve was 0.92 ± 0.0. The Tbg I17 polyclonal antibody produced in New Zealand white rabbits has good sensitivity and good specificity;it can be successfully used in the diagnosis of HAT.
文摘[Objective] This study aimed to clone the E. coil NrfA gene and construct the pET-28a (+)-NrfA prokaryotic expression vector for preparation of polyclonal anti- body against E. coil NrfA. [Method] E. coil NrfA gene was cloned from the E. coli genome DNA by PCR and inserted into the vector pET-28a(+) to construct prokary- otic expression vector pET-28a (+)-NrfA. E. coil NrfA protein was expressed by IPTG induction and purified. Polyclonal antibody against NrfA protein was prepared by im- munizing rabbit with routine method. The specificity and titer of polyclonal antibody was confirmed by ELISA and Western Blotting. [Result] The constructed prokaryotic expression vector pET-28a(+)-NrfA was induced by IPTG, the recombinant NrfA pro- tein could be expressed effectively. The titer of rabbit anti-NrfA polyclonal antibody obtained by immunization and purification was about 1:204 900. Western Blotting anal- ysis indicated that the obtained polyclonal antibody against E. coil NrfA protein had high titer and high specificity. [Conclusion] E. coil NrfA gene was cloned and the prokaryotic expression vector pET-28a (+)-NrfA was constructed successfully, poly- clonal antibody with high titer and high specificity was prepared, which laid the foun- dation for the study of NrfA in different strains of bacteria.
基金Supported by Higher School Science and Technology Innovation Project of Guangdong Province (No.2012KJCX0021)National Natural Science Foundation of China (No.30700052)~~
文摘[Objective] This study aimed to conduct prokaryotic expression of rice SDG711 C-terminal and to prepare its polyclonal antibody. [Method] C-terminal of rice SDG711 containing relatively intensive antigen determinants was selected for prokaryotic expression, prokaryotic expression vector pET28a-711C was constructed and the recombinant plasmid was transformed into Escherichia coli BL21 (DE3) competent cells. The recombinant fusion protein was induced by IPTG and purified to immunize a New Zealand white rabbit as the antigen, and polyclonal antibody was obtained and confirmed by Western-blot analysis. [Result] The polyclonal anti- body was successfully prepared and could efficiently detect the expressed antigen. [Conclusion] This study laid the foundation for further investigating the functions of SDG711 protein in rice.
文摘Serum immunoglobulin from the mandarin fish, or the so called Chinese perch, Siniperca chuatsi (Basilewsky), was successfully purified using affinity chromatography. Heavy and light chains were detected on electrophoresis gel, with molecular weights being estimated at 72 and 29 kDa, respectively. The tetrameric IgM of S. chuatsi was calculated to be 808 kDa. The rabbit polyclonal antisera against the purifed immunoglobulin were developed and tested by Western blot analysis. The antisera reacted strongly with the heavy chains of S. chuatsi immunoglobulin. Humoral immune responses of the mandarin fish can then be examined using the developed polyclonal antibody.
基金supported by the Natural Science Foun-dation of Inner Mongolia Autonomous Region, China(20080404MS0505)the National Training Foun-dation for Talents of Basic Sciences, China (J0730648)
文摘Izumol is a novel member of the immunoglobulin superfamily locating on sperm, and is indispensable for sperm-egg fusion. According to its immunoglobulin-like domain in the extracellular region, Izumol was fractionated into 6 fragments (F0-F5) which were ligated with pGEX-4T1 to construct the prokaryotic expression vectors pGEX-Fn. The recombinant plasmids were transformed into Escherichia coli BL21 (DE3) and the GST-Fn fusion proteins were expressed successfully by induction with IPTG. GST-F0, a recombinant fusion protein of GST with the full length of extracellular region of mature cashmere goat Izumol, was purified by polyacrylamide gel slicing method and was used as an antigen to immunize the Kunming mouse to generate anti-GST-Izumol ascetic polyclonal antibody with intraperitoneal injection of S 180 cells. Subsequently, the anti-GST-Izumol polyclonal antibody was purified with miscellaneous antigen by glutaraldehyde cross-linking method. Western blotting analysis showed that the purified ascetic polyclonal antibody had high affinity to all 6 GST-Izumol fragment fusion proteins. Immunohistochemical analysis with this antibody displayed that the cashmere goat Izumol proteins were at the equatorial segment of sperm head surface. These results indicate that this polyclonal antibody has high specificity and lays the foundations for further study on the expression pattern of Izumol in cashmere goat testis and binding abilities of each extra-membrane fragment of Izumol to the egg surface.
基金the National Natural Science Foundation of China,No.30600224,30700438,30600636No.39 Grant by China Postdoctoral Science Foundation,No.20060390886
文摘BACKGROUND: Studies have shown that the Repeat superfamily, could be related to neural LRRN3, a member of the Neuron Leucine-Rich development, differentiation, information transmission, and other functions, but most studies have focused on nucleic acid levels and few have reported on LRRN3 protein levels. OBJECTIVE: To prepare rabbit anti-rat LRRN3 polyclonal antibody and to observe protein tissue expression profiles. DESIGN, TIME AND SEI-rlNG: In vitro, molecular, biological experiments were performed from October 2007 to April 2009 in Laboratory of Neurobiology at Xiangya School of Medicine, Central South University. MATERIALS: Immunization antigen, namely rat MaI-LRRN3C-His recombinant protein, was provided by the Laboratory of Neurobiology at Xiangya School of Medicine, Central South University. METHODS: Rat Mal-LRRN3C-His recombinant protein was used to immunize male, New Zealand rabbits, and rabbit anti-rat LRRN3 polyclonal antibody was prepared. MAIN OUTCOME MEASURES: Antibody purification was conducted using Protein A affinity chromatography, and the LRRN3 anti-serum titer was identified using enzyme-linked immunosorbent assay. Immunohistochemical techniques and Western blot preliminary tests were used to determine LRRN3 protein expression profiles in adult rats. RESULTS: A highly purified rabbit anti-rat LRRN3 polyclonal antibody was obtained. Western Blot results from rat brain total protein revealed a band at 79 kD, which was consistent with the size of LRRN3. Immunohistochemistry results showed that protein was mainly expressed in the central nervous system, and no significant positive signals were observed in other tissues. Positive cells included neurons of cerebral cortex and hippocampal dentate gyrus granule cell layer, and cerebellar Purkinje cells. There was no positive expression in glial cells. CONCLUSION: Rabbit anti-rat LRRN3 polyclonal antibody was successfully prepared at a high purity from the prokaryotic-expressed MaI-LRRN3C-His recombinant protein, which served as an antigen. Rat LRRN3 protein was primarily expressed in cerebral cortex neurons, hippocampal dentate gyrus granule cell layer neurons, and cerebellar Purkinje cells.
基金This work was financially supported by National Natural Science Foundation of China (20447003).
文摘A competitive enzyme-linked immunosorbent assay (ELISA) suitable for the determination of the urea herbicide isoproturon, 3-(4-isopropylphenyl)-l,l-dimethylurea, in food and environmental samples was developed. Two haptens named 1-(3- carboxypropyl)-3-(4-isopropylphenyl)-1-methylurea (hapten 4C) and 1-(5-carboxypentyl)-3-(4-isopropylphenyl)-1- methylurea (hapten 6C) were synthesized. The haptens were coupled to bovine serum albumin (BSA) and ovalbumin (OVA), respectively, using the N-hydroxysuccinimide reaction. The hapten 6C-BSA conjugate was used as the immunogen, with which a high-titer anti-isoproturon polyclonal antibody (pAb) was successfully obtained by immunization of New Zealand white rabbits. The hapten 4C-OVA conjugate was used as coating antigen and a method of the indirect competitive ELISA for isoproturon was established. The haptens were confirmed with TLC, IR, and 1H NMR. The conjugation molar ratios of hapten 4C to OVA and hapten 6C to BSA were 36:1 and 46:1, respectively, as calculated by a UV spectrophotometry. The highest titer of the anti-isoproturon sera determined by a non-competitive indirect ELISA procedure was 1.6 × 10^5. The optimal concentrations of the coating antigen and the dilution of the anti-isoproturon sera used in the ELISA were 0.1 mg·L^-1 and 1.0 × 10^5, respectively. The concentration of isoproturon that inhibits 50% of antibody-antigen binding (IC50) was 0.07 mg·mL^-1. The cross-reactivities of six urea herbicides including chlorbromuron, fluometuron, monolinuron were lower than 0.1%. Isoproturon is a small molecule without immune activity and active functional group for attaching to carrier protein. To produce an antibody against isoproturon with high titer and high specificity is the most important step in the development of an immunochemical method for the determination of isoproturon in food and environmental samples. The two haptens synthesized in this study have carboxyl groups and accommodate different lengths of spacer arms, and the phenyl and isopropyl groups are fully exposed. An anti-isoproturon polyclonal antibody with high titer and high specificity was successfully obtained by immunization of rabbits with the conjugate of the hapten attached to the protein carrier.
文摘A polyclonal antibody-based antigen-capture ELISA (AC-ELISA) has been developed for detection of Canine parvovirus (CPV) antigens in faecal samples of dogs. The assay uses rabbit anti-CPV polyclonal antibody as the capture antibody, guinea pig anti-CPV polyclonal antibody as tracing antibody and anti-guinea pig HRPO conjugate as the detection system. The optimum dilution of the capture antibody and the tracing antibody capable of detecting the CPV-2 antigens was found to be 1:1 600 and 1:400, respectively, in the check-board titration. In this study, a total of 152 samples (129 faecal samples and 23 cell culture supernatant) were tested both by AC-ELISA and by polymerase chain reaction (PCR). Of the samples tested, 69 and 78 samples were found positive by AC-ELISA and PCR, respectively. The AC-ELISA had relative sensitivity, relative specificity and accuracy of 88.4%, 100.0% and 91.4% respectively. The analytical sensitivity of AC-ELISA was estimated to be 102.8 TCID50/mL whereas PCR sensitivity was 100.8 TCIDs0/mL. The AC-ELISA is a simple, quick and reliable method for screening large numbers of faecal samples of dogs suspected of CPV infection.
基金Supported by the National Natural Science Foundation of China(Nos.30700827 and 30871301)Jilin Provincial Science & Technology Department of China(Nos.20070719 and 20080731)Northeast Normal University,China(Nos.20070401,NENU-STC07005)
文摘Aquaporins(AQPs) are specific membrane channels for water and other small nonionic molecules.In order to overcome the difficulties to generate the effictive antibody of membrane protein,we selected the cytoplasmic C-terminus of Aquaporin 1(AQP1) as an unique antigen.The long C-terminus of mouse AQP1 was overexpressed in the Glutathione S-tansferase Gene Fusion System.On the basis of the resonable amounts of soluable membrane protein peptides,we prepared the specific antibody.To pursure this object,we constructed pGEX-4T-1/mAQP1(DNA sequence from 700 to 801 bp) recombinant plasmid and transformed it into Escherichia coli BL21 cells.The GST-AQP1 C-terminal hydrophilic peptide fusion protein was induced by IPTG and further purified by Glutathione Sepharose 4B to obtain the right size fusion protein.Then we immunized the New Zealand rabbits to prepare the antiserum.The purified AQP1 antibody showed high sensitivity by ELISA assay and high specificity by Western blot with AQP1 null mice served as negative control.Finally,we also checked the AQP1 localization in the mouse renal tissues in wild type of mice and AQP1 null mice served as negative control.We demonstrated that AQP1 was highly expressed at the descending limb of Henle tube using our purified AQP1 antibody,which was consistent with previous report.The successful design and preparation of AQP1 antibody through GST technique is an example as making antibodies against a specific membrane protein.
文摘Pregnane and Xenobiotic Receptor (PXR; or Steroid and Xenobiotic Receptor, SXR), a new member of the nuclear receptor superfamily, is thought to modulate a network of genes that are involved in xenobiotic metabolism and elimination. To further explore the role of PXR in body’s homeostatic mechanisms, we for the first time, report successful prokary- otic expression and purification of full-length PXR and preparation of polyclonal antibody against the whole protein. The full-length cDNA encoding a 434 amino acids protein was sub-cloned into prokaryotic expression vector, pET-30b and transformed into E. coli BL21(DE3) cells for efficient over expression. The inclusion body fraction, containing the expressed recombinant protein, was purified first by solubilizing in sarcosine extraction buffer and then by affinity column chromatography using Ni-NTA His-Bind matrix. The efficacy of anti-PXR antibody was confirmed by immunocytology, Western blot analysis, EMSA and immunohistochemistry. The antibody obtained was capable of detecting human and mouse PXR with high specificity and sensitivity. Immunofluorescence staining of COS-1 cells transfected with human or mouse PXR showed a clear nuclear localization. Results from immunohistochemistry showed that level of PXR in liver sections is immunologically detectable in the nuclei. Similar to exogenously transfected PXR, Western blot analysis of cell extract from HepG2 and COLO320DM cells revealed a major protein band for endogenous PXR having the expected molecular weight of 50 kDa. Relevance of other immunodetectable bands with reference to PXR isoforms and current testimony are evaluated. Advantages of antibody raised against full-length PXR protein for functional characterization of receptor is discussed and its application for clinical purposes is envisaged.
基金This project was supported by grants from National Natural Sciences Foundation of China (No 30571646)the Na-tional Basic Research Program (Program 973, No 2005CB522901)
文摘The objective of this study is to express the carbohydrate recognition domain (CRD) of the asialoglycoprotein receptor (ASGPR) H1 and H2 subunits of Marmota himalayan in vitro, and develop polyclonal antibodies against the recombinant proteins. RT-PCR was used to amplify ASGPR CRDH1 and CRDH2 from the liver tissue of Marmota himalayan. The products of amplification were subcloned into prokaryotic expression vector pRSET-B, and expressed in E.coli BL21(DE3)plysS. The recombinant proteins were purified using Ni-NTA spin column. The purified proteins were inoculated into BALB/c mice to develop polyclonal antibodies. The sensitivity and specificity of antibodies were evaluated by enzyme-linked immunosorbent assay (ELISA), Western blotting and immunohistochemical staining (IHC). The polyclonal antibodies showed high sensitivity and specificity against both denaturated and native ASGPR proteins. We successfully amplified and expressed the ASGPR CRDs of Marmota himalayan. The nucleic sequences of ASGPR CRDH1 and CRDH2 of Marmota himalayan have been submitted to Genbank and the sequence ID are DQ 845465 and DQ845466, respectively. The proteins and antibodies prepared can be used for targeting gene therapy in a new animal model-Marrnota himalayan—— for the research of infectious diseases of hepatitis viruses and liver cancer treatment.
基金This work was financially supported by the National Natural Science Foundation of China(Grant No.20075001).
文摘A polyclonal antibody against the currently concerned estrogenic bisphenol compounds was produced according to a new scheme. 4,4-Bis (4-hydroxyphenyl) valeric acid was used to synthesize the complete antigen in which the characteristic bisphenol structure was exposed to the largest extent. The produced polyclonal antibody showed high specificity and affinity for bisphenol A.
文摘N-Conjugated antigen was synthesized and polyclonal antibody with high specificity was obtained from immunizing animals. With this polyclonal antibody, a rapid and efficient CEIA-LIF method was developed to determine the free morphine in urine of abusers. The detection limit was calculated to be 40 ng/mL. Simulated urine samples were analyzed with good recoveries, which showed the feasibility of its application in specific morphine determination in urine of morphine abusers.
文摘Survivin, a novel member of inhibitor of apoptosis(IAP) protein family, is aberrantly expressed in cancer but undetectable in normal, differentiated adult tissues. The cancer-specific expression of survivin, coupled with its importance in inhibiting cell death and in regulating cell division makes it a useful diagnostic marker of cancer and a potential target for cancer treatment. Survivin cDNA amplified from the total RNA of 293 cells through RT-PCR was cloned into prokaryotic expression vector pRSET-B. The recombinant plasmid pRSET-B-Surv was expressed in E.coli BL21, and the relative molecule mass(Mr) of expressed fusion protein was approximately 21000. The recombinant protein was purified through Ni^2+ affinity chromatography column and characterized by SDS-PAGE and Western blot. The purified recombinant protein was then injected into rabbits, and antisurvivin polyclonal antibody with a high titer was obtained.
文摘The adenovirus E1A proteins are primarily concerned with modulating cellular metabolism to make the cell more susceptible to virus replication. In this study, adenovirus E1A gene was amplified via PCR on the HEK-293 cells genome and cloned into prokaryotic expression vector pRsetB. The recombinant plasmid pRsetB-E1A was expressed in E.coli BL21 and the relative molecular mass(Mr) of expressed fusion protein was approximately 36000. The recombinant protein was purified on a Ni-NIA agarose column and detected by SDS-PAGE and Westem blot. The purified recombinant protein was then injected into rabbits and anti-E1A polyclonal antibody with high titer was obtained.
文摘The hapten, 3-{ [1-(3-(methyl)phenyloxy)-carbonyl]amino}propanoic acid (HOM), mimicking the analyte metolcarb, was synthesized and verified by mass spectrometry (MS) and 1H-nuclear magnetic resonance spectrometry (1H-NMR). Then, HOM was conjugated with the carrier proteins bovine serum albumin (BSA) and ovalbumin (OVA) with stoichiometric amounts of N-hydroxysuccinimide/dicyclohexylcarbodimide (NHS/DCC) using the activated ester method. Polyclonal antibodies were raised against the conjugate of HOM-BSA in rabbits. Antiserum titres were determined by noncompetitive indirect ELISA procedures and the titer of pAb01 reached 1.28 × 10^6. The cross-reactivities of the structurally related Nmethylcarbamate insecticides were 0.0% except for dimethacarb. These results indicate that the antibody pAb01 with strong affinity and high specificity can be used to develop a sensitive and rapid detection protocol for metolcarb residue.
基金Supported by National Natural Science Foundation of China(No.30470391).
文摘Phosphatase of regenerating liver 3 ( PRL3 ), which belongs to the superfamily of protein tyrosine phosphatases (PTPs), represents a group of low molecular weight PTPs that participate in tumorigenesis and metastasis processes. Presented here are the results of cloning, prokaryotic expression, purification, and polyclonal antibody preparation of PRL3. To obtain a specific polyclonal antibody against PRL3, the authors have prepared GST-PRL3 to immunize rabbits and purify an anti-PRL3 polyclonal antibody by negative selection affinity columns. Western blot analysis shows that the anti-PRL3 polyclonal antibody has a specific binding ability with PRL3 protein. The anti-PRL3 polyclonal antibody provides a good tool to further study the function of PRL3.
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.C03011402and30371288)
文摘Objective To prepare polyclonal antibody of transactivated protein 5 of hepatitis C virus nonstructural 5A (NA5ATP5) and to explore its expression in the liver tissues. Methods In Escherichia coli BL21,the prokaryotic expression vector pET32a(+)-NS5ATP5 was induced by isopropyl-β-D-thiogalactoside (IPTG),and it was analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and Western blotting. And the purified protein was used to immunize the rabbit to prepare polyclonal antibody,with which we studied the function of NS5ATP5 by determining the different liver tissues with the streptavidin-perosidase (SP) immunohistochemistry method. Results Recombinant NS5ATP5 (molecular weight:65 kD) and polyclonal antibody were successfully prepared. NS5ATP5 expression in the liver of patients with chronic HCV infection was much higher than that of a normal person,and it was detected mainly in the cytoplasm. Conclusion The findings of the expression difference between HCV patients and normal people led to a novel diagnostic marker to detect HCV infection.