Drug resistance pattern among ART-naive clients attending an HIV testing and counseling center in Dhaka, Bangladesh.

In Bangladesh, antiretroviral therapy (ART) is provided without screening drug resistance-associated mutations (DRM) among people living with HIV, while DRM might emerge and transmit to the newly infected individual. The present study was aimed to identify DRM among ART-naive clients from an HIV testing and counseling (HTC) center in the initial stages of ART programs. Randomly selected (n = 64) archived plasma samples were used for the pol gene amplification and sequencing by sanger technology. Recovered sequences (n = 10) were genotyped using HIV genotyping tools of NCBI and analyzed using the Stanford University HIV drug resistance database (hivdb.stanford.edu). Various genotypes with a number of DRM were identified in HTC clients, who belonged to different risk groups based on behavioral data. The drug resistance algorithm showed that all samples were fully resistant to tipranavir/ritonavir drugs except for one intermediate resistance. Despite the small sample size, our understanding from this study warrants an ART policy with a DRM monitoring system for the country.

High-throughput sequencing reveals a high prevalence of pretreatment HIV-1 drug resistance in Sweden.

OBJECTIVES: HIV-1 pretreatment drug resistance (PDR) is a global concern. Our aim was to evaluate high-throughput sequencing (HTS) for HIV-1 resistance testing and describe PDR in Sweden, where 75% of diagnosed individuals are foreign-born. DESIGN: Cross-sectional study. METHODS: Individuals entering HIV-1 care in Sweden 2017 to March 2019 (n = 400) were included if a viremic sample was available (n = 220). HTS was performed using an in-house assay. Drug resistance mutations (DRMs) (based on Stanford HIV DB vs. 8.7) at levels 1-5%, 5-19% and at least 20% of the viral population were described. Results from HTS and routine Sanger sequencing were compared. RESULTS: HTS was successful in 88% of patients, 92% when viral load was at least 1000 copies/ml. DRMs at any level in protease and/or reverse transcriptase were detected in 95 individuals (49%), whereas DRMs at least 20% in 35 (18%) individuals. DRMs at least 20% correlated well to findings in routine Sanger sequencing. Protease/reverse transcriptase (PR/RT) DRMs at least 20% were predicted by treatment exposure; adjusted OR 9.28 (95% CI 2.24-38.43; P = 0.002) and origin in Asia; adjusted OR 20.65 (95% CI 1.66-256.24; P = 0.02). Nonnucleoside reverse transcriptase inhibitor (NNRTI) DRMs at least 20% were common (16%) and over-represented in individuals originating from sub-Saharan Africa or Asia. Low-level integrase strand transfer inhibitor (INSTI) DRMs less than 20% were detected in 15 individuals (8%) with no association with INSTI exposure. CONCLUSION: Our HTS can efficiently detect PDR and findings of DRMs at least 20% compare well to routine Sanger sequencing. The high prevalence of PDR was because of NNRTI DRMs and associated with migration from areas with emerging PDR.

MiDRMpol: A High-Throughput Multiplexed Amplicon Sequencing Workflow to Quantify HIV-1 Drug Resistance Mutations against Protease, Reverse Transcriptase, and Integrase Inhibitors.

The detection of drug resistance mutations (DRMs) in minor viral populations is of potential clinical importance. However, sophisticated computational infrastructure and competence for analysis of high-throughput sequencing (HTS) data lack at most diagnostic laboratories. Thus, we have proposed a new pipeline, MiDRMpol, to quantify DRM from the HIV-1 pol region. The gag-vpu region of 87 plasma samples from HIV-infected individuals from three cohorts was amplified and sequenced by Illumina HiSeq2500. The sequence reads were adapter-trimmed, followed by analysis using in-house scripts. Samples from Swedish and Ethiopian cohorts were also sequenced by Sanger sequencing. The pipeline was validated against the online tool PASeq (Polymorphism Analysis by Sequencing). Based on an error rate of <1%, a value of >1% was set as reliable to consider a minor variant. Both pipelines detected the mutations in the dominant viral populations, while discrepancies were observed in minor viral populations. In five HIV-1 subtype C samples, minor mutations were detected at the <5% level by MiDRMpol but not by PASeq. MiDRMpol is a computationally as well as labor efficient bioinformatics pipeline for the detection of DRM from HTS data. It identifies minor viral populations (<20%) of DRMs. Our method can be incorporated into large-scale surveillance of HIV-1 DRM.

Antiretroviral potency of 4'-ethnyl-2'-fluoro-2'-deoxyadenosine, tenofovir alafenamide and second-generation NNRTIs across diverse HIV-1 subtypes.

Objectives: 4'-Ethnyl-2'-fluoro-2'-deoxyadenosine (EFdA) is a novel translocation-defective reverse transcriptase inhibitor. We investigated the virological and biochemical inhibitory potentials of EFdA against a broad spectrum of subtype-specific chimeric viruses and compared it with tenofovir alafenamide, nevirapine, efavirenz, rilpivirine and etravirine. Methods: pNL4.3 chimeric viruses encoding gag-pol from treatment-naive patients (n = 24) and therapy-failure patients (n = 3) and a panel of reverse transcriptase inhibitor-resistant strains (n = 7) were used to compare the potency of reverse transcriptase inhibitor drugs. The phenotypic drug susceptibility assay was performed using TZM-bl cells. In vitro inhibition assays were done using patient-derived reverse transcriptase. IC50 values of NNRTIs were calculated using a PicoGreen-based spectrophotometric assay. Steady-state kinetics were used to determine the apparent binding affinity (Km.dNTP) of triphosphate form of EFdA (EFdA-TP) and dATP. Results: Among the chimeric treatment-naive viruses, EFdA had an ex vivo antiretroviral activity [median (IQR) EC50 = 1.4 nM (0.6-2.1 nM)] comparable to that of tenofovir alafenamide [1.6 nM (0.5-3.6 nM)]. Subtype-specific differences were found for etravirine (P = 0.004) and rilpivirine (P = 0.017), where HIV-1C had the highest EC50 values. EFdA had a greater comparative efficiency [calculated by dividing the efficiency of monophosphate form of EFdA (EFdA-MP) incorporation (kcat.EFdA-TP/Km.EFdA-TP) over the efficiency of dATP incorporation (kcat.dATP/Km.dATP)] compared with the natural substrate dATP, with a fold change of between 1.6 and 3.2. Ex vivo analysis on reverse transcriptase inhibitor-resistant strains showed EFdA to have a higher potency. Despite the presence of rilpivirine DRMs, some non-B strains showed hypersusceptibility to rilpivirine. Conclusions: Our combined virological and biochemical data suggest that EFdA inhibits both WT and reverse transcriptase inhibitor-resistant viruses efficiently in a subtype-independent manner. In contrast, HIV-1C is least susceptible to etravirine and rilpivirine.

Coreceptor Tropism and Maraviroc Sensitivity of Clonally Derived Ethiopian HIV-1C Strains Using an in-house Phenotypic Assay and Commonly Used Genotypic Methods.

OBJECTIVES: Genotypic Tropism Testing (GTT) tools are generally developed based on HIV-1 subtype B (HIV-1B) and used for HIV-1C as well but with a large discordance of prediction between different methods. We used an established phenotypic assay for comparison with GTT methods and for the determination of in vitro maraviroc sensitivity of pure R5-tropic and dual-tropic HIV-1C. METHODS: Plasma was obtained from 58 HIV-1C infected Ethiopians. Envgp120 was cloned into a luciferase tagged NL4-3 plasmid. Phenotypic tropism was determined by in house method and the V3 sequences were analysed by five GTT methods. In vitro maraviroc sensitivity of R5-tropic and dual-tropic isolates were compared in the TZMbl cell-line. RESULTS: The phenotypes were classified as R5 in 92.4% and dual tropic (R5X4) in 7.6% of 79 clones. The concordance between phenotype and genotype ranged from 64.7% to 84.3% depending on the GTT method. Only 46.9% of the R5 phenotypes were predicted as R5 by all GTT tools while R5X4 phenotypes were predicted as X4 by four methods, but not by Raymond's method. All six tested phenotypic R5 clones, as well as five of six of dual tropic clones, showed a dose response to maraviroc. CONCLUSION: There is a high discordance between GTT methods, which underestimates the presence of R5 and overestimates X4 strains compared to a phenotypic assay. Currently available GTT algorithms should be further improved for tropism prediction in HIV-1C. Maraviroc has an in vitro activity against most HIV-1C viruses and could be considered as an alternative regimen in individuals infected with CCR5-tropic HIV-1C viruses.

Unique Phenotypic Characteristics of Recently Transmitted HIV-1 Subtype C Envelope Glycoprotein gp120: Use of CXCR6 Coreceptor by Transmitted Founder Viruses.

Adequate information on the precise molecular and biological composition of the viral strains that establish HIV infection in the human host will provide effective means of immunization against HIV infection. In an attempt to identify the transmitted founder (TF) virus and differentiate the biological properties and infectious potential of the TF virus from those of the population of the early transmitted viruses, 250 patient-derived gp120 envelope glycoproteins were cloned in pMN-K7-Luc-IRESs-NefΔgp120 to obtain chimeric viruses. Samples were obtained from eight infants who had recently become infected with HIV through mother-to-child transmission (MTCT) and two adults who acquired infection through the heterosexual route and were in the chronic stage of infection. Among the 250 clones tested, 65 chimeric viruses were infectious, and all belonged to HIV-1 subtype C. The 65 clones were analyzed for molecular features of the envelope, per-infectious-particle infectivity, coreceptor tropism, drug sensitivity, and sensitivity to broadly neutralizing antibodies. Based on genotypic and phenotypic analysis of the viral clones, we identified 10 TF viruses from the eight infants. The TF viruses were characterized by shorter V1V2 regions, a reduced number of potential N-linked glycosylation sites, and a higher infectivity titer compared to the virus variants from the adults in the chronic stage of infection. CXCR6 coreceptor usage, in addition to that of the CCR5 coreceptor, which was used by all 65 chimeric viruses, was identified in 13 viruses. The sensitivity of the TF variants to maraviroc and a standard panel of neutralizing monoclonal antibodies (VRC01, PG09, PG16, and PGT121) was found to be much lower than that of the virus variants from the adults in the chronic stage of infection.IMPORTANCE Tremendous progress has been made during the last three and half decades of HIV research, but some significant gaps continue to exist. One of the frontier areas of HIV research which has not seen a breakthrough yet is vaccine research, which is because of the enormous genetic diversity of HIV-1 and the unique infectious fitness of the virus. Among the repertoire of viral variants, the virus that establishes successful infection (transmitted founder [TF] virus) has not been well characterized yet. An insight into the salient features of the TF virus would go a long way toward helping with the design of an effective vaccine against HIV. Here we studied the biological properties of recently transmitted viruses isolated from infants who acquired infection from the mother and have come up with unique characterizations for the TF virus that establishes infection in the human host.

Ex-vivo antiretroviral potency of newer integrase strand transfer inhibitors cabotegravir and bictegravir in HIV type 1 non-B subtypes.

OBJECTIVE: To determine the antiretroviral activity of the integrase strand transfer inhibitors (INSTIs), raltegravir (RAL), elvitegravir (EVG), dolutegravir (DTG), cabotegravir (CAB) and bictegravir (BIC), against different subtypes as well as primary and acquired drug resistance mutations (DRMs) in a patient-cohort infected with diverse subtypes. DESIGN: Biochemical and virological drug sensitivity analyses using patient-derived HIV type 1 (HIV-1) genes and cross-sectional/longitudinal clinical study. METHODS: Assays for 50% inhibition of 3'-end processing (IC50-3EP), strand transfer (IC50-ST) and drug sensitivity for five INSTIs were done using patient-derived integrase or gag-pol genes from subtypes A1, B, C, 01_AE and 02_AG. Integrase from INSTI-naive (n = 270) and experienced (n = 96) patients were sequenced. RESULTS: RAL had higher IC50-ST than the other INSTIs for all subtypes. EVG had higher IC50-ST for HIV 1 subtype C (P < 0.05) and 02_AG (P < 0.05) than HIV 1 subtype B (HIV-1B). DTG showed lower IC50-ST in HIV 1 subtype C than HIV-1B (P = 0.003). In CAB , the non-B subtypes showed lower IC50-ST (P < 0.05) than HIV-1B. In BIC, lower IC50-ST in 01_AE (P = 0.017) and 02_AG (P = 0.045) than HIV-1B. In drug sensitivity assay, inhibiting virus replication by 50% for DTG [median (IQR) 2.14 (1.3-2.56)], CAB [1.68 (1.34-2.55)] and BIC [1.07 (0.22-2.53)] were lower than RAL and EVG. One patient had a primary DRMs (0.3%, 1/270), but 17 (6.3%) had one major accessory DRM, of which 12 were E157Q. CONCLUSION: The equal or higher potency in non-B subtypes of DTG, CAB and BIC compared with RAL and EVG confirms their suitability for use in countries dominated by non-B subtypes. Any impact of the high prevalence of major accessory mutations, especially E157Q, requires long-term follow-up studies.

The PTAP sequence duplication in HIV-1 subtype C Gag p6 in drug-naive subjects of India and South Africa.

BACKGROUND: HIV-1 subtype C demonstrates several biological properties distinct from other viral subtypes. One such variation is the duplication of PTAP motif in p6 Gag. PTAP motif is a key player in viral budding. Here, we studied the prevalence of PTAP motif duplication in subtype C viral strains in a longitudinal study. METHODS: In a prospective follow-up study, 65 HIV-1 seropositive drug-naive subjects were monitored in two different clinical cohorts of India for 2 years with repeated sampling at 6-month intervals. The viral RNA was extracted from plasma, the gag segment was amplified and sequenced. From a subset of viral isolates the sequences of pol, env and LTR were sequenced. Using HIV-1 gag amino acid sequences available from public databases and additional sequences derived from the Indian and South-African cohorts, we examined the nature of PTAP motif duplication in subtype C. RESULTS: In 16% (8 of 50) of the primary viral strains of India, we identified a sequence duplication of the PTAP motif in Gag p6. The length of the sequence duplication varied from 6 to 14 amino acids in the viral isolates but remained fixed within a subject over a period of 24-36 month follow-up. In the duplicated motif, the core PTAP motif was invariable, but the flanking residues were highly variable. In an acute phase clinical cohort of South Africa, in a subset of 75 subjects, we found the presence of the PTAP duplication at a frequency of 29.3%. An analysis of the gag sequences from the extant databases showed that unlike other subtypes of HIV-1, subtype C has a natural propensity to generate the PTAP motif duplication at a significantly higher frequency and of greater length. Additionally, the global prevalence of PTAP duplication in subtype C appears to be increasing progressively over the past 30 years. CONCLUSION: We showed that in subtype C, the duplication of the PTAP motif in p6 Gag involves sequence stretches of greater length, and at a much higher frequency as compared to other HIV-1 subtypes. Given that subtype C naturally lacks the Alix binding motif, the acquisition of an additional PTAP motif may confer replication advantage on this HIV-1 subtype. Further investigation is warranted to examine the significance of PTAP motif duplication on the replicative fitness of HIV-1.

Increased replication capacity following evolution of PYxE insertion in Gag-p6 is associated with enhanced virulence in HIV-1 subtype C from East Africa.

BACKGROUND: A lower virulence of HIV-1 subtype C (HIV-1C) is suggested to be related to the global dominance of HIV-1C. In this observational study, combining in vivo (clinical monitoring) and in vitro (genotypic, biochemical, and phenotypic assays), we explored whether HIV-1C from East Africa (HIV-1CEA ) is more pathogenic due to the evolution of a PYxE-insertion (CPYxEi ) in the gag-p6 that also could affect the therapy response. METHODS: HIV-1B (n = 112) and HIV-1CEA (n = 128)-infected individuals residing in Sweden were analyzed with regard to Gag-p6 genotype and clinically monitored. Based on the Gag-p6 characteristics, three HIV-1CEA and one HIV-1 B patient-derived p2-INT-recombinant virus (gag-p2/NCp7/p1/p6/pol-PR/RT/IN) were constructed to analyze viral growth kinetics (VGKs) and drug sensitivity assays. Reverse transcriptase (RT) from the same samples was cloned into the heterodimer expression plasmid (pRT6H-PROT) to analyze catalytic efficiency of RT. RESULTS: A higher viral failure rate and lower pre-therapy CD4+ T-cell counts were observed in HIV-1CEA -infected patients compared to HIV-1B-infected patients. In Gag-p6, PTAP-duplication was more common in HIV-1C. HIV-1CEA -infected patients with signature CPYxEi, evidenced very low pre-therapy CD4+ T-cell counts and suboptimal gain in CD4+ T-cells following therapy, as compared to the non-CPYxEi -strains indicating higher virulence. VGKs showed a statistically significant higher replication capacity (RC) for the CPYxEi viruses than the other two non-CPYxEi strains. No statistically significant difference was observed in the catalytic efficiency among HIV-1C RTs. CONCLUSIONS: This is the first evidence of polymerase independent increased virulence and RC in HIV-1CEA following PYxE-insertion that is associated with suboptimal CD4+ T-cell gain following therapy initiation. J. Med. Virol. 89:106-111, 2017. © 2016 Wiley Periodicals, Inc.

Multiplexed next-generation sequencing and de novo assembly to obtain near full-length HIV-1 genome from plasma virus.

Analysing the HIV-1 near full-length genome (HIV-NFLG) facilitates new understanding into the diversity of virus population dynamics at individual or population level. In this study we developed a simple but high-throughput next generation sequencing (NGS) protocol for HIV-NFLG using clinical specimens and validated the method against an external quality control (EQC) panel. Clinical specimens (n=105) were obtained from three cohorts from two highly conserved HIV-1C epidemics (India and Ethiopia) and one diverse epidemic (Sweden). Additionally an EQC panel (n=10) was used to validate the protocol. HIV-NFLG was performed amplifying the HIV-genome (Gag-to-nef) in two fragments. NGS was performed using the Illumina HiSeq2500 after multiplexing 24 samples, followed by de novo assembly in Iterative Virus Assembler or VICUNA. Subtyping was carried out using several bioinformatics tools. Amplification of HIV-NFLG has 90% (95/105) success-rate in clinical specimens. NGS was successful in all clinical specimens (n=45) and EQA samples (n=10) attempted. The mean error for mutations for the EQC panel viruses were <1%. Subtyping identified two as A1C recombinant. Our results demonstrate the feasibility of a simple NGS-based HIV-NFLG that can potentially be used in the molecular surveillance for effective identification of subtypes and transmission clusters for operational public health intervention.