Improvement in the 95-95-95 Targets Is Accompanied by a Reduction in Both the Human Immunodeficiency Virus Transmission Rate and Incidence in China.

BACKGROUND: In 2016, China has implemented the World Health Organization's "treat all" policy. We aimed to assess the impact of significant improvements in the 95-95-95 targets on population-level human immunodeficiency virus (HIV) transmission dynamics and incidence. METHODS: We focused on 3 steps of the HIV care continuum: diagnosed, on antiretroviral therapy, and achieving viral suppression. The molecular transmission clusters were inferred using HIV-TRACE. New HIV infections were estimated using the incidence method in the European Centre for Disease Prevention and Control HIV Modelling Tool. RESULTS: Between 2004 and 2023, the national HIV epidemiology database recorded 2.99 billion person-times of HIV tests and identified 1 976 878 new diagnoses. We noted a roughly "inverted-V" curve in the clustering frequency, with the peak recorded in 2014 (67.1% [95% confidence interval, 63.7%-70.5%]), concurrent with a significant improvement in the 95-95-95 targets from 10-13-<71 in 2005 to 84-93-97 in 2022. Furthermore, we observed a parabolic curve for a new infection with the vertex occurring in 2010. CONCLUSIONS: In general, it was suggested that the improvements in the 95-95-95 targets were accompanied by a reduction in both the population-level HIV transmission rate and incidence. Thus, China should allocate more effort to the first "95" target to achieve a balanced 95-95-95 target.

Trends and Patterns of HIV Transmitted Drug Resistance in China From 2018 to 2023.

BACKGROUND: National treatment guidelines of China evolving necessitates population-level surveillance of transmitted drug resistance (TDR) to inform or update HIV treatment strategies. METHODS: We analyzed the demographic, clinical, and virologic data obtained from people with HIV (PWH) residing in 31 provinces of China who were newly diagnosed between 2018 and 2023. Evidence of TDR was defined by the World Health Organization list for surveillance of drug resistance mutations. RESULTS: Among the 22 124 PWH with protease and reverse transcriptase sequences, 965 (4.36%; 95% CI, 4.1-4.63) had at least 1 TDR mutation. The most frequent TDR mutations were nonnucleoside reverse transcriptase inhibitor (NNRTI) mutations (2.39%; 95% CI, 2.19%-2.59%), followed by nucleoside reverse transcriptase inhibitor mutations(1.35%; 95% CI, 1.2%-1.5%) and protease inhibitor mutations (1.12%; 95% CI, .98%-1.26%). The overall protease and reverse transcriptase TDR increased significantly from 4.05% (95% CI, 3.61%-4.52%) in 2018 to 5.39% (95% CI, 4.33%-6.57%) in 2023. A low level of integrase strand transfer inhibitor TDR was detected in 9 (0.21%; 95% CI, .1%-.38%) of 4205 PWH. CONCLUSIONS: Presently, the continued use of NNRTI-based first-line antiretroviral therapy regimen for HIV treatment has been justified.

[Analysis on factors associated with taking subsequent confirmation test among men who have sex with men after being tested positive in oral fluid HIV antibody test in Beijing].

OBJECTIVE: To analyze the proportion and associated factors of taking subsequent confirmation test among men who have sex with men (MSM) after being tested positive in oral fluid HIV antibody test. METHODS: By using successive sampling, 1 003 MSM, who were tested positive in oral fluid HIV antibody test in China-Bill & Melinda Gates Foundation AIDS prevention Program (Extension program) in Beijing during May 1 to December 31, 2013, were recruited. The inclusion criteria included: the objects were men who reported having sex with men; the objects aged more than 18 years old; the objects were tested positive in oral fluid HIV antibody test; the objects had not been reported as HIV positives in China Information System for Disease Control and Prevention previously. According to the program strategy, MSM grassroots organizations transferred the respondents to seek subsequent confirmation tests in specific Center for Disease Control and Prevention (CDCs) or hospitals. The subsequent confirmation tests included: fingertip blood HIV antibody rapid test, venous blood Enzyme Linked Immunosorbent Assay (ELISA) HIV antibody test and venous blood Western Blot (WB) HIV antibody test. Chi-square test was adopted to compare the proportion of taking subsequent confirmation tests in different groups. Nonconditional multivaritae binarylogistic regression analysis was taken to identify the associated factors with whether taking subsequent confirmation tests and to calculate the OR (95% CI) values. RESULTS: The 1 003 respondents were (30.9 ± 9.1) years old. Among all objects, 87.8% (881/1 003) of them took fingertip blood HIV antibody rapid tests and the positive rate was 85.4% (752/881). 98.0% (737/752) of those who were identified as positive in fingertip blood HIV rapid tests took ELISA and WB tests, and the positive rate was 94.4% (696/737). Comparing with those who were expected to seek subsequent confirmation tests in CDCs, the OR (95% CI) value of those who were expected to seek tests in hospitals was 5.10 (1.69-15.36). The OR (95% CI) values of those who used condom sometimes and those who never used condom in anal sex were 5.81 (2.14-15.77) and 3.45 (2.00-5.97) respectively, in comparison with those who reported not having anal sex or using condom consistently in anal sex during the past 6 months. Comparing with the respondents recruited from the internet, the OR (95% CI) values of those recruited in bathrooms, parks/toilets and bars were 0.17 (0.05-0.53), 0.10 (0.04-0.29) and 0.22 (0.06-0.79) respectively. The likelihood of taking subsequent confirmation test decreased with the increase of number of male sexual partners in the past 3 months, and the OR (95% CI) value was 0.92 (0.86-0.99). CONCLUSION: The potential HIV positive MSM in the bathroom, park/toilet and bars are less likely to take subsequent confirmation test. Those who do not use condom consistently during anal sex are more likely to seek subsequent confirmation test. Medical organization conducting subsequent confirmation tests is more likely to increase the confirmation test rate of potential HIV positive MSM. The number of male sexual partners has negative correlation with whether to accept the subsequent confirmation test.

[Molecular epidemiological characteristics of HIV-1 B'/C strains in Beijing].

OBJECTIVE: To analyze the molecular epidemiological characteristic of HIV-1 B'/C strains prevalent in Beijing. METHODS: Plasma samples were collected from 200 newly diagnosed HIV-1 B'/C individuals reported during 2006 to 2010 in Beijing. The gag gene fragments were amplified from RNA template extracted from plasma with reverse transcription (RT) and nested polymerase chain reaction (PCR). And the sequences were analyzed by phylogenetic methods and Entropy analysis. RESULTS: A total of 159 sequences were successfully amplified from the gag genes of which 147 was CRF07_BC and 12 CRF08_BC. There were 3 main sub-clusters in CRF07_BC phylogenetic tree and they were named as sub-cluster IDU-Max (89 sequences), sub-cluster IDU-Min (22 sequences) and sub-cluster MSM (34 sequences) based on transmission.No international reference strain was closely related with these three sub-clusters except for one strain identified in Taiwan. All CRF07_BC recombinant strains were remarkable for their low interpatient diversity in gag genes (3.7%, 3.3% and 2.0% for isolates from IDU-Max, IDU-Min and MSM respectively).When compared with sub-cluster IDU-Max, there were 32 and 41 significantly different sites of nucleotide polymorphism compositions in sub-clusters IDU-Min and MSM. CONCLUSION: This is the first report of describing the existence of three main epidemic sub-clusters in CRF07_BC strains prevalent in Beijing. And IDU-Max sub-cluster is the dominant strain. The CRF07_BC in Beijing are less diverse than other strains and may be derived from a common ancestor.

Awareness and use of HIV pre-exposure prophylaxis and factors associated with awareness among MSM in Beijing, China.

Human immunodeficiency virus (HIV) sexual transmission among men who have sex with men (MSM) has increased markedly in Beijing, China in the past decade. Pre-exposure prophylaxis (PrEP) is a highly efficacious biomedical prevention strategy that remarkably reduces HIV-transmission risk. This study examined PrEP awareness among MSM and the factors influencing it. From April to July 2021, respondent-driven sampling was used to conduct a cross-sectional survey among MSM in Beijing, China. Demographic, behavior, and awareness data regarding PrEP were collected. The factors influencing PrEP awareness were assessed using univariate and multivariable logistic regression. In total, 608 eligible responders were included in the study. Among the respondents, 27.9% had PrEP awareness, 3.3% had taken PrEP, and 57.9% expressed interest in receiving PrEP, if required. Greater odds of PrEP awareness were associated with higher education level (adjusted odds ratio [aOR] 3.525, 95% confidence interval [CI] 2.013-6.173, P < 0.0001), greater HIV-related knowledge (aOR 3.605, 95% CI 2.229-5.829, P < 0.0001), HIV testing (aOR 2.647, 95% CI 1.463-4.788, P = 0.0013), and sexually transmitted infections (aOR 2.064, 95% CI 1.189-3.584, P = 0.0101). Lower odds of PrEP awareness were associated with higher stigma score (aOR 0.729, 95% CI 0.591-0.897, P = 0.0029). The findings indicate sub-optimal awareness and low utilization of PrEP in Beijing and highlight PrEP inequities among MSM with stigma. Strengthening the training of peer educators in disseminating PrEP knowledge and reducing stigma are critical for improving PrEP awareness.

Distribution pattern, molecular transmission networks, and phylodynamic of hepatitis C virus in China.

In China, few molecular epidemiological data on hepatitis C virus (HCV) are available and all previous studies were limited by small sample sizes or specific population characteristics. Here, we report characterization of the epidemic history and transmission dynamics of HCV strains in China. We included HCV sequences of individuals belonging to three HCV surveillance programs: 1) patients diagnosed with HIV infection at the Beijing HIV laboratory network, most of whom were people who inject drugs and former paid blood donors, 2) men who have sex with men, and 3) the general population. We also used publicly available HCV sequences sampled in China in our study. In total, we obtained 1,603 Ns5b and 865 C/E2 sequences from 1,811 individuals. The most common HCV strains were subtypes 1b (29.1%), 3b (25.5%) and 3a (15.1%). In transmission network analysis, factors independently associated with clustering included the region (OR: 0.37, 95% CI: 0.19-0.71), infection subtype (OR: 0.23, 95% CI: 0.1-0.52), and sampling period (OR: 0.43, 95% CI: 0.27-0.68). The history of the major HCV subtypes was complex, which coincided with some important sociomedical events in China. Of note, five of eight HCV subtype (1a, 1b, 2a, 3a, and 3b), which constituted 81.8% HCV strains genotyped in our study, showed a tendency towards decline in the effective population size during the past decade until present, which is a good omen for the goal of eliminating HCV by 2030 in China.

CRF07_BC is associated with slow HIV disease progression in Chinese patients.

HIV subtypes convey important epidemiological information and possibly influence the rate of disease progression. In this study, HIV disease progression in patients infected with CRF01_AE, CRF07_BC, and subtype B was compared in the largest HIV molecular epidemiology study ever done in China. A national data set of HIV pol sequences was assembled by pooling sequences from public databases and the Beijing HIV laboratory network. Logistic regression was used to assess factors associated with the risk of AIDS at diagnosis ([AIDSAD], defined as a CD4 count < 200 cells/µL) in patients with HIV subtype B, CRF01_AE, and CRF07_BC. Of the 20,663 sequences, 9,156 (44.3%) were CRF01_AE. CRF07_BC was responsible for 28.3% of infections, followed by B (13.9%). In multivariable analysis, the risk of AIDSAD differed significantly according to HIV subtype (OR for CRF07_BC vs. B: 0.46, 95% CI 0.39─0.53), age (OR for ≥ 65 years vs. < 18 years: 4.3 95% CI 1.81─11.8), and transmission risk groups (OR for men who have sex with men vs. heterosexuals: 0.67 95% CI 0.6─0.75). These findings suggest that HIV diversity in China is constantly evolving and gaining in complexity. CRF07_BC is less pathogenic than subtype B, while CRF01_AE is as pathogenic as B.

[Genotypic resistance mutations to antiretroviral drugs in newly confirmed human immunodeficiency virus infectors in Beijing].

OBJECTIVE: To examine the prevalence of drug resistance mutations among the treatment-naive HIV (human immunodeficiency virus) infectors living in Beijing so as to provide the basal information for clinical antiviral treatment. METHODS: HIV pol genes from plasma samples of 150 treatment-naive HIV-infected patients were amplified, sequenced and phylogenetically analyzed. And the drug-resistance associated mutations in protease and reverse transcriptase regions were analyzed with Stanford University HIV Drug Resistance Database. RESULTS: A total of 111 pol gene sequences were obtained. The overall prevalence of drug resistance was 8.1% (9/111), corresponding to 3.6% (4/111) for protease inhibitors, 1.8% (2/111) for nucleoside reverse transcriptase inhibitors and 3.6% (4/111) for non-nucleoside reverse transcriptase inhibitors. No drug resistance mutation was identified in 17 intravenous drug users. CONCLUSION: The prevalence of drug resistance is relatively high in the newly confirmed HIV infectors in Beijing. Regular surveillance and monitoring of drug-resistant HIV should be implemented.

Awareness and Use of Post-exposure Prophylaxis for HIV Prevention Among Men Who Have Sex With Men: A Systematic Review and Meta-Analysis.

Background: The use of post-exposure prophylaxis (PEP) is effective in reducing HIV risk, but it is underused by men who have sex with men (MSM) due to certain psychological and sociostructural factors. This article assessed the awareness and use of PEP among MSM in an effort to increase the visibility and uptake of PEP among at-risk populations. Methods: We conducted a systematic literature search of the PubMed, Web of Science, PsycINFO, and Google Scholar electronic databases. Studies were screened for inclusion, and relevant data were abstracted, assessed for bias, and synthesized. Pooled effect estimates were calculated using random effects meta-analysis, meta-regression and subgroup analysis, and a qualitative review and risk of bias assessment were performed (PROSPERO, CRD42019123815). Results: Twenty eligible studies involving 12,579 MSM were included in the meta-analysis. The pooled estimate of the proportions of MSM who were aware of PEP was modest at 59.9% (95% CI: 50.5~68.7) and that of MSM who previously used PEP was very low at 4.9% (95% CI: 2.4~9.8). PEP awareness showed no clear change over time, while PEP use significantly changed over time. Multiple factors affected awareness, including educational attainment, race/ethnicity, levels of HIV stigma, access to condoms, and so on. Many factors could potentially impede or facilitate the use of PEP, such as income, lack of PEP information, and partnership. Conclusion: We observed that PEP is an underused HIV prevention strategy among MSM and that once MSM become aware of PEP, the majority are willing to use it if they are supported appropriately in terms of a range of individual, social, and structural barriers. Systematic Review Registration: http://www.cdr.york.ac.uk/prospero, PROSPERO [CRD42019123815].

Characterization of subtypes and transmitted drug resistance strains of HIV among Beijing residents between 2001-2016.

BACKGROUND: Beijing is a national and international hub potentially containing a broad diversity of HIV variants. Previous studies on molecular epidemiology of HIV in Beijing pooled together samples from residents and non-residents. Pooling residents and non-residents has potentially introduced bias and undermined a good assessment and the intervention among the autochthonous population. Here, we aimed to define HIV subtype diversity and investigate the TDR in Beijing residents exclusively. METHODS: We analyzed the demographic, clinical, and virological data collected between 2001 and 2016 from residents in Beijing. A population-based sequencing of the HIV pol gene was carried out using plasma specimens. Phylogenetic analysis was performed in order to classify sequences into their corresponding subtypes using an automated subtyping tool, the Context-Based Modeling for Expeditious Typing (COMET). Furthermore, the drug resistance mutations were determined using the World Health Organization list for surveillance of TDR mutations. RESULTS: Data on TDR were available for 92% of 2,315 individuals with HIV infection, of whom 7.1% were women. The bioinformatic analysis of HIV strains from this study revealed that a combined 17 subtypes were circulating in Beijing, China between 2001 and 2016. The most common ones were CRF01_AE, CRF07_BC, and subtype B in Beijing during this period. The overall prevalence of TDR was 4.5% (95% confidence intervals[CI]: 3.6%-5.4%), with a declining trend over the period of spanning 2001 through 2016. In-depth class-specific analysis revealed that the prevalence of TDR for the nucleoside reverse-transcriptase inhibitors (NRTIs) was 1.0% (95% CI: 0.6-1.5), 0.9% (95% CI:0.6-1.4) for non-NRTIs and 2.8% (95% CI:2.1-3.5) for protease inhibitors. The prevalence of TDR was lower in individuals infected with the CRF07_BC HIV strain than those infected with CRF01_AE. CONCLUSIONS: Our data showed that the HIV epidemic in Beijing displayed a high genetic heterogeneity and a low and declining prevalence of TDR. In sharp contrast to Europe and North America, the declining trend of TDR between 2001 through 2016 was noticed while there was a widespread distribution of antiretroviral treatment in Beijing, China.

Transmitted HIV drug resistance among individuals with newly diagnosed HIV infection: a multicenter observational study.

OBJECTIVES: Fifteen years after the roll-out of antiretroviral treatment (ART) in China, there is limited information available on transmitted HIV drug resistance (TDR). This study aimed to characterize the epidemiology of TDR in China. DESIGN: We conducted a prospective cross-sectional observational study. METHODS: We analyzed the demographic, clinical, and virological data of individuals with newly diagnosed HIV infection using data from the Beijing HIV laboratory network collected between 2001 and 2017. We did population-based sequencing of the pol gene on plasma specimens and identified TDR mutations using the WHO list for surveillance of TDR mutations. RESULTS: Data on TDR were available for 91% of the 10 115 individuals with newly diagnosed HIV infection tested, of whom 19.2% were from rural areas. The overall prevalence of TDR was 4.1% [95% confidence interval (CI): 3.7-4.5%], with a declining trend over the period 2001-2017. In the multivariable analysis, the risk of TDR differed significantly according to sex [odds ratio (OR) for women vs. men: 0.41, 95% CI: 0.22-0.69, P = 0.002]; infection type (OR for CRF07_BC vs. CRF01_AE: 0.24, 95% CI: 0.16-0.36, P < 0.001); and sampling period (OR for 2009-2012 vs. 2001-2008: 0.57, 95% CI: 0.41-0.79; P = 0.01), and was significantly higher among individuals from Hebei province than in those from Beijing (OR: 1.43, 95% CI: 1.05-1.96; P = 0.02). CONCLUSION: In China, the prevalence of TDR among individuals with newly diagnosed HIV infection is relatively low. Trends in TDR should be assessed in other countries with a high TDR burden.

Identification of a Novel HIV-1 Second-Generation Recombinant Form (CRF01_AE/07_BC) in Men Who Have Sex with Men in Beijing, China.

HIV-1 CRF01_AE and CRF07_BC have been two mainly circulating HIV-1 strains in the men who have sex with men (MSM) population in Beijing for years. These two subtypes together were accounting for 78.1% of HIV-1 positive cases newly diagnosed in Beijing, 2016. In this study, we report a novel CRF01_AE/CRF07_BC second-generation unique recombinant form (URF) (named DT1427_NFLG) of HIV-1 identified in MSM population. The near full-length genome of DT1427_NFLG is about 8.8 kb with four CRF07_BC fragments inserted into the CRF01_AE backbone. In China, several novel second-generation URFs were reported in recent years and Beijing, as the capital of China, attracting a huge number of people all over the country to work and live, is confronted with the risk of the epidemic of recombinant HIV-1 strains. Therefore, it is necessary to take measures to monitor the emergency of novel recombinant of HIV-1.

[Viral load test conducive to excluding negative subjects from suspects in HIV antibody detections].

OBJECTIVE: To study whether plasma viral load testing is helpful to exclude ones free from Human immunodeficiency virus (HIV) infections from suspects in HIV antibody detections. METHODS: 19 Specimens, which showed disconcordant results of the two HIV EIA testing (S/CO < 6) and indeterminated results of Western blot (WB) test, were selected. Viral load of the specimens were detected. A six-month follow up survey in detecting HIV antibody was conducted in these subjects. RESULTS: None of these 19 cases was observed to be positive HIV viral loads and there was no any progress in WB bands development during the follow-up period. The possibility of HIV infection could be excluded. CONCLUSION: When the specimens react with very low intensity in both EIA and WB, negative viral load result is conducive to exclude negative subjects from suspects in HIV antibody detections.

Field evaluation of alternative testing strategies for the detection of HIV infection in Beijing.

OBJECTIVE: To identify a cost-efficient alternative antibody testing strategy for screening and confirmation of HIV infection by rapid simple tests (RSTs) and enzyme-linked immunosorbent assays (ELISAs). METHODS: Four RSTs (RST1, RST2, RST3, and RST4) and five ELISAs (ELISA1, ELISA2, ELISA3, ELISA4, and ELISA5) were evaluated in two phases by using banked and serum specimens prospectively collected at regional hospitals and voluntary counseling and testing (VCT) centers in Beijing. A total of 200 banked serum specimens were included in the first phase, including 62 HIV-positive, 127 HIV-negative and 11 indeterminate specimens. All specimens were tested by four RSTs and five ELISAs respectively. The second phase involved prospective testing of 389 routine specimens, including 92 HIV-positive, 287 HIV-negative, and 10 indeterminate specimens. All the specimens were tested by two RSTs (RST2 and RST4) and three ELISAs (ELISA1, ELISA3, and ELISA4), which were selected for their respective excellent sensitivity and/or specificity. Western blot (WB) was used as a gold standard for confirming the reactivity of all the specimens. RESULTS: Sensitivity, specificity, and efficacy were calculated for each assay in two phases. In the first phase, four assays (ELISA4, RST2, RST3, and RST4) had a specificity of 100%. For the determination of efficacy, ELISA4, RST2, and RST4 were selected in the second phase. ELISA1 and ELISA3 which have a sensitivity of 95.9% and 93.2% respectively also entered this phase. In the second phase, all the five assays (ELISA1, ELISA3, ELISA4, RST2, and RST4) had a sensitivity and specifity of over 90%. ELISA1 had a sensitivity of 99% and ELISA4 a specificity of 99%. CONCLUSION: The sensitivity ELISA1 and the specificit of ELISA4 are comparable to ELISA/WB standard strategy. Application of this alternative testing strategy provides a cost-effective method for determining HIV prevalence in Beijing.

A Unique Second-Generation Recombinant Form of HIV-1 Identified Among Men Who Have Sex with Men Population in Beijing, China.

In China, CRF01_AE and CRF07_BC are the most circulating strains of HIV-1, more and more second-generation recombinant forms have been isolated around the two strains. The same situation happened in Beijing in recent years. In our study, we have isolated a new second-generation recombinant form of HIV-1 from a male patient who was infected by homosexual behavior. Polygenetic analysis revealed that the sequence includes five CRF01_AE fragments and four CRF07_BC fragments. CRF01_AE is the skeleton of the recombinant which was inserted with four CRF07_BC fragments. The emergency of such second-generation recombinant forms manifests the diversity of the HIV-1 epidemic. Consequently, further investigation of molecular epidemiology is needed to track the genetic evolution of HIV-1.

Low Rates of Transmitted Drug Resistances Among Treatment-Naive HIV-1-infected Students in Beijing, China.

Beijing has seen a rising epidemic of HIV among students. However, little information was known about the molecular epidemiologic data among HIV-infected students. In this study, the diversity and the prevalence of transmitted drug resistance (TDR) in pol sequences derived from 237 HIV-infected students were analyzed. TDR mutations were found in five men who have sex with men (MSM) population among students. The overall prevalence of TDR in students was 2.1%, comprising 1.3% of protease inhibitors and 0.8% of non-nucleoside reverse transcriptase inhibitors. Our finding indicates a low-level prevalence of TDR mutations among students in Beijing.

Genetic and Phenotypic Analysis of CRF01_AE HIV-1 env Clones from Patients Residing in Beijing, China.

CRF01_AE is one of the four dominant HIV-1 strains circulating in China. In this study, we performed genetic and phenotypic analyses using a total of 60 full-length envelope gene clones from 14 HIV-1-infected individuals in the Beijing area. Among the 60 sequences analyzed, 32 have a complete open reading frame (ORF), whereas the others contain premature stop codons. The phylogenetic tree analysis suggested that all of the sequences maintained a close relationship with the CRF01_AE strain. Most of the potential N-linked glycosylation sites (PNGS) were located within the V1/V2, V4, C2, or C3 regions. In relation to gp41, the majority of the glycosylation sites were located in the ectodomain. The 32 env genes that contained intact ORFs were used to construct Env-pseudotyped viruses, and eight strains that resulted in high titers were further studied. All the eight strains used CCR5 as the co-receptor for infection, and they were sensitive to neutralization by the broadly neutralizing monoclonal antibodies, including VRC_01, PG9, PG16, and NIH45-46, but they were insensitive to 2G12. Notably, seven of these eight strains lacked a glycan at residues 295 or 332 (or both), suggesting that these two PNGSs play an important role in 2G12 binding and neutralization. In addition, the pseudoviruses were more sensitive to neutralization by plasma isolated from individuals infected with subtypes CRF01_AE and CRF07/08_BC, suggesting the occurrence of a cross-neutralizing antibody profile between these two strains. These findings are likely to have important implications for the design of an effective HIV vaccine and relevant therapeutic drugs.

[Molecular epidemiological characteristics of HIV-1 strains isolated from newly diagnosed MSM subjects (2006-2010) in Beijing, China].

This study aims to analyze the molecular epidemiological characteristics of HIV-1 strains prevailing among men who have sex with men (MSM) in Beijing, China. The pol gene fragments from 250 newly diagnosed HIV-1-infected MSM individuals during 2006-2010 in Beijing were amplified by RT-nested PCR, sequenced, and phylogenetically analyzed. HIV-1 pol gene from 189 individuals were amplified and analyzed; 81 (42. 9%), 3 (1. 6%), 2 (1.0%), 88 (46. 6%), and 15 (7.9%) individuals were infected with HIV-1 subtypes B, B', C, CRF01_AE, and CRF07_BC, respectively. The subtypes B and CRF01_AE could both be grouped into two clusters, and CRFO7_BC strains shared high homology and were presumed to originate from a common ancestor. The HIV-1 circulating in MSM in Beijing had a lower genetic diversity than in heterosexuals. The HIV-1 epidemic (2006-2010) in MSM in Beijing was actually a rapid spread of HIV-1 CRF01 AE and B, or rather native strains of the two viruses.

Phylogenetic and temporal dynamics of human immunodeficiency virus type 1B in China: four types of B strains circulate in China.

To investigate the origin and evolutionary history of the spread of HIV-1 subtype B in China, a total of 409 sequences of pol gene sampled from 1994 to 2012 in 29 provinces across China was subjected to phylogenetic and Bayesian molecular clock analyses. The study reveals that subtype B strains in China are genetically diverse and can be classified into four distinct subgroups, namely B' (Thai-B), BJ-B (Beijing-B), Pan-B (Pandemic-B), and TW-B (Taiwan-B), according to the origin of the sequences. The BJ-B and TW-B are reported for the first time. Phylogeographic analysis reveals that B' exhibits a nationwide, transprovincial distribution, and is found in 21 provinces in China in this study, whereas the Pan-B, BJ-B, and TW-B lineages are restricted to particular regions. From the same common ancestor of B', there arise two subclusters in which sequences from Yunnan occupy the basal position. The times of the most recent common ancestors (tMRCAs) of B' and BJ-B are estimated to be 1983.6 (1975.9-1990.3) and 1995.3 (1989.6-2000.3), respectively. The skyline plot profile reveals an exponential decrease in median number of effective infections of subtype B in China from 1994 to 2009. The existence of four types of B clades also indicates distinct transmission networks of subtype B, originating from different introduction events at different time points. The data presented here offer a new perspective on the epidemic of HIV-1 subtype B in China.

[Identification of Env-specific monoclonal antibodies from Chinese HIV-1 infected person by magnetic beads separating B cells and single cell RT-PCR cloning].

OBJECTIVE: To establish a simple and practical method for screening of Env-specific monoclonal antibodies from HIV-1 infected individuals. METHODS: Human B cells were purified by negative sorting from PBMCs and memory B cells were further enriched using anti-CD27 microbeads. Gp120 antigen labbled with biotin was incubated with memory B cells to specifically bind IgG on cells membrane. The memory B cells expressing the Env-specific antibody were harvested by magnetic beads separating, counted and diluted to the level of single cell in each PCR well that loading with catch buffer containing RNase inhibitor to get RNAs. The antibody genes were amplified by single cell RT-PCR and nested PCR, cloned into eukaryotic expression vectors and transfected into 293T cells. The binding activity of recombinant antibodies to Env were tested by ELISA. RESULTS: Three monocolonal Env-specific antibodies were isolated from one HIV-1 infected individual. CONCLUSION: We can obtain Env-specific antibody by biotin labbled antigen, magnetic beads separating technique coupled with single cell RT-PCR and expression cloning.