Neutralizing antibodies against adenovirus type 2 in normal and HIV-1-infected subjects: Implications for use of Ad2 vectors in vaccines.

Pre-existing neutralizing antibodies (NAbs) directed against vaccine vectors have attracted considerable research attention. Therefore, our aim was to establish a high-throughput economical neutralization assay to investigate the epidemiology of adenovirus type 2 (Ad2)-specific immunity in China and developed countries, including in a Chinese Human immunodeficiency virus (HIV)-1-infected population, and to guide the application of Ad2-vectored vaccines. We established a FluoroSpot-based anti-Ad2-virus neutralization assay using a recombinant replication-deficient Ad2 that expresses enhanced green fluorescent protein and standardized the critical parameters, including the choice of cell line, cell concentration, viral infective dose, and incubation time.

Regulation and quality evaluation system for HIV diagnostics in China.

A sophisticated regulatory framework has been constructed for Human immunodeficiency virus (HIV) diagnostics in China, which have developed over the past 30 years. China National Institutes for Food and Drug Control acts as the legal institution in this regulatory framework, launching important activities to ensure the quality of HIV diagnostics. These include the analysis of the main problems faced in developing domestic HIV diagnostics, by investigating the quality of HIV diagnostics and their development; exploring the key factors affecting the quality of HIV diagnostics, to determine the criteria for screening national reference samples; the development of new technologies and methods for preparing reference samples; and the establishment of nine types of national reference panels and nine national standards to evaluate the quality of HIV diagnostics.

Hepatitis E genotype 4 virus from feces of monkeys infected experimentally can be cultured in PLC/PRF/5 cells and upregulate host interferon-inducible genes.

The understanding of the interaction between hepatitis E virus (HEV) and its host cells has been impeded greatly by the absence of a cell culture system. In this study, an efficient cultivation method was developed in PLC/PRF/5 cells for HEV genotype 4 from the feces of monkeys infected experimentally. Compared to minimal essential medium (MEM), mixed Dulbecco's Modified Eagle's Medium (DMEM)/M199 improved the infection efficiency of HEV in PLC/PRF/5 cells.

Bisulfite and sulfite as derivatives of sulfur dioxide alters biomechanical behaviors of airway smooth muscle cells in culture.

Sulfur dioxide (SO2) is a common air pollutant that triggers asthmatic symptoms, but its toxicological mechanisms are not fully understood. Specifically, it is unclear how SO2 in vivo affects airway smooth muscle (ASM) cells of which the mechanics is known to ultimately mediate airway hyperresponsiveness (AHR) - a hallmark feature of asthma. To this end, we investigated the effects of bisulfite/sulfite (1:3 M/M in neutral fluid to simulate the in vivo derivatives of inhaled SO2 in the airways), on the viability, migration, stiffness and contractility of ASM cells cultured in vitro.

[A flexion loading system for knee biomechanics research].

It is important to design and build a kinetic loading system for flexing movement of knee joint to study knee biomechanics. The system reported here includes driving device, control device, and flexion angle determination imaging system. The driving device was constructed with a stepper motor and a mechanical transmission with a serried of clamps, shanks and so on, and the driving device was controlled by the control device with micro-control unit, a computer and the serial 232.

Chronic exposure to sulfur dioxide enhances airway hyperresponsiveness only in ovalbumin-sensitized rats.

Sulfur dioxide (SO(2)) is a common air pollutant that triggers asthmatic symptoms, but its toxicological mechanisms are not fully understood. Specifically, it is unclear how airborne SO(2) affects airway hyperresponsiveness (AHR) - a hallmark feature of asthma. To this end, we investigated the effects of chronic exposure to SO(2) on AHR, airway inflammation, tissue remodeling, cell stiffness (G') and contractility of the airway smooth muscle cell (ASMC).

Optimization and proficiency testing of a pseudovirus-based assay for detection of HIV-1 neutralizing antibody in China.

Among the neutralizing antibody evaluation assays, the single-cycle pseudovirus infection assay is high-throughput and can provide rapid, sensitive and reproducible measurements after a single cycle of infection. Cell counts, pseudovirus inoculation levels, amount of diethylaminoethyl-dextran (DEAE-dextran), and the nonspecific effects of serum and plasma were tested to identify the optimal conditions for a neutralizing antibody assay based on pseudoviruses. Optimal conditions for cell counts, pseudovirus inoculation, and amount of DEAE-dextran were 1 × 10(4)cells/well, 200TCID(50)/well, and 15 μg/ml, respectively.

A novel high-throughput vaccinia virus neutralization assay and preexisting immunity in populations from different geographic regions in China.

Background: Pre-existing immunity to Vaccinia Tian Tan virus (VTT) resulting from a large vaccination campaign against smallpox prior to the early 1980s in China, has been a major issue for application of VTT-vector based vaccines. It is essential to establish a sensitive and high-throughput neutralization assay to understand the epidemiology of Vaccinia-specific immunity in current populations in China.

Methodology/principal Findings: A new anti-Vaccinia virus (VACV) neutralization assay that used the attenuated replication-competent VTT carrying the firefly luciferase gene of Photinus pyralis (rTV-Fluc) was established and standardized for critical parameters that included the choice of cell line, viral infection dose, and the infection time.

Comparison between the automated Roche Cobas AmpliPrep/Cobas TaqMan HIV-1 test version 2.0 assay and its version 1 and Nuclisens HIV-1 EasyQ version 2.0 assays when measuring diverse HIV-1 genotypes in China.

Background: Several commercially available HIV-1 viral load assays based on real-time detection technology and automated platforms are available. It is not clear how the diversity of HIV-1 genotypes impacts the ability to consistently detect HIV-1 viral loads.

Objectives: To examine whether the diversity of HIV-1 genotypes impacts the ability of the Cobas AmpliPrep/Cobas TaqMan HIV-1 test version 2.

Comparative evaluation of the ViroSeq™ HIV-1 genotyping system and an in-house method for analysis of HIV-1 drug-resistance mutations in China.

Background And Objective: With the introduction of the ViroSeq™ HIV-1 Genotyping System (ViroSeq™ assay) into China, it is important to evaluate the impact of the diversity of HIV-1 genotypes found in China on the performance of the ViroSeq™ assay compared with an in-house method.

Materials And Methods: A total of 318 plasma samples, collected from 206 HIV-1-infected patients receiving antiretroviral therapy and 112 treatment-naïve HIV-1-infected patients, were used for evaluating the concordance of genotypes, genotypic resistance mutations, and phenotypic resistance between the ViroSeq™ assay and an in-house method for analyzing HIV-1 drug resistance in China.

Results: A concordance of genotypes between the ViroSeq™ assay and the in-house method was observed for the 313 samples (98.

The serological prevalence and genetic diversity of hepatitis E virus in farmed rabbits in China.

We identified and characterized a novel virus, designated rabbit hepatitis E virus (HEV), in rex rabbits farmed in China. Rabbit HEV is genetically related to but distinct from other known mammalian HEVs and avian HEV and may represent a novel genotype. To evaluate the spread and genetic variation of rabbit HEV, a total of 1094 serum samples were collected from various breeds of rabbits across ten counties in China.

Performance of NucliSens HIV-1 EasyQ Version 2.0 compared with six commercially available quantitative nucleic acid assays for detection of HIV-1 in China.

Background And Objectives: Six HIV-1 viral load assays have been widely used in China. These include the Cobas Amplicor HIV-1 Monitor Version 1.5 ('Amplicor'), Cobas AmpliPrep/Cobas TaqMan HIV-1 test Version 1.

The effect of human immunodeficiency virus type 1 (HIV-1) gp41 variability on antibody detection.

To determine whether genetic variability influences the ability to detect antibody, nine gp41 ectodomain recombinant proteins from human immunodeficiency virus type 1 (HIV-1) CRF07_BC, CRF01_AE and subtype B' were expressed in a bacterial expression system and purified. An indirect sandwich ELISA was developed with individual purified recombinant proteins. Plasma samples from 26 individuals infected with HIV-1 of different subtypes and four samples from the 1st international antibody reference panel were tested against each recombinant protein by ELISA.

Performance of the automated COBAS AmpliPrep/COBAS TaqMan HIV-1 test on a genetically diverse panel of specimens from China: comparison to the COBAS amplicor HIV-1 monitor test, v1.5.

Objectives: To investigate the impact of genetically diverse HIV samples from China on the performance of the automated COBAS(R) AmpliPrep/COBAS TaqMan(R) HIV-1 Test (CAP/CTM).

Methods: 185 samples from untreated HIV-1-infected patients were used to assess the performance of the CAP/CTM Test and COBAS Amplicor HIV-1 Monitor Test, v1.5 (Cobas).

Development and evaluation of a national reference panel of HIV-1 protease and reverse transcriptase drug-resistance mutations for HIV-1 genotypic resistance assays in China.

Background: Transmission of antiretroviral drug-resistant strains of HIV-1 has a major impact on the success of HIV treatment regimens in most countries where antiretroviral therapy (ART) is available. It is now recommended that HIV-1 drug resistance be monitored in order to recommend appropriate therapy for infected ART-naïve individuals, or when choosing a new regimen for those patients not responding to ART. Commercial assays for the analysis of HIV-1 genotypic resistance have been approved by the US FDA.

Genotypic and phenotypic characterization of HIV-1 CRF01_AE env molecular clones from infections in China.

Background: Although a great number of HIV-1 pseudoviruses have been generated for neutralization assays, circulating recombinant forms, such as CRF01_AE, are not included. Given the increasing prevalence of CRF01_AE, the establishment of a pool of CRF01_AE env isolates for the evaluation of potential HIV vaccines is needed.

Materials And Methods: Full-length env genes were cloned from HIV-1 CRF01_AE-infected plasma samples collected in China and used to establish Env-pseudotyped viruses.

A novel genotype of hepatitis E virus prevalent among farmed rabbits in China.

In total, 335 serum samples were collected from rabbits from two farms in Gansu province, China, and tested for anti-hepatitis E virus (HEV) antibody using EIA and for HEV RNA using nested RT- PCR with ORF2 primers. The overall prevalence of anti-HEV antibody and HEV RNA was 57.0% (191/335) and 7.

Relationships among viral diagnostic markers and markers of liver function in acute hepatitis E.

Background: Diagnosis of acute hepatitis E has been based in many clinics predominantly on detection of anti-HEV (hepatitis E virus) antibody. Now, new assays have been developed to detect other HEV markers. Our aim was to investigate the relationships among HEV diagnostic markers and liver function markers in acute hepatitis E.

Comparative evaluation of the COBAS AmpliPrep/COBAS TaqMan HIV type 1 test (CAP/CTM) and VERSANT HIV type 1 RNA 3.0 assay (bDNA) for quantifying HIV type 1 viral loads in China.

In the present study, 277 clinical samples from untreated and treated HIV-1-infected patients with different clades were used to assess the agreement between the COBAS AmpliPrep/COBAS TaqMan HIV-1 test (CAP/CTM) and VERSANT HIV-1 RNA 3.0 Assay (bDNA). A qualitative comparison of the results of the two assays showed concordance for 255 positive and 15 negative samples (94.

Investigation of hepatitis E virus infection in swine from Hunan province, China.

Nine hundred and four serum samples were collected from pigs from 16 pig farms in China's Hunan province and tested for anti-hepatitis E virus (HEV) antibody and the HEV capsid antigen using EIAs. Of the 904 samples, 617 (68.3%) and 57 (6.

[Epidemiological survey on the infection of hepatitis E virus among pigs in Henan province].

Objective: To investigate hepatitis E virus (HEV) infection among pigs in Henan province.

Methods: A total of 623 swine sera, collected from 5 districts, were divided into two groups, under 3-month of age and over 3-month of age. They were tested for HEV antigen and antibody by using ELISAs, respectively.

Performance of the Abbott RealTime HIV-1 assay for quantification of HIV-1 clades prevalent in China.

Objective: To evaluate the performance of the Abbott RealTime HIV-1 assay for measuring viral loads of the prevalent HIV-1 clades in China.

Study Design: Serially diluted samples, as well as 521 clinical samples from 213 untreated HIV-1-infected individuals, 56 HIV-1-infected patients receiving ART, 60 HCV- and 57 HBV-infected patients and 135 healthy blood donors, were tested with RealTime and EasyQ.

Results: Both assays exhibited linearity coefficients of >0.

Genetic and neutralization properties of HIV-1 env clones from subtype B/BC/AE infections in China.

Background: As HIV vaccines move into preclinical and clinical trials in China, pseudovirion-based neutralization assays, especially those using env genes of Chinese origin, are widely required to evaluate the ability of HIV vaccines to induce neutralizing antibody (nAb) responses.

Materials And Methods: Functional gp160 genes from plasma samples from Chinese HIV-infected patients were cloned and sequenced and then used to establish a pseudovirus-based neutralization assay. The neutralization phenotypes of the Env-pseudotyped viruses were characterized with known nAbs (4E10, 2F5, IgG1b12, and 2G12) and 43 plasma samples from patients infected with different HIV subtypes.

Impact of HIV-1 genetic diversity in China on the measurement of viral load.

In this study, 190 HIV-positive samples were collected from different regions of China. The HIV clades of 153 samples were determined successfully based on env sequencing. Specifically, 48, 5, 87, and 13 isolates belonged to clades B', B, BC, and AE, respectively.