Human immunodeficiency virus type 2 infection in Spain. The HIV-2 Spanish Study Group

Genetic Variability of Long Terminal Repeat Region between HIV-2 Groups Impacts Transcriptional Activity

The HIV-2 long terminal repeat (LTR) region contains several transcription factor (TF) binding sites. Efficient LTR transactivation by cellular TF and viral proteins is crucial for HIV-2 reactivation and viral production. Proviral LTRs from 66 antiretroviral-naive HIV-2-infected patients included in the French ANRS HIV-2 CO5 Cohort were sequenced. High genetic variability within the HIV-2 LTR was observed, notably in the U3 subregion, the subregion encompassing most known TF binding sites. Genetic variability was significantly higher in HIV-2 group B than in group A viruses. Notably, all group B viruses lacked the peri-ETS binding site, and 4 group B sequences (11%) also presented a complete deletion of the first Sp1 binding site. The lack of a peri-ETS binding site was responsible for lower transcriptional activity in activated T lymphocytes, while deletion of the first Sp1 binding site lowered basal or Tat-mediated transcriptional activities, depending on the cell line. Interestingly, the HIV-2 cellular reservoir was less frequently quantifiable in patients infected by group B viruses and, when quantifiable, the reservoirs were significantly smaller than in patients infected by group A viruses. Our findings suggest that mutations observed in vivo in HIV-2 LTR sequences are associated with differences in transcriptional activity and may explain the small cellular reservoirs in patients infected by HIV-2 group B, providing new insight into the reduced pathogenicity of HIV-2 infection.IMPORTANCE Over 1 million patients are infected with HIV-2, which is often described as an attenuated retroviral infection. Patients frequently have undetectable viremia and evolve at more slowly toward AIDS than HIV-1-infected patients. Several studies have reported a smaller viral reservoir in peripheral blood mononuclear cells in HIV-2-infected patients than in HIV-1-infected patients, while others have found similar sizes of reservoirs but a reduced amount of cell-associated RNA, suggesting a block in HIV-2 transcription. Recent studies have found associations between mutations within the HIV-1 LTR and reduced transcriptional activities. Until now, mutations within the HIV-2 LTR region have scarcely been studied. We conducted this research to discover if such mutations exist in the HIV-2 LTR and their potential association with the viral reservoir and transcriptional activity. Our study indicates that transcription of HIV-2 group B proviruses may be impaired, which might explain the small viral reservoir observed in patients.

Recombinant viruses initiated the early HIV-1 epidemic in Burkina Faso

We analyzed genetic diversity and phylogenetic relationships among 124 HIV-1 and 19 HIV-2 strains in sera collected in 1986 from patients of the state hospital in Ouagadougou, Burkina Faso. Phylogenetic analysis of the HIV-1 env gp41 region of 65 sequences characterized 37 (56.9%) as CRF06_cpx strains, 25 (38.5%) as CRF02_AG, 2 (3.1%) as CRF09_cpx, and 1 (1.5%) as subtype A. Similarly, phylogenetic analysis of the protease (PR) gene region of 73 sequences identified 52 (71.2%) as CRF06_cpx, 15 (20.5%) as CRF02_AG, 5 (6.8%) as subtype A, and 1 (1.4%) was a unique strain that clustered along the B/D lineage but basal to the node connecting the two lineages. HIV-2 PR or integrase (INT) groups A (n = 17 [89.5%]) and B (n = 2 [10.5%]) were found in both monotypic (n = 11) and heterotypic HIV-1/HIV-2 (n = 8) infections, with few HIV-2 group B infections. Based on limited available sampling, evidence suggests two recombinant viruses, CRF06_cpx and CRF02_AG, appear to have driven the beginning of the mid-1980s HIV-1 epidemic in Burkina Faso.

Molecular phylogenetics of nearly full-length HIV type 2 envelope gene sequences from West India

Abstract While infection with HIV-1 has become a pandemic, the presence of HIV-2 is also of concern in certain regions of the world. We have characterized the gp105 region of the envelope gene of HIV-2 isolates from Western India. Phylogenetic analysis of all 18 sequences revealed that these sequences were closely related to each other as well as to published African and European HIV-2 group A sequences, with an overall genetic divergence of 10.9% (range 2-14%). Our study sequences showed close relatedness with West African HIV-2 group A (CAM group) sequences from Guinea Bissau with 89% homology. This was further confirmed by SimPlot as well as RIP analysis. Accordingly, the sequences presented here demonstrate the predominance of HIV-2 group A infection and show no evidence of HIV-2 recombination in Western India.

Indian primary HIV-2 isolates and relationship between V3 genotype, biological phenotype and coreceptor usage

The chemokine coreceptors play a significant role in HIV entry and pathogenesis. The V3 region of HIV envelope glycoprotein is considered as a principal determinant for viral phenotype and tropism. The present study describes lack of association between the V3 genotype and viral phenotype of 18 Indian HIV-2 isolates. The viruses were isolated, confirmed by PCR and the HIV subtypes were determined by sequencing V3 region of the env gene. The coreceptor usage and syncytium inducing (SI) capacity of isolates was determined. Our study indicated that CCR5 coreceptor usage and NSI phenotype is predominant among Indian HIV-2 isolates obtained from patients in the early stage of infection. Two of the four HIV-2 isolates obtained from the late stage patients were SI and dual tropic. Phylogenetic analysis of these isolates revealed close relatedness to the isolates from western and southern India.

HIV-2 protease sequences of subtypes A and B harbor multiple mutations associated with protease inhibitor resistance in HIV-1

BACKGROUND

HIV-1 protease inhibitors (PI) have been used for treating HIV-2-infected persons but little is known about amino acid mutations associated with PI resistance in HIV-2 and whether they are similar to those seen in HIV-1.

OBJECTIVE

To determine the frequency of HIV-1 PI resistance-associated mutations in PI-naive HIV-2-infected individuals.

DESIGN

Using PCR, protease genes were amplified from 76 individuals, directly sequenced, phylogenetically subtyped, and translated into amino acids to analyze PI-associated major and minor mutations.

RESULTS

Of the 76 HIV-2 sequences, 68% belonged to subtype A and 32% to subtype B. All sequences contained at least four codon changes giving substitutions at 10, 30, 32, 36, 46, 47, 71 or 77. The frequency of these mutations was similar in subtype A and B viruses. Two major resistance-conferring mutations, 30N and 46I, were identified in one (1%) and 68 (89%) specimens, respectively. Minor mutations 10V/I, 32I, 36I, 47V, and 71V were predominant (89%-100%), followed by the rare mutation 77I (1%). Of the 76 strains, 89% harbored multiple PI resistance-associated substitutions comprising both the major 46I and minor mutations: 10V/I, 32I, 36I, 46I, 47V, 71V (76%); 10V, 32I, 36I, 46I, 47V (9%); and 10V, 32I, 36I, 46I, 47V 71V, 77I (1.3%), 10V, 32I, 46I, 47V, 71V (1.3%), and 10V, 30N, 32I, 36I, 46I, 47V, 71V (1.3%). The remaining 11% of the sequences had patterns with only minor mutations: 10V, 32I, 36I, 47V, 71V (9%) and 10V, 32I, 36I, 47V (1.3%).

CONCLUSIONS

The high frequency of multiple PI-associated substitutions represent natural polymorphisms occurring in HIV-2 strains of subtypes A and B. Phenotypic and clinical studies are needed to determine the relevance of these substitutions.

Detection and characterization of HIV type 2 in Calcutta, India

Since the first report of HIV/AIDS in India in 1986, continuous serosurveillance has been undertaken in all Indian states. Recently, five cases of HIV-2 infection have been detected in Calcutta, situated in the eastern part of India. The full-length envelope gene (2.5 kb) of one of the strains was amplified, cloned, and sequenced. Phylogenetic analysis of the Calcutta HIV-2 envelope revealed a close relatedness to the HIV-2 Rod sequence isolated in offshore Senegal. This strain, however, showed a genetic diversity of 13.5% to other Indian HIV-2 isolates.

[Imported diseases in African immigrants in Spain: study of 1,321 patients]

BACKGROUND

Immigrants can carry diseases characteristic from their countries of origin. These are known as imported diseases (ID) and can be classified into tropical diseases (TD) or cosmopolitan diseases (CD). The aim of this study was to analyse the ID in African immigrants and evaluate their repercussion in the Spanish Public Health.

PATIENTS AND METHOD

Observational study, retrospective protocol, carried from 1984 to 1994 in African immigrants seen in a reference Hospital. Not infectious chronic ID were excluded. The repercussion in public health was divided in 3 categories according to transmission risk to the host population: a) ID without current risk; b) ID with potential risk and, c) ID of risk.

RESULTS

1,321 African immigrants were considered. Most of them were from Sub-Saharan Africa. The most frequent TD were helminthiases and among CD, tuberculosis, sexually transmitted diseases and parasitoses. ID without transmission risk were 26.7% (2.4% CD and 24.3% TD), ID with potential risk 35.2% (33.6% CD and 1.6% TD) and ID with risk 38% (all CD).

CONCLUSIONS

The CD and their association with poverty suppose a higher risk of transmission to the host country population. Global policies of helping social and economic insertion of immigrant populations, combined with international health collaboration, will rebound positively in the general population's health.

Molecular evidence of homosexual transmission of HIV type 2 in Spain

Eight HIV-2-infected Caucasian men living in the same geographical area in Gipuzkoa (northern Spain) have been identified in the last 5 years. HIV-2 infection in this area is uncommon, and no other cases of HIV-2 infection have been found after extensive testing for HIV-1/2 antibodies. Epidemiological data suggested a possible link among the identified subjects, with homosexual contact being the most likely way of transmission. A genetic analysis of four of the subjects, from whom specimens were available, was conducted. Phylogenetic and signature pattern studies of the reverse transcriptase (RT) and env genes supported a single source of infection. Interindividual nucleotide variability ranged from 2.4 to 4.8% in the RT region and from 5.2 to 6.1% in the env gene, whereas the mean divergence between patient and control strains was 9.8 and 18.3%, respectively. The nucleotide and amino acid signature patterns were closely related in viruses from the four examined individuals. This is the first report of a cluster of HIV-2 infections with genetic sequence data support. The singularity of this cluster should alert clinicians on the possibility of HIV-2 outside endemic areas.

Development of a real-time quantitative RT-PCR for the detection of HIV-2 RNA in plasma

An assay is described for the quantification of human immunodeficiency virus type 2 (HIV-2) RNA in EDTA plasma based on RT-PCR using the Taqman real-time PCR detection method. As standard, an electron microscopically counted virus stock of HIV-2 strain NIHZ was used. The lower detection limit is 5 # 102 HIV-2 RNA copies per ml of EDTA plasma. The assay is linear within the range required (5 # 102-106 HIV-2 RNA copies/ml of EDTA plasma) with an intra assay variability of 2.5% and an inter-assay variability ranging from 2% at 106 copies to 7.5% at the lower detection limit. Three primer/probe combinations were developed to circumvent false negative samples due to nucleotide variation in the target sequence. Using these primer/probe sets enabled the detection of HIV-2 DNA sequences from all HIV-2 seropositive individuals and two out of five dual human immunodeficiency virus type 1 (HIV-1) and HIV-2 seropositive individuals visiting the University Hospital Rotterdam.