Emerging HIV Infections With Distinct Subtypes of HIV-1 Infection Among Injection Drug Users From Geographically Separate Locations in Guangxi Province, China:

Rapidly Spreading Human Immunodeficiency Virus Epidemic Among Older Males and Associated Factors: A Large-scale Prospective Cohort Study in Rural Southwest China

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Human immunodeficiency virus incidence was associated with males, older age, less than secondary schooling and not currently being married.

Background

Increasing risk of human immunodeficiency virus (HIV) heterosexual transmission can raise the potential for a more diffuse and generalized epidemic. In response to the paucity of data on HIV incidence among heterosexuals in China, we conducted a large-scale, population-based cohort study located in rural southwest China.

Methods

Baseline enrollment for the study was conducted from 2013 to 2014 and follow-up at 12 months was from 2014 to 2015 among adults 20 years or older in 3 rural counties of Southwest China. Study participants were informed of the study by brochures and leaflets distributed in outreach activities. Interviews and blood collection were conducted in private rooms. Blood samples were tested for HIV infection.

Results

The HIV prevalence of the sample was 0.29% (95% confidence interval [CI], 0.27–0.30) (2063 of 722,795) among the total adult population of 1,090,296 potential participants 20 years or older at baseline. Of the 720,732 individuals who tested HIV-negative at baseline, 493,990 (69%) completed the follow-up. Overall HIV incidence was 2.73 (95% CI, 2.38–3.08) per 10,000 person-years (PY) (235 of 860,627 PY). Human immunodeficiency virus incidence was associated with males, older age, less than secondary schooling and not currently being married. Human immunodeficiency virus incidence was 71.28 (95% CI, 35.21–107.35) per 10,000 PY among males aged 50 to 69 years who had less than secondary schooling and were divorced or widowed. Heterosexual sex was the dominant transmission mode for HIV seroconversions (99.0%).

Conclusions

Older heterosexual males were at disproportionate risk of HIV infection. Health authorities in China need to develop and implement innovative interventions suitable for the broader population of older heterosexuals.

HIV Epidemiology and Prevention in Southwestern China: Trends from 1996-2017

The aim of this review is to describe long-term HIV epidemiology and prevention trends in Guangxi, a provincial-level region located along a major drug trafficking corridor in southwestern China. Between 1996 and 2006, HIV transmission in Guangxi was primarily fueled by Injection Drug Use (IDU). Since 2006, heterosexual sex has become the dominant mode of HIV transmission, followed by drug injection. Moreover, older, heterosexual adults appear to be at increased risk for HIV. The vast majority of new HIV cases are attributed to local HIV subtypes already circulating within Guangxi (93%), though imported subtypes are associated with younger age groups. Since 2011, HIV incidence in Guangxi has stabilized, due in part to HIV prevention efforts that include expanded HIV testing, antiretroviral treatment, and other intervention measures. Between 1996 and 2017, Guangxi, China experienced dramatic changes in the primary HIV transmission mode and at-risk age group. Due in part to local and National AIDS control and prevention campaigns, HIV incidence trends in Guangxi no longer appear to be increasing.

Genomic Characterization of a Novel HIV Type 1 Strain Originating from CRF07_BC and CRF01_AE by Heterosexual Transmission in the Lingshan Prefecture of Guangxi Province, China

Recently, an increasing number of circulating recombinant forms (CRFs) and unique recombinant forms of HIV-1 have been identified in China, contributing substantially to the genetic variability of this virus. This study reports a novel second-generation recombinant form of HIV-1 (GX2015QZLS204), composed of segments from the CRF07_BC and CRF01_AE strains, which was isolated from an HIV-positive male individual infected through heterosexual contact, while residing in the Guangxi province of southwest China. Analysis of the near full-length genome sequence showed that one segment of the CRF01_AE virus subtype was inserted into the CRF07_BC subtype backbone. Recombination analysis demonstrated that the genome of GX2015QZLS204 was separated into seven segments with six breakpoints. Subregion trees constructed by the neighbor-joining method confirmed that the CRF01_AE segment was from the previously identified CRF01_AE cluster 2, and the CRF07_BC segment correlated with the CRF07_BC strain originating from the Jiangxi and Xinjiang provinces of China. The emergence of GX2015QZLS204 highlights the frequent generation of novel recombinant forms and the increasing complications of the HIV-1 epidemic among heterosexual transmission (HET) groups in China. This highlights the importance of monitoring HIV-1 molecular epidemiological characteristics and the urgent need for reduction of the HIV-1 epidemic among HET groups in China.

Characterization of a Novel HIV-1 CRF01_AE/CRF07_BC Recombinant Virus Among Men Who Have Sex with Men in Tianjin, China

We report here a novel human immunodeficiency virus type 1 (HIV-1) second-generation recombinant form comprising CRF01_AE and CRF07_BC isolated from an HIV-positive male subject infected among men who have sex with men (MSM) in Tianjin in north China. The phylogenetic analysis of the near full-length genome of TJIH0345 reveals that three regions of CRF01_AE were inserted into the CRF07_BC backbone with five recombinant breakpoints observed in the pol, vif, vpu, and env gene regions whose genome structure is distinctly different from other circulating recombinant forms and unique recombinant forms previously reported. The continued emergence of the novel recombinant strain in Tianjin, China, highlights the increasing complexity of the HIV-1 epidemic among the MSM population, and further molecular epidemiological investigation should be done to track the genetic evolution of HIV-1 strains to prevent HIV transmission.

Methadone maintenance-lessons from two systems in China

In Hong Kong, methadone maintenance treatment (MMT) was launched in the 1970s, almost 30 years before the counterpart programme’s inauguration in Mainland China. Both were established in response to perceived public crises—addiction-related crime and HIV outbreak, respectively—and both are now regular services under two systems in the same country. Effectiveness of MMT in achieving the stated goals was evident in each case and provides useful lessons on strategies for dealing with the varied concerns related to illicit drug use. Today, with changing patterns of drug addiction, increasing competition for resources, and changing attitudes towards addiction and its treatment, the two MMT systems are confronted with similar challenges to achieve sustainability.

Genetic Characteristics of CRF01_AE Among Newly Diagnosed HIV-1-Infected 16- to 25-Year Olds in 3 Geographic Regions of Guangxi, China

The aim of this study was to analyze the distribution of clusters and drug resistance of CRF01_AE among newly diagnosed, treatment-naïve HIV-infected teenagers and young adults in 3 major HIV-affected geographic regions of Guangxi Province, including the cities of Hezhou, Liuzhou, and Nanning. Samples were sequentially collected from newly diagnosed HIV-infected 16- to 25-year olds in these 3 regions from 2009 to 2013. The viral genome was extracted, and the partial pol gene was amplified and sequenced. Phylogenetic analyses were used to determine HIV-1 subtypes and CRF01_AE clusters. Transmitted drug resistance (TDR) mutations were identified using the 2009 WHO list of TDR mutations. A total of 216 sequences were obtained from CRF01_AE strains, which accounted for 83.1% of the 260 genotyped samples, of which 36 were from Hezhou, 147 from Liuzhou, and 33 in Nanning. Most (83.3%, 180/216) were from heterosexuals, followed by injection drug users (5.6%), homosexuals (4.2%), and unknown risk group (6.9%). Based on phylogenetic analyses by the maximum likelihood method, 5 distinct clusters (cluster 1-5) were identified with 213 (98.6%) sequences, whereas 3 (1.4%) sequences were ungrouped. In Hezhou, 88.9% (32/36) of CRF01_AE infections were caused by cluster 2, and 11.1% (4/36) were caused by cluster 1. In Liuzhou, 83.0% (122/147) of the CRF01_AE strains were found in cluster 1, 11.6% (17/147) from cluster 2, 1.4% (2/147) from cluster 3, 2.7% (4/147) from cluster 4, and 0.7% (1/147) from cluster 5. The distribution of CRF01_AE clusters was more even in Nanning than it was in the other 2 regions, with 18.2% (6/33) from cluster 1, 36.3% (12/33) from cluster 2, 9.1% (3/33) from cluster 3, 18.2% (6/33) from cluster 4, and 12.1% (4/33) from cluster 5. The most frequent TDR mutations were M46I (2) in the protease region and Y181C (2) from the reverse transcriptase fragment. Clusters 1 and 2 of CRF01_AE strains were prevalent in Liuzhou and Hezhou, respectively. However, multiple CRF01_AE clusters existed in Nanning. This can be partially explained by the high mobility of laborers in Nanning, the capital city of Guangxi. The prevalence of TDR was low.

Review of HIV and HCV infection among drug users in China

PURPOSE OF REVIEW

Drug abuse has resulted in a huge public health and economic burden in China, especially the rapid spread of HIV/AIDS and hepatitis C virus (HCV) infection. Multiple HIV and HCV subtypes were detected among drug users in China, this study reviews the molecular distribution of HIV and HCV among injection drug users (IDUs) and explores new epidemiologic trends of HIV and HCV among drug users in China.

RECENT FINDINGS

The 2009 National Narcotic Control Commission report showed that the percentage of users of 'new-type drugs', including amphetamine-type stimulants (ATS: methamphetamine and MDMA/ecstasy) and ketamine, was about 27% of total drug users. The pooled data from published papers showed that CRF07BC was the predominant HIV-1 subtype, which accounted for 38.8%, and it was followed by AE, which accounted for 22.7% among HIV-positive IDUs. Following these, the CRF08BC, B' and C subtypes accounted for about 10.8%, 9.9% and 9.2%, respectively. Subtype 6a was the predominant HCV subtype, accounting for 36.7%, and subtypes 3b, 1a, 3a and 1b were the next most predominant subtypes.

SUMMARY

With the increase of 'new-type drugs' use and AE HIV-1 subtype infection among IDUs, the situation regarding HIV/AIDS and HCV infection has become complicated. More comprehensive prevention and intervention strategies should be instigated for the extensive high-risk populations in China.

Genetic and epidemiologic characterization of HIV-1 infection In Liaoning Province, China

BACKGROUND

Although many studies of HIV-1 in China have focused on high-risk injecting drug users and former blood donors in high prevalence regions, little is known about HIV-1 in relatively low prevalence provinces. Here, we compare the epidemiologic and genetic profile of HIV-1 in Liaoning-a low prevalence province-with those identified in China's most severely affected provinces.

MATERIALS AND METHODS

Two hundred eight HIV-1-positive subjects from all major cities in Liaoning province were recruited between 2000 and 2008. 2.6 kilobase gag-pol sequences were amplified from plasma viral RNA and sequenced directly. The HIV-1 sequences obtained were analyzed using phylogenetic and recombinant approaches.

RESULTS

We have shown that in recent years, although HIV-1 prevalence in Liaoning has remained low, the rate of new infection has increased rapidly, particularly among men who have sex with men and heterosexual risk individuals (together comprising >54% of infected individuals in 2007). Furthermore, phylogenetic analysis has identified all major subtypes/circulating recombinant forms of HIV-1 in Liaoning previously identified in high prevalence provinces. Our study also shows close relationships between HIV-1 subtype/circulating recombinant form and certain risk behaviors. Notably, men who have sex with men and heterosexual risk individuals harbor most divergent strains of HIV-1 from multiple high-risk groups.

CONCLUSIONS

Our study suggested that HIV-1 continues to spread to the general population through sexual contact; Liaoning, therefore, serves as the critical base for the introduction and spread of HIV-1 in northeast China. We believe the transmission patterns suggested herein will help guide public health workers in reducing further spread of HIV-1 within China.

Profile of HIV type 1 infection and genotypic resistance mutations to antiretroviral drugs in treatment-naive HIV type 1-infected individuals in Hai Phong, Viet Nam

We evaluated the prevalence and profile of antiretroviral treatment (ART)-associated resistance mutations among HIV-1 strains in northern Vietnam by genotypically analyzing strains isolated from ART-naive individuals in Hai Phong, a city in which HIV-1 is highly prevalent. Plasma samples were collected from injecting drug users (IDU, n = 760), female sex workers (FSW, n = 91), seafarers (n = 94), pregnant women (n = 200), and blood donors (n = 210), and screened for HIV-1 antibodies. Plasma viral RNA was extracted from HIV-1-positive samples, amplified by reverse transcriptase (RT)-PCR of protease and RT genes, and analyzed for genotypes and ART-associated resistance mutations. HIV-1 prevalence among IDU, FSW, seafarers, pregnant women, and blood donors was 35.9%, 23.1%, 0%, 0.5%, and 2.9%, respectively. Phylogenetic analyses revealed that the most prevalent HIV-1 subtype was CRF01_AE (98.3%), similar to strains prevalent in southern China. Four (1.4%) subtype B strains and one (0.3%) unique recombinant between subtypes B and C were also identified. We found protease inhibitor-associated major resistance mutations in one of the 294 cases analyzed (0.3%; mutation M46I). We found RT inhibitor-associated major resistance mutations in 7/273 cases (2.6%; one occurrence each of L74I, M184I, and K219E; three cases of K103N; and two cases of G190E). One CRF01_AE strain harboring a protease codon 35 insertion was first identified in Vietnam. Thus, monitoring of drug-resistant HIV-1 and establishment of a database are required for the proper selection of ART in Vietnam.

The epidemic origin and molecular properties of B': a founder strain of the HIV-1 transmission in Asia

OBJECTIVE

To clarify the epidemic origin and molecular properties of the B' subtype that is an important strain in the HIV-1 epidemic in Asia.

DESIGN

The genealogical relationship between the B' and B subtype was investigated with two globally representative datasets covering the gag and env regions. B' sequences were identified, from which the epidemic origin, population genetics and the signature mutation sites of the B' subtype were inferred.

METHODS

Two globally representative datasets were compiled, using phylogenetic methods. Through coalescent-based analysis, the genealogical relationship between the B' and B subtypes was investigated. The divergence times and population genetic parameters of B' were estimated in a Bayesian framework using Markov Chains Monte Carlo sampling under a relaxed molecular clock method. Additionally, molecular properties of the B' were identified by performing comparative sequence analysis with the HIV-1 M group.

RESULTS

About 15 years later after the B subtype began to spread, the B' diverged from the B subtype. The demographic history of B' was reconstructed, and the epidemic of B' was estimated to originate around 1985. Eight and nine distinct signature mutation sites, unique to B', were found around the p17 and V3 regions, respectively.

CONCLUSION

Our research is the first large-scale investigation on HIV-1 B' at a global level and provides a deep insight into one of the founder strains of HIV-1 epidemic in Asia. Our results provide an important reference for HIV scientists, public health officials and HIV vaccine designers.

New challenges for mathematical and statistical modeling of HIV and hepatitis C virus in injecting drug users

Injecting drug users are not only driving blood-borne transmission of HIV and hepatitis C virus but also likely drive sexual transmission of HIV in large parts of the world. Mathematical and statistical modeling can provide important insights in these epidemiological processes and on the potential impact of interventions but have been little used to date. This review aims to discuss the potential areas of application of modeling in the field of viral infections in injecting drug users. After reviewing key examples of published modeling work on HIV and hepatitis C virus in injecting drug users, we discuss recent developments in the epidemiology, diagnosis, treatment and prevention of these infections. In particular, new methods for the diagnosis of early HIV infection, new antivirals for a more effective treatment of HIV, hepatitis B and hepatitis C virus infections, new concepts in design and surveillance of interventions for drug users and increasing possibilities of molecular typing of pathogens are changing the questions and decisions for public health policy makers who deal with drug-related infectious diseases. Research including mathematical modeling is needed to understand the impact of new diagnostic tools, new treatment options and combined intervention strategies on the epidemiology of viral infections in injecting drug users. Methodological advances in mathematical modeling are required to adequately approach some of the ensuing research questions. Modeling has much to offer for solving urgent policy questions, but current levels of funding in modeling research are insufficient and need to be scaled up to make better use of these possibilities.

Design, construction, and characterization of a multigenic modified vaccinia Ankara candidate vaccine against human immunodeficiency virus type 1 subtype C/B'

The rapid spread of HIV-1 underscores the urgent need to develop an effective vaccine. Using modified vaccinia Ankara (MVA) as a vector, we designed and constructed a multigenic candidate vaccine against a recombinant C/B' subtype of HIV-1 that is dominant in southwest China. Five HIV-1 genes (gag, pol, DeltaV2env, tat, and nef) were introduced into 2 separate regions of the MVA genome using modified single- and dual-promoter insertion vectors. Recombinant MVA was selected by immunofluorescence double-staining and foci purification. The end product is a single recombinant MVA, termed ADMVA, that expresses HIV-1 DeltaV2Env and fusion proteins Gag-Pol and Nef-Tat. By in vitro analyses, all expected HIV-1 proteins were expressed in infected chicken embryo fibroblasts and various human cell lines. Additionally, 2 sequential intramuscular injections of 10(6) 50% tissue infectious culture dose (TCID50) of ADMVA into BALB/c and B6 x B10 mice elicited broad cell-mediated immune responses against all 5 viral proteins as determined by interferon-gamma enzyme immunospot assays. The number of spot-forming cells was in the range of 200 to 800 per million splenocytes, and both CD4 and CD8 T-cell responses were detected. Moreover, high serum titers (>1:20,000) of antibodies against HIV-1 gp120 were also elicited. The magnitude of immune responses correlated with the dose of ADMVA, and the vaccine caused no overt adverse consequences, up to 10(7) TCID50 per injection. ADMVA has since been advanced into clinical trials. A phase 1 study has been completed, and a prime-boost with ADVAX (see accompanying article) is now underway.

An Epidemic of HIV Type I CRF07_BC Infection Among Injection Drug Users in Taiwan

The human immunodeficiency virus type 1 (HIV-1) epidemic in Taiwan is rapidly escalating because of an increasing number of injection drug users (IDUs). A molecular epidemiological study of HIV-1-infected IDUs in Taiwan was conducted from January 2004 to April 2005. Of the 131 HIV-1-positive specimens collected, all contained detectable sequences, including 105 from the C2-V3 region of env and 87 from the protease and reverse transcriptase genes of pol. Phylogenetic analysis of these sequences indicated that 128 individuals harbored CRF07_BC, which resembles the dominant strains circulating among IDUs in China. Twenty-three individuals had a history of travel to the southwest provinces of China and shared needles or apparatuses there. This suggests that CRF07_BC might have been transmitted from China into Taiwan, thereby causing an outbreak among IDUs in Taiwan. This is the first report in the English literature of the appearance of HIV-1 CRF07_BC in Taiwan. These provide information relevant to the development of antiviral therapy and vaccine in Taiwan and may assist public health workers in the prevention of HIV-1 spread.

High HIV prevalence and risk factors among injection drug users in Tashkent, Uzbekistan, 2003-2004

OBJECTIVES

To determine HIV prevalence and potential associations with sociodemographic and behavioral factors among injection drug users (IDUs) in Tashkent, Uzbekistan.

METHODS

Subjects in this cross-sectional study provided sociodemographic and risk behavior data and were tested for HIV antibody with a saliva-based enzyme-linked immunosorbent assay (ELISA), followed by saliva-based Western blot confirmation.

RESULTS

Among the 701 IDU subjects enrolled, 209 (29.8%) were diagnosed with HIV infection, HIV infection was more likely among those unemployed (adjusted odds ratio [AOR]=1.47); whose first drug of abuse was heroin (AOR=2.21) or opium poppy extract (AOR=1.61); with a prior history of hepatitis (AOR=1.39); and those who reported never using condoms (AOR=1.65). Independent risk factors associated with HIV infection were heroin as the first illicit drug of abuse, prior hepatitis, lack of condom use, and unemployment.

CONCLUSIONS

Heroin use, sexual transmission, and high unemployment seem to play important roles in HIV transmission. Implementation of effective harm reduction strategies is critical to control the expansion of the HIV epidemic in this country as well as in this region.

Heterosexual Transmission of HIV in China: A Systematic Review of Behavioral Studies in the Past Two Decades

OBJECTIVE

The objective of this study was to address the role of heterosexual transmission of HIV in China.

GOAL

The goal of this study was to explore the prevalence of unsafe sex and the likelihood of HIV spread heterosexually from core populations to others.

STUDY

The authors conducted a review of behavioral studies.

RESULTS

Drug users were more likely to be involved in higher-risk sexual behaviors than were those who abstained from using drugs. Most female drug users (52-98%) reported having engaged in commercial sex. Most female sex workers (FSWs) and individuals with sexually transmitted diseases (STDs) had concurrent sexual partners. Many continued to have unprotected sex after noticing STD symptoms in themselves or their sexual partners. From 5% to 26% of rural-to-urban migrants had multiple sexual partners and 10% of males patronized FSWs during migration.

CONCLUSIONS

Factors such as high rates of FSW patronage, low rates of condom use during commercial sex, having sex with both commercial and noncommercial sexual partners, and high rates of STD infection may promote a heterosexual epidemic in China.

Correlates of HIV status among injection drug users in a border region of southern China and northern Vietnam

This article presents an analysis of the correlates of HIV status among samples of injection drug users (IDUs) in Lang Son Province, Vietnam (n=348), and Ning Ming County, Guangxi Province, China (n=294), who were interviewed and tested for HIV antibody just before the start of a peer-based HIV prevention intervention in this border region. Participants were largely male, in their 20s, and single. Logistic regression analysis suggests that among Chinese IDUs, border-related factors (eg, living closer to the border, buying drugs across the border more frequently) and younger age are the best predictors of HIV positivity. In Vietnam, HIV status seems to drive behavior (eg, some risk reduction practices are predictive of HIV positivity). These differing patterns may reflect the fact that the intertwined epidemics of heroin injection and HIV began earlier and HIV prevalence has reached significantly higher levels in Lang Son than across the border in Ning Ming. Although border-related factors emerge as predictors in Ning Ming, more IDUs in Lang Son are HIV-positive and may be reacting behaviorally to that status. Their greater likelihood of engaging in risk reduction measures may reflect some combination of a belief that risk reduction can slow disease progression and an altruistic desire to avoid infecting others.

HIV-1 infection among injection and ex-injection drug users from Rio de Janeiro, Brazil: prevalence, estimated incidence and genetic diversity

BACKGROUND AND OBJECTIVES

Due to their behavioral conditions and vulnerability, injection drug users (IDUs) are prone to multiple simultaneous or sequential infections with distinct HIV-1 subtypes and variants, making them a key population for molecular epidemiology surveillance. In the present study, we evaluated HIV-1 infection seroprevalence, genetic diversity and estimated incidence among IDUs and ex-injection drug users (ex-IDUs) from Rio de Janeiro, Brazil.

STUDY DESIGN

Six hundred and eight IDUs and ex-IDUs, recruited between 1999 and 2001, were interviewed and agreed to donate 30 ml of blood. The serologic status for HIV infection was determined by two ELISAs and confirmed by IFA. CD4+ T-cell percentages were assessed by flow cytometry. HIV-1 positive samples were submitted to viral load quantification. DNA samples were PCR amplified and HIV-1 subtypes were determined using env and gag HMA.

RESULTS AND CONCLUSIONS

Forty-eight (7.89%) individuals were seropositive for HIV-1 infection. The seroincidence of HIV-1 infection was estimated as 0.76%. HIV-1 env and gag subtyping identified 29 (69%) samples as belonging to subtype B, 7 (16.7%) to subtype F, and 6 (14.3%) discordant env/gag genomes infections, indicating the circulation of recombinant viruses in this population.

HIV-1 subtype B' dictates the AIDS epidemic among paid blood donors in the Henan and Hubei provinces of China

OBJECTIVE

To investigate the genetic background of HIV-1 strains among infected paid blood donors (PBD) in the Henan and Hubei provinces of China.

METHODS

The polymerase chain reaction was used to amplify HIV-1 gag p17 fragments and some 5'-half or full-length viral genomes from peripheral blood mononuclear cells. The HIV-1 sequences obtained were analysed using phylogenetic and recombinant approaches.

RESULTS

Among the total of 62 samples studied, 59 (95.2%) came from PBD. Of those 59 PBD, 45 were collected from 14 different geographical locations in Henan, whereas the remaining 14 were from five locations in Hubei. A total of 62 HIV-1 gag p17 fragments, three 5'-half and one full HIV-1 genome sequences were obtained. Phylogenetic analysis of these sequences suggests that PBD from Henan and Hubei, despite being geographically distant, harbored a group of genetically closely related HIV-1 B' strains. No recombinant forms have been detected in this cohort.

CONCLUSION

Our data indicate that the AIDS epidemic among PBD in Henan and Hubei is caused largely by HIV-1 subtype B', which contrasts greatly with the CB' recombinant strains CRF-07 and CRF-08 currently dominating among the drug abusers in other regions of China. Our report has revealed the first complete genome background of the most dominant circulating HIV-1 strain in Henan and Hubei, which is essential for the design and development of an effective AIDS vaccine for the region.

Cytotoxic T-cell recognition of HIV-1 cross-clade and clade-specific epitopes in HIV-1-infected Thai and Japanese patients

OBJECTIVE

To identify and characterize cytotoxic T-cell (CTL) epitopes for HIV-1 clade E using eight known HLA-A*1101-restricted HIV-1 clade B epitopes.

METHODS

Induction of clade E-specific CTL was examined by stimulating peripheral blood mononuclear cells (PBMC) from clade E-infected Thai individuals with the clade E-specific peptide corresponding to the clade B epitopes. Cross-clade and clade-specific CTL recognition for these epitopes was analysed using CTL clones and bulk CTL specific for these epitopes. To clarify the presentation of these epitopes in HIV-1-infected T cells, CTL recognition for the clade E-specific and cross-clade epitopes was investigated using CD4CXCR4 cells infected with an HIV-1 clade E clone.

RESULTS

Three epitopes, which are identical among clades A-E, were recognized as cross-clade CTL epitopes in both individuals. Clade B and E sequences corresponding to three epitopes were recognized as clade-specific epitopes in clade B-infected and clade E-infected individuals, respectively. In contrast, clade E-specific peptides corresponding to two other clade B epitopes failed to elicit clade E-specific CTL. CTL specific for the three cross-clade and three clade E-specific epitopes effectively lysed target cells infected with HIV-1 clade E virus.

CONCLUSIONS

These six epitopes are found to be processed naturally in HIV-1 clade E-infected cells. We show here that a strategy utilizing HIV-1 clade B epitopes is very useful for identifying clade E CTL epitopes.

Maintaining low HIV type 1 env genetic diversity among injection drug users infected with a B/C recombinant and CRF01_AE HIV type 1 in southern China

HIV-1 outbreaks in Guangxi Province, southern China were initiated from two separate border cities in 1996 and 1997. Drug users in Pingxiang City, which borders Vietnam, were infected with CRF01_AE HIV-1, and drug users in Baise City, which borders Yunan Province, were infected with a novel B/C recombinant HIV-1. Since 1997, HIV-1 has been rapidly spreading in Guangxi, including its capital city Nanning. Survey data indicated that HIV-1 prevalence among IDUs in new outbreak regions increased 8 to 42% within 1 year. The B/C recombinants obtained from five separate regions in Guangxi, which span a 4-year time frame, were remarkable for their low intersubject env V3 diversity, less than 0.2%. Similarly, the CRF01_AE from IDUs over a 3-year time frame had low intersubject env V3 diversity of less than 1.6%. Different patterns of sequence variations in the V3 and V4 regions were observed for the B/C recombinant and the CRF01_AE HIV1. The rapid spreading of homogeneous HIV-1 strains in Guangxi may have important implications for HIV transmission as well as vaccine development and evaluation.

High proportion of unrelated HIV-1 intersubtype recombinants in the Mbeya region of southwest Tanzania

BACKGROUND

In Mbeya, a rural region of southwest Tanzania, HIV-1 subtypes A, C and D have been co-circulating since the early 1990s.

OBJECTIVE

To define to what extent the co-existence of subtypes has led to recombinant HIV-1 strains and whether there is evidence for epidemic spread of any circulating recombinant form.

METHODS

Nine HIV-1-seropositive young adults from Mbeya Town with no evident high-risk behaviour contributed peripheral blood mononuclear cells for this study. Nine virtually full-length-genome-sequences were amplified from this DNA and phylogenetically analysed.

RESULTS

Out of the nine samples, two were subtype A (22%), two were subtype C (22%) and five were recombinants (56%): four A/C recombinants and one C/D recombinant. None of the recombinants were related to each other; all of them had different mosaic structures. Most of the genome in the recombinants was subtype C.

CONCLUSION

A high proportion of unrelated intersubtype recombinants, none of them apparently spreading in the population, may be present in southwest Tanzania.

Closely related HIV-1 CRF01_AE variant among injecting drug users in northern Vietnam: evidence of HIV spread across the Vietnam-China border

To investigate the nature of recent HIV outbreaks among injecting drug users (IDUs) near the Vietnam-China border, we genetically analyzed 24 HIV-positive blood specimens from 2 northern provinces of Vietnam (Lang Son and quang Ninh) adjacent to the China border, where HIV outbreaks among IDUs were first detected in late 1996. Genetic subtyping based on gag (p17) and env (C2/V3) sequences revealed that CRF01_AE is a principal strain circulating throughout Vietnam, including the provinces near the China border. The majority of CRF01_AE sequences among IDUs in Quang Ninh and Lang Son showed significant clustering with those found in nearby Pingxiang City of China's Guangxi Province, sharing a unique valine substitution 12 amino acids downstream of the V3 loop. This particular subtype E variant, uniquely found among IDUs in northern Vietnam and southeastern China, is designated E(v). The genetic diversity of CRF01_AE distributed in Quang Ninh (1.5 +/- 0.6%) and Pingxiang City (1.9 +/- 1.2%) was remarkably low, indicating the emerging nature of HIV spread in these areas. It is also noted that the genetic diversity of CRF01_AE among IDUs was consistently lower than that in persons infected sexually, suggesting that fewer closely related CRF01_AE variants were introduced into IDUs and, conversely, that multiple strains of CRF01_AE had been introduced via the sexual route. The data in the present study provide additional evidence that HIV outbreaks among IDUs in northern Vietnam were caused by the recent introduction of a highly homogeneous CRF01_AE variant (E(v)) closely related to that prevailing in nearby southern China.