Conductive single-wall carbon nanotubes/extracellular matrix hybrid hydrogels promote the lineage-specific development of seeding cells for tissue repair through reconstructing an integrin-dependent niche.

BACKGROUND: The niche of tissue development in vivo involves the growth matrix, biophysical cues and cell-cell interactions. Although natural extracellular matrixes may provide good supporting for seeding cells in vitro, it is evitable to destroy biophysical cues during decellularization. Reconstructing the bioactivities of extracellular matrix-based scaffolds is essential for their usage in tissue repair. RESULTS: In the study, a hybrid hydrogel was developed by incorporating single-wall carbon nanotubes (SWCNTs) into heart-derived extracellular matrixes. Interestingly, insoluble SWCNTs were well dispersed in hybrid hydrogel solution via the interaction with extracellular matrix proteins. Importantly, an augmented integrin-dependent niche was reconstructed in the hybrid hydrogel, which could work like biophysical cues to activate integrin-related pathway of seeding cells. As supporting scaffolds in vitro, the hybrid hydrogels were observed to significantly promote seeding cell adhesion, differentiation, as well as structural and functional development towards mature cardiac tissues. As injectable carrier scaffolds in vivo, the hybrid hydrogels were then used to delivery stem cells for myocardial repair in rats. Similarly, significantly enhanced cardiac differentiation and maturation(12.5 ± 2.3% VS 32.8 ± 5%) of stem cells were detected in vivo, resulting in improved myocardial regeneration and repair. CONCLUSIONS: The study represented a simple and powerful approach for exploring bioactive scaffold to promote stem cell-based tissue repair.

Hepatitis C Virus Genotype Analyses in Chronic Hepatitis C Patients and Individuals With Spontaneous Virus Clearance Using a Newly Developed Serotyping Assay.

BACKGROUND: We developed a novel HCV serotyping assay and detected the genotypes in chronic hepatitis C (CHC) patients and individuals with spontaneous viral clearance (SVC). METHODS: Nine hundred and ninety-seven patients were enrolled in a previous study; their samples were genotyped originally using the molecular assays. Among them, 190 patients achieved sustained virological response; the post-treatment samples were also serotyped. Moreover, 326 samples from follow-up cohorts were serotyped, among whom 66 were from SVC individuals, and 260 from CHC patients. RESULTS: Nine hundred and fifty-eight out of 997 samples were available for serotyping, among which 29 samples generated indeterminate serotyping results. The consistency between the genotyping and serotyping assays was 91.50% (850/929). The specificity and sensitivity were 98.45% and 88.77% for genotype 1, 96.42% and 93.97% for genotype 2, and 94.15% and 80.52% for non-genotype 1 or 2. However, only 41 of 60 genotype-6 samples were correctly serotyped. Little difference was found in the 190 paired serotyping results. No difference existed in the genotype distribution between the SVC and CHC groups (P = 0.08). CONCLUSIONS: The assay provides an accurate alternative for determining HCV genotypes, whereas it is not recommended for detecting genotype 6. Furthermore, it facilitates identifying the genotypes in SVC individuals. HCV genotype has little impact on SVC.

Vitronectin: a promising breast cancer serum biomarker for early diagnosis of breast cancer in patients.

Breast cancer is the most common cancer in women worldwide, identification of new biomarkers for early diagnosis and detection will improve the clinical outcome of breast cancer patients. In the present study, we determined serum levels of vitronectin (VN) in 93 breast cancer patients, 30 benign breast lesions, 9 precancerous lesions, and 30 healthy individuals by enzyme-linked immunosorbent assays. Serum VN level was significantly higher in patients with stage 0-I primary breast cancer than in healthy individuals, patients with benign breast lesion or precancerous lesions, as well as those with breast cancer of higher stages. Serum VN level was significantly and negatively correlated with tumor size, lymph node status, and clinical stage (p < 0.05 in all cases). In addition, VN displayed higher area under curve (AUC) value (0.73, 95 % confidence interval (CI) [0.62-0.84]) than carcinoembryonic antigen (CEA) (0.64, 95 % CI [0.52-0.77]) and cancer antigen 15-3 (CA 15-3) (0.69, 95 % CI [0.58-0.81]) when used to distinguish stage 0-I cancer and normal control. Importantly, the combined use of three biomarkers yielded an improvement in receiver operating characteristic curve with an AUC of 0.83, 95 % CI [0.74-0.92]. Taken together, our current study showed for the first time that serum VN is a promising biomarker for early diagnosis of breast cancer when combined with CEA and CA15-3.

Non-invasive detection of hepatocellular carcinoma serum metabolic profile through surface-enhanced Raman spectroscopy.

The present study aims to identify distinctive Raman spectrum metabolic peaks to predict hepatocellular carcinoma (HCC). We performed a label-free, non-invasive surface-enhanced Raman spectroscopy (SERS) test on 230 serum samples including 47 HCC, 60 normal controls (NC), 68 breast cancer (BC) and 55 lung cancer (LC) by mixing Au@AgNRs with serum directly. Based on the observed SERS spectra, discriminative metabolites including tryptophan, phenylalanine, and etc. were found in HCC, when compared with BC, LC, and NC (P<0.05 in all). Common metabolites-proline, valine, adenine and thymine were found in HCC, BC and LC with compared to NC group (P<0.05). Importantly, Raman spectra of HCC serum biomarker AFP were firstly detected to analyze the HCC prominent peak. Orthogonal partial least squares discriminant analysis was adopted to assess the diagnostic accuracy; area under curve value of HCC is 0.991. This study provides new insights into the HCC metabolites detection through Raman spectroscopy.

IgG, IgM and IgA antibodies against the novel polyprotein in active tuberculosis.

BACKGROUND: The present study was aimed to evaluate whether IgG, IgM and IgA antibodies levels detected against a novel Mycobacterium tuberculosis polyprotein 38 F-64 F (with 38 F being the abbreviation for 38kD-ESAT6-CFP10 and 64 F for Mtb8.4-MPT64-TB16.3-Mtb8) are suitable for diagnosing active tuberculosis, and for monitoring the efficacy of chemotherapy on TB patients. METHODS: In this study, a total of 371 active TB patients without treatment were selected and categorized into S+/C+group (n=143), S-/C+group (n=106) or S-/C- group (n=122). A series of serum samples were collected from 82 active TB patients who had undergone anti-TB chemotherapy for 0-6 months at one month interval. Humoral responses (IgG, IgM and IgA) were determined for the novel Mycobacterium tuberculosis polyprotein using indirect ELISA methods in all of serum samples. RESULTS: For S+/C+, S-/C+and S-/C- active tuberculosis patients before anti-TB chemotherapy, the sensitivities of tests based on IgG were 65.7%, 46.2% and 52.5% respectively; the sensitivities based on IgM were 21.7%, 24.5% and 18.9%; and the sensitivities based on IgA were 25.2%, 17.9% and 23.8%. By combination of three isotypes, for all active tuberculosis patients, the test sensitivity increased to 70.4% with the specificity being 91.5%. After anti-TB chemotherapy, there were no significant differences between groups with different courses of anti-TB chemotherapy. CONCLUSIONS: The novel Mycobacterium tuberculosis polyprotein 38 F-64 F represents potential antigen suitable for measuring IgG, IgM and IgA antibodies. However, the serodiagnostic test based on the 38 F-64 F polyprotein appears unsuitable for monitoring the efficacy of chemotherapy.

Use of immuno-dominant epitope derived from genotype 4 as a diagnostic reagent for detecting the antibodies against Hepatitis E Virus.

BACKGROUND: Despite the genotype 4 has become the dominant cause of hepatitis E disease in China, none antigen derived from genotype 4 of hepatitis E virus (HEV) was used in current commercial anti-HEV immunoassay, and the serological reactivity of antigen derive from genotype 4 is not well-charactered. METHODS: We expressed and purified the 4 main immuno-dominant epitopes derived from genotype 1 and 4 including ORF2 (410-621aa) of genotype 4, ORF3 (47-114aa) of genotype 4, ORF2 (396-606aa) of genotype 1 and ORF3 (56-123aa) of genotype 4. RESULTS: The ORF2 of genotype 4 displayed good diagnostics performance according to ROC analysis using in-house panel, and the immunoassays based the ORF2 of genotype 4 was then developed to detect the anti-HEV IgG antibodies and evaluated further in 530 anti-HEV IgG positive specimens and 380 negative specimens. The sensitivity and the specificity is 98.1% (520/530) and 94.7% (360/380) for immunoassay based on ORF2 of genotype 4, 96.6% (512/530) and 92.6% (352/380) for commercial immunoassay based on genotype 1. It is noted that all of the positive samples will be detected by combing two assays together. The anti-HEV immunoassays based on genotype 4 are in accordance with Chinese anti-HEV national standard,and show an good agreement of 95.8% with commercial assay (kappa=0.913, P=0.014). CONCLUSIONS: The immunoassay based on ORF2G4 displays good performance, and combining assay based on genotype 1 together with genotype 4 will benefit the HEV diagnosis in large scale samples.

A multiple-antigen detection assay for tuberculosis diagnosis based on broadly reactive polyclonal antibodies.

OBJECTIVES: Detection of circulating Mycobacterium tuberculosis (M. tuberculosis) antigens is promising in Tuberculosis (TB) diagnosis. However, not a single antigen marker has been found to be widely expressed in all TB patients. This study is aimed to prepare broadly reactive polyclonal antibodies targeting multiple antigen markers (multi-target antibodies) and evaluate their efficacies in TB diagnosis. MATERIALS AND METHODS: A fusion gene consisting of 38kD, ESAT6, and CFP10 was constructed and overexpressed. The fusion polyprotein was used as an immunogen to elicit production of multi-target antibodies. Their reactivities were tested. Then, the multi-target antibodies and three corresponding antibodies elicited by each single antigen (mono-target antibodies) were evaluated with sandwich ELISA for detecting M. tuberculosis antigens. Their diagnostic efficacies for TB were also compared. RESULTS: The polyprotein successfully elicited production of multi-target antibodies targeting 38kD, ESAT6, and CFP10 as analyzed by Western blotting. When used as coating antibodies, the multi-target antibodies were more efficient in capturing the three antigens than the corresponding mono-target antibodies. By testing clinical serum, the multi-target antibodies demonstrated significantly higher sensitivity for clinical TB diagnosis than all three mono-target antibodies. CONCLUSION: The multi-target antibodies allowed detecting multiple antigens simultaneously and significantly enhanced TB detection compared to routine mono-target antibodies. Our study may provide a promising strategy for TB diagnosis.

Protein microarray-mediated detection of antienterovirus antibodies in serum.

OBJECTIVE: To utilize prokaryotic gene expression and protein microarray to develop and evaluate a sensitive, accurate protein microarray assay for detecting antienterovirus antibodies in serum samples from patients with hand, foot and mouth disease (HFMD). Enterovirus 71 (EV71) and coxsackievirus A16 (CA16), two common causative agents for HFMD, were used for assay development. METHODS: Serum was collected from patients with HFMD and healthy controls. EV71 and CA16 VP1 and VP3 genes were expressed in transfected Escherichia coli; the resultant VP1 and 3 proteins were used in a microarray assay for human serum EV71 and CA16 immunoglobulin (Ig) M and IgG. To validate the microarray assay, serum samples were tested for EV71 IgM using enzyme-linked immunosorbent assay (ELISA). RESULTS: Out of 50 patients with HFMD, EV71 IgM and CA16 IgM was detected in 80% and 44% of serum samples, respectively, using protein microarray, and EV71 IgM was detected in 78% of samples using ELISA. Protein microarray and ELISA showed 100% specificity for EV71-IgM detection. CONCLUSION: The protein microarray assay developed in the present study shows potential as a sensitive technique for detecting EV71 IgM in serum samples from patients with HFMD.

A novel and simple preparative method for uniform-sized PLGA microspheres: Preliminary application in antitubercular drug delivery.

Particle size has been demonstrated as a key parameter influencing the phagocytosis of drug-loaded PLGA microspheres (MS) by the target cells. However, the current preparative methods were either insufficient in controlling the homogeneity of the produced MS, or requires sophisticated and costly equipment. This study aimed to explore a simple and economical method for uniform PLGA MS preparation. Based on the heterogeneous emulsification of routine mechanical stirring, we designed an adjuvant strategy to enhance the homogeneity of MS. By using glass beads as adjutant, the dispersion produced during mechanical stirring was much more homogeneous in the solution. The particles produced were much smaller and the size distribution was much narrower as compared with those produced using the routine mechanical stirring method under the same condition. After enrichment by selective centrifugation, about 60% of the particles of similar size were obtained, providing further evidence for the efficiency of the novel method in controlling particle homogeneity. Further, the method was applied to prepare rifampicin-loaded PLGA MS of the optimized size for macrophage uptake. The functional evaluation showed that the prepared PLGA MS could efficiently deliver an antitubercular drug into macrophages and maintain a higher intracellular concentration by controlled release, suggesting the potential application of the method in PLGA MS-based drug delivery. Collectively, the study provided a simple and economical method for preparing uniform-sized PLGA MS with potential of widespread applications.

Identification of Novel RD1 Antigens and Their Combinations for Diagnosis of Sputum Smear-/Culture+ TB Patients.

Rapid and accurate diagnosis of pulmonary tuberculosis (PTB) is an unresolved problem worldwide, especially for sputum smear- (S-) cases. In this study, five antigen genes including Rv3871, Rv3874, Rv3875, Rv3876, and Rv3879 were cloned from Mycobacterium tuberculosis (Mtb) RD1 and overexpressed to generate antigen fragments. These antigens and their combinations were investigated for PTB serodiagnosis. 298 serum samples were collected from active PTB patients, including 117 sputum smear+ (S+) and sputum culture+ (C+) cases, 101 S-/C+ cases, and 80 S-/C- cases. The serum IgG levels of the five antigens were measured by ELISA. Based on IgG levels, the sensitivity/specificity of Rv3871, Rv3874, Rv3875, Rv3876, and Rv3879 for PTB detection was 81.21%/74.74%, 63.09%/94.78%, 32.21%/87.37%, 62.42%/85.26%, and 83.56%/83.16%, respectively. Furthermore, the optimal result for PTB diagnosis was achieved by combining antigens Rv3871, Rv3876, and Rv3879. In addition, the IgG levels of Rv3871, Rv3876, and Rv3879 were found to be higher in S-/C+ PTB patients than in other PTB populations. More importantly, combination of the three antigens demonstrated superior diagnostic performance for both S-/C+ and S-/C- PTB. In conclusion, the combination of Rv3871, Rv3876, and Rv3879 induced higher IgG response in sputum S-/C+ PTB patients and represents a promising biomarker combination for diagnosing of PTB.

Anti-hMAM monoclonal antibodies evaluated in breast and non-breast tissues for differential diagnosis implication.

PURPOSE: Human mammaglobin (hMAM) is a breast tissue-specific marker that may have potency for the diagnosis of breast cancer. However, there is a lack of commercialization of anti-hMAM antibody made in China. METHODS: Immunoreactivities of 2 self-made monoclonal anti-hMAM antibodies, MEF521 and MDA822, were evaluated by immunohistochemistry staining and compared with imported monoclonal antibody ab81611. A total of 48 cases of primary breast cancers, 36 cases of benign or normal breast tissues, 52 cases of lymph nodes or organ metastases from breast cancer, and 90 cases of non-breast primary carcinoma tissues were analyzed. RESULTS: All 3 anti-hMAM antibodies showed high positive expression of hMAM in primary breast cancers, benign, and normal breast tissues. The positive ratio for MEF521 (33.3%) or MDA822 (44.4%) was much higher than that of ab81611 (16.7%) in lymph node metastasis from breast cancer (p = 0.038). There was no correlation between hMAM expression and clinicopathologic features of breast cancer in the 3 groups of antibodies. In 90 cases of non-breast primary carcinoma tissues, no hMAM-positive ones were observed in the MEF521 or MDA822 group, but 48 (53.3%) in the ab81611 group were positive, indicating that breast tissue specificity of the 2 self-made anti-hMAM monoclonal antibodies much higher than that of ab81611 (p<0.001). CONCLUSIONS: Our results showed that MDA822 and MEF521 are more specific to breast cancer as measured by means of immunohistochemistry. Therefore, the 2 self-made anti-hMAM antibodies may have good prospects for clinical application in the differential diagnosis of breast tumor and breast cancer metastases.

Generation of monoclonal antibodies against MGA and comparison of their application in breast cancer detection by immunohistochemistry.

Mammaglobin A (MGA) is an organ specific molecular biomarker for metastatic breast cancer diagnosis. However, there are still needs to develop optimal monoclonal antibodies (mAbs) to detect MGA expression in breast carcinoma by immunohistochemistry. In this study, we first generated mAbs against MGA. Then, we used epitope prediction and computer-assisted structural analysis to screen five dominant epitopes and identified mAbs against five epitopes. Further immunohistochemical analysis on 42 breast carcinoma specimens showed that MHG1152 and MGD785 had intensive staining mainly in membrane, while CHH11617, CHH995 and MJF656 had more intensive staining within the cytoplasm. MGA scoring results showed that MJF656 had the highest rate (92.8%) of positive staining among five mAbs, including higher staining intensity when compared with that of MHG1152 (p < 0.01) and CHH995 (p < 0.05) and the highest the mean percentage of cells stained among mAbs. Furthermore, we analyzed the relationship of positive staining rate by mAbs with patient clinical characteristics. The results suggest that MJF656 was able to detect MGA expression, especially in early clinical stage, low grade and lymph node metastasis-negative breast carcinoma. In conclusion, our study generated five mAbs against MGA and identified the best candidate for detection of MGA expression in breast cancer tissues.

Cross-reactivity of hypervariable region 1 chimera of hepatitis C virus.

AIM: To analyze the amino acid sequences of hypervariable region 1 (HVR1) of HCV isolates in China and to construct a combinatorial chimeric HVR1 protein having a very broad high cross-reactivity. METHODS: All of the published HVR1 sequences from China were collected and processed with a computer program. Several representative HVR1's sequences were formulated based on a consensus profile and homology within certain subdivision. A few reported HVR1 mimotope sequences were also included for a broader representation. All of them were cloned and expressed in E.coli. The cross-reactivity of the purified recombinant HVR1 antigens was tested by ELISA with a panel of sera from HCV infected patients in China. Some of them were further ligated together to form a combinatorial HVR1 chimera. RESULTS: Altogether 12 HVR1(s) were selected and expressed in E.coli and purified to homogeneity. All of these purified antigens showed some cross-reactivity with sera in a 27 HCV positive panel. Recombinant HVR1s of No. 1, 2, 4, and 8# showing broad cross-reactivities and complementarity with each other, were selected for the ligation elements. The chimera containing these 4 HVR1s was highly expressed in E.coli. The purified chimeric antigen could react not only with all the HCV antibody positive sera in the panel but also with 90/91 sera of HCV -infected patients. CONCLUSION: The chimeric antigen was shown to have a broad cross-reactivity. It may be helpful for solving the problem caused by high variability of HCV, and in the efforts for a novel vaccine against the virus.

[Studies on the correlation between titer of antibodies against different function regions of hepatitis C virus and HCV RNA of chronic patients].

OBJECTIVE: To detect humoral immune response against different function regions of hepatitis C virus (HCV) in chronic patients, and further to investigate the correlativity between anti-HCV antibody titers and HCV RNA concentration. METHODS: Using recombinant dominate epitope antigens, e.g. HCV Core, NS3, NS4, NS5 and chimeric HVR1, a set of ELISA test reagents was formulated. Then, titers of antibodies against HCV different regions and the RNA concentration of HCV in chronic patient sera were detected by ELISA and quantitative RT-PCR technique, respectively. RESULTS: Great differences have been noted in antibody titers and positive rate of different HCV function regions in chronic patients. Antibodies against HCV Core and HVR1 have the highest positive rate, then NS3, NS4, and NS5 in sequence. CONCLUSION: The titer of antibodies against different regions of HCV in chronic patients has good correlation with HCV RNA concentration.

Construction of an immunostimulatory plasmid, pUCpGs10, and research on its immune adjuvant effect.

In order to overcome the instability of CpG ODN in vivo, sequence diversity, and individual differences, eleven CpG ODN fragments were meticulously selected and linked to form a Multi-CpG, which were repeatedly inserted into the cloning vector pUC19 for constructing the recombinant plasmid pUCpGs10 containing ten of Multi-CpG. Using the multi-genotype HCV E1 and multi-epitope complex HCV-T as immunogens, and plasmid pUCpGs10 as the immune adjuvant, Balb/c mice were immunized through nasal and subcutaneous immunization. Strong-specific humoral and cellular immune response were induced, which can obviously inhibit the growth of homograft expressing HCV antigen. The immune adjuvant effect of pUCpGs10 closely matched that of Freund's complete adjuvant. The plasmid pUCpGs10 can significantly improve IgA content in serum and different mucosal extract and systematical T-cell response via intranasal immunization. In conclusions, the newly constructed immunostimulatory plasmid pUCpGs10 is able to effectively activate the humoral and cellular immune activity, and possesses activation on mucosal immune response.

Enhanced serodiagnostic utility of novel Mycobacterium tuberculosis polyproteins.

OBJECTIVES: The detection of Mycobacterium tuberculosis specific antibodies in human sera has been a rapid and important diagnostic aid for tuberculosis (TB) control and prevention. However, any single antigen is not enough to be used to cover the antibody profiles of all TB patients. METHODS: Seven single antigens (38 kDa, ESAT-6, CFP10, Mtb8.4, MPT64, TB16.3 and Mtb8) were evaluated serodiagnostically. Two novel M. tuberculosis polyproteins, 38kD-ESAT6-CFP10 (38F) and Mtb8.4-MPT64-TB16.3-Mtb8 (64F), were expressed and the novel 38F-64F indirect ELISA assay used to analyze antibody responses to polyproteins in serum samples. RESULTS: The sensitivity of the novel 38F-64F indirect ELISA alone was much higher than that of the sputum culture test (86.91% vs. 50.62%) and that of the sputum smear test (78.64% vs. 47.57%). The novel 38F-64F indirect ELISA had a sensitivity of 74.16% with sera from extrapulmonary TB patients and a sensitivity of 37.14% with sera from LTBI. The specificity of the novel 38F-64F indirect ELISA was 90.36% with the sera from healthy blood donors and 94.15% with the sera from non-TB patients. CONCLUSIONS: The novel 38F-64F indirect ELISA assay had effective diagnostic performance and would make meaningful contribution to the diagnosis of TB disease in developing countries.

Double-antigen sandwich ELISA for the detection of anti-hepatitis C virus antibodies.

A double-antigen sandwich ELISA was developed a detection of HCV antibodies by a recombinant multi-epitope HCV antigen and a biotin-streptavidin amplification system. Three plasma specimens from 1708 individuals who were suspected previously to be HCV-positive using an HCV antibody diagnostic kit (Chuangxin, Xiamen, China) displayed negative results when using the ELISA. These results were validated by a recombinant immunoblotting assay (two were negative, and one was indeterminate). Among 889 blood specimens donated for clinical evaluation, 246 were positive and 630 were negative using the ELISA. The sensitivity and specificity of the ELISA were 98.7% and 100%, respectively. In 43 donors and 14 patients with chronic hepatitis C, the detectable rates for HCV IgM by both ELISA and the HCV anti-IgM detection reagents (Huimin, Shenyang, China) were 100%, and the detectable rate for HCV IgG using an indirect HCV-antibody detection kit (GWK, Beijing, China) was 98.3%. Thus, the double-antigen sandwich ELISA exhibits strong specificity and sensitivity and has been approved by the China State Food and Drug Administration (SFDA). The performance of the double-antigen sandwich ELISA was similar to the Ortho ELISA 3.0. It did not give false-negative results otherwise IgM was undetectable using an indirect HCV-antibody detection kit. This ELISA provides another method for the detection of HCV antibodies.

Hepatitis C virus core protein promotes the migration and invasion of hepatocyte via activating transcription of extracellular matrix metalloproteinase inducer.

The chronic infection of hepatitis C virus (HCV) becomes a main factor evoking hepatocellular carcinoma, where the HCV core protein plays a central role in hepatocarcinogenesis. Whether the core protein directly contributes to metastasis of hepatocytes still remains to be reported in literature. Transwell chamber migration assay, Boyden chamber invasion assays and scanning electron microscopy observations were performed to determine the prometastatic ability of HCV core protein when expressed in human hepatocyte L02 cells. In addition, western blots, dual-luciferase assays, and chromatin immunoprecipitation assays were used to elucidate HCV core protein dependent pathways that promote metastasis in hepatocytes. Our investigation suggests that HCV core protein markedly enhances the capability of migration and invasion in L02 clones expressing HCV core proteins. The metastasis-promoting effect of the core protein is, in part, highly dependent on its effect on promoting the binding of transcription factor Sp1 to the extracellular matrix metalloproteinase inducer promoter. The effect of Sp1 binding resulted in an increase in extracellular matrix metalloproteinase inducer expression and progression of metastasis. Thus, we report that the expression of HCV core protein contributes to the metastasis of hepatocyte cells through activating transcription of extracellular metalloproteinase inducer.

Construction, expression, purification and biotin labeling of a single recombinant multi-epitope antigen for double-antigen sandwich ELISA to detect hepatitis C virus antibody.

Based on B cell epitope predictions, a recombinant antigen with multiple epitopes from four Hepatitis C Virus fragments (C, NS3, NS4 and NS5) were engineered. The recombinant gene was then highly expressed in E. coli. The non-modified and C-terminal-modified recombinant proteins were used for coating and biotin labeling, respectively, to establish the double-antigen sandwich ELISA. Ten positive reference samples confirmed by the CHIRON RIBA HCV 3.0 SIA kit were detected positive, Forty one plasma samples were positive among samples from 441 volunteers, which indicated that the recombinant antigen could readily react well with plasma HCV antibody. As critical reagents of double-antigen sandwich ELISA, the recombinant multi-epitope antigen and the C-terminal-modified and biotin-conjugated antigen show good antigenicity. In this study, we provide a simple approach to produce multiple epitopes within one recombinant protein in order to avoid the costly expression of less-effective pools of multiple proteins, which is the conventional strategy of diagnostic antigen production for HCV antibody detection.

Evaluation of cross-reactive antibody response to HVR1 in chronic hepatitis C.

AIM: To evaluate the presence and cross-reactive antibodies against hypervariable region 1 (HVR1) in hepatitis C virus (HCV) infected patients and its relationship with the progression of the disease. METHODS: Sixteen representative HVR1 proteins selected from a unique set of 1600 natural sequences were used to semiquantitate the cross-reactivity of HVR1 antibodies in the sera of HCV patients. Fifty-five chronic HCV patients including 23 with asymptomatic mild hepatitis, 18 with chronic hepatitis and 16 with liver cirrhosis patients were studied. RESULTS: The degree of the cross-reactivity of anti-HVR1 antibodies in 23 patients with mild asymptomatic hepatitis was 3.09 ± 2.68, which was significantly lower than in those with chronic hepatitis (5.44 ± 3.93, P < 0.05) and liver cirrhosis (7.44 ± 3.90, P < 0.01). No correlation was observed between the broadness of the cross-reactivity anti-HVR1 antibodies and patient's age, infection time, serum alanine aminotransferase activity, or serum HCV-RNA concentration. It was the breath of cross-reactivity rather than the presence of anti-HVR1 antibody in HCV sera that was associated with the progression of liver disease. CONCLUSION: The broadly cross-reactive HVR1 antibodies generated in natural HCV patients can not neutralize the virus, which results in persistent infection in patients with chronic hepatitis.