HIV-1 Integrase Gene Research Articles

Identification of integrase inhibitor-related drug resistance mutations in newly diagnosed ART-naïve HIV patients

BackgroundIn China, the recommended treatment regimens for HIV-infected individuals were tenofovir in combination with lamivudine or emtricitabine as NRTIs, efavirenz or rilpivirine as NNRTIs, lopinavir/ritonavir as protease inhibitors, and raltegravir or dolutegravir as INSTIs. The development of drug resistance increases the risk of viral rebound, opportunistic infections, and ultimately treatment failure such that the early detection of resistance is ideal. This study was developed to explore primary drug resistance characteristics and genotypic distributions in newly diagnosed antiretroviral therapy (ART)-naïve HIV-1 patients in Nanjing with the goal of establishing a basis for their individualized treatment in the clinic. MethodsSamples of serum were collected from newly diagnosed ART-naïve HIV patients from the Second Hospital of Nanjing between May 2021 and May 2022. The HIV-1 integrase (IN), protease (PR), and reverse transcriptase (RT) gene coding sequences were amplified from these samples, sequenced, and assessed for drug resistance-related mutations. ResultsMajor integrase resistance-related mutations were detected in 4/360 amplified samples, with 5 other patient samples exhibiting accessory resistance mutations. The overall prevalence of PR and RT inhibitor-related transmitted drug resistance mutations (TDRMs) in this patient population was 16.99% (61/359). The most common mutations were non-nucleoside reverse transcriptase inhibitor-related mutations (51/359; 14.21%), followed by those associated with nucleoside reverse transcriptase inhibitors (7/359; 1.95%) and protease inhibitors (7/359; 1.95%). Dual-resistant strains were also observed in a subset of patients. ConclusionsIn summary, this study is the first to have surveyed the prevalence of integrase inhibitor resistance-related mutations and other drug resistance-related mutations among newly diagnosed ART-naïve HIV-positive patients in Nanjing, China. These results highlight the need for further molecular surveillance-based monitoring of the HIV epidemic in Nanjing.

Affordable drug resistance genotyping of HIV-1 reverse transcriptase, protease and integrase genes, for resource limited settings

BackgroundAs use of dolutegravir (DTG) becomes more common in resource limited settings (RLS), the demand for integrase resistance testing is increasing. Affordable methods for genotyping all relevant HIV-1 pol genes (i.e., protease (PR), reverse transcriptase (RT) and integrase (IN)) are required to guide choice of future antiretroviral therapy (ART). We designed an in-house HIV-1 drug resistance (HIVDR) genotyping method that is affordable and suitable for use in RLS.MethodsWe obtained remnant plasma samples from CAPRISA 103 study and amplified HIV-1 PR, RT and IN genes, using an innovative PCR assay. We validated the assay using remnant plasma samples from an external quality assessment (EQA) programme. We genotyped samples by Sanger sequencing and assessed HIVDR mutations using the Stanford HIV drug resistance database. We compared drug resistance mutations with previous genotypes and calculated method cost-estimates.ResultsFrom 96 samples processed, we obtained sequence data for 78 (81%), of which 75 (96%) had a least one HIVDR mutation, with no major-IN mutations observed. Only one sample had an E157Q INSTI-accessory mutation. When compared to previous genotypes, 18/78 (23%) had at least one discordant mutation, but only 2/78 (3%) resulted in different phenotypic predictions that could affect choice of subsequent regimen. All CAPRISA 103 study sequences were HIV-1C as confirmed by phylogenetic analysis. Of the 7 EQA samples, 4 were HIV-1C, 2 were HIV-1D, and 1 was HIV-1A. Genotypic resistance data generated using the IDR method were 100% concordant with EQA panel results. Overall genotyping cost per sample was estimated at ~ US$43–$US49, with a processing time of ~ 2 working days.ConclusionsWe successfully designed an in-house HIVDR method that is suitable for genotyping HIV-1 PR, RT and IN genes, at an affordable cost and shorter turnaround time. This HIVDR genotyping method accommodates changes in ART regimens and will help to guide HIV-1 treatment decisions in RLS.

Primary resistance to integrase inhibitors in Shenzhen.

In recent years, integrase strand transfer inhibitor (INSTI)-containing regimens have been increasingly adopted in treatment for HIV/AIDS and promoted as non-occupational post-exposure prophylaxis in China. This study aims to describe the prevalence of resistance to integrase and drug resistance mutations (DRMs) among ART-naive patients in Shenzhen, China. Serum samples and demographic information were collected from newly reported ART-naive patients in Shenzhen in 2020. The study sequenced the coding sequence of the HIV-1 integrase gene and determined the DRMs.​. In this study, 1682 newly reported cases were included and 1071 of them were successfully sequenced finally. The prevalence of primary drug resistance was 1.77%, with 19 samples showing varying degrees of resistance to INSTIs. The study detected six major DRMs in 16 individuals and eight accessory DRMs in 24 individuals. The prevalence of transmitted drug resistance (TDR) mutations was 1.21%, with five transmitted mutations detected in 13 individuals. The prevalence of drug resistance to raltegravir and elvitegravir was statistically higher than to bictegravir, cabotegravir and dolutegravir. The prevalence of INSTI resistance in Shenzhen in 2020 was relatively high. ​Continued surveillance for resistance to INSTIs is recommended and treatment regimens should be adopted based on the pattern of resistance to INSTIs. ​Dolutegravir or bictegravir is first recommended when considering INSTIs as treatment regimens.

HIV-1 genetic diversity and transmitted drug resistance to integrase strand transfer inhibitors among recently diagnosed adults in Porto Alegre, South Brazil.

The HIV-1 genetic diversity and the presence of transmitted drug resistance mutations (TDRMs) against integrase strand transfer inhibitors (INSTIs) were assessed sequencing samples of antiretroviral (ARV)-naive HIV-1-infected individuals from South Brazil. Viral RNA from 42 ART-naive individuals was submitted to complete HIV-1 integrase gene amplification by RT-PCR and sequencing. Viral strains carrying TDRMs against INSTIs were not detected in the present study. However, the polymorphisms L74M and L74I were each observed in 4.8% of the individuals. These accessory mutations have been reported as putative causes of TDRMs in ART with raltegravir, but only when associated with additional major mutations. When submitted to HIV-1 subtyping, 50% were classified as subtype C, 21% as recombinant BC, 19% as subtype B, 4.8% as subtype F1 and 4.8% as recombinant CF1. All 42 ARV-naive individuals were apparently susceptible to INSTIs, included in the Brazilian therapeutic guideline since 2009. To the best of our knowledge, this is the first study to evaluate TDRMs against INSTIs in Brazil. The most prevalent HIV-1 subtypes were subtype C, followed by the recombinant BC and subtype B, which is in agreement with previous studies. However, the presence of subtype F1 and recombinant CF1 reported herein was not observed in previous studies.

Pre-Treatment Integrase Inhibitor Resistance and Natural Polymorphisms among HIV-1 Subtype C Infected Patients in Ethiopia.

Dolutegravir-based antiretroviral therapy (ART) has been scaled up in many developing countries, including Ethiopia. However, subtype-dependent polymorphic differences might influence the occurrence of HIV-drug-resistance mutations (HIVDRMs). We analyzed the prevalence of pre-treatment integrase strand transfer inhibitor (INSTI) HIVDRMs and naturally occurring polymorphisms (NOPs) of the integrase gene, using plasma samples collected as part of the national HIVDR survey in Ethiopia in 2017. We included a total of 460 HIV-1 integrase gene sequences from INSTI-naïve (n = 373 ART-naïve and n = 87 ART-experienced) patients. No dolutegravir-associated HIVDRMs were detected, regardless of previous exposure to ART. However, we found E92G in one ART-naïve patient specimen and accessory mutations in 20/460 (4.3%) of the specimens. Moreover, among the 288 integrase amino acid positions of the subtype C, 187/288 (64.9%) were conserved (<1.0% variability). Analysis of the genetic barrier showed that the Q148H/K/R dolutegravir resistance pathway was less selected in subtype C. Docking analysis of the dolutegravir showed that protease- and reverse-transcriptase-associated HIVDRMs did not affect the native structure of the HIV-1 integrase. Our results support the implementation of a wide scale-up of dolutegravir-based regimes. However, the detection of polymorphisms contributing to INSTI warrants the continuous surveillance of INSTI resistance.

The frequency of HIV-1 infection and surveillance drug-resistant mutations determination among Iranians with high-risk behaviors, during 2014 to 2020.

Background and Objectives:Human immunodeficiency virus (HIV) has various transmission routes. Instant antiretroviral therapy (ART) is the recommended treatment for HIV infection. Highly active antiretroviral therapy (HAART) significantly decreases the acquired immunodeficiency syndrome (AIDS) and AIDS-related co-morbidities. Notwithstanding the suitability of HAART, the antiretrovirals (ARVs) have adverse effects and antiretroviral drug resistance mutations are reported among those who receive ARVs. In this survey, the abundance of HIV-1 infection in Iranians with high-risk behaviors, and detection of the surveillance drug-resistant mutations (SDRMs) were evaluated.Materials and Methods:This cross-sectional study was conducted on 250 individuals with high-risk behaviors from September 2014 to February 2020. HIV-1 Ag/Ab in plasma samples was detected using enzyme immunoassay (EIA) kits. The conserved region of HIV-1 was detected in the plasma samples by real-time polymerase chain reaction (PCR) assay. Furthermore, in individuals with positive HIV-1 RNA, HIV-1 viral load testing was performed. After amplification and sequencing of the HIV-1 protease, reverse transcriptase, and integrase genes, surveillance drug resistance mutation (SDRM) and phylogenetic analysis were determined.Results:Out of the 250 participants with high-risk behaviors, six (2.4%) were infected with HIV-1. According to the phylogenetic analysis, the CRF35_AD (83.3% or 5/6) was the dominant subtype, followed by CRF01_AE (16.7% or 1/6). In this research, in none of the HIV-1 infected patients, SDRM for protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), and integrase inhibitors (INs) were observed. Nevertheless, in one of the patients, V179L mutation was detected which is a rare non-polymorphic mutation and is listed as a rilpivirine (RPV) -associated resistance mutation.Conclusion:The results of the current survey revealed that 2.4% of people with high-risk behaviors are infected with HIV and the level of drug resistance mutations (DRMs) in these people is very low.

Viral suppression is associated with HIV-antibody level and HIV-1 DNA detectability in early treated children at 2 years of age.

Early infant HIV diagnosis and antiretroviral therapy (ART) initiation are now implemented shortly after birth. Maintaining and monitoring ART adherence is difficult and requires frequent visits. We, therefore, investigated whether HIV antibodies and HIV-1 DNA levels are markers of cumulative viremia. We conducted a cross sectional investigation at 2 years of age of HIV antibodies and HIV-1 DNA levels in a well characterized cohort of 31 children who started ART shortly after birth. HIV antibodies were measured by a combination of the Abbott ARCHITECT HIV Ag/Ab Combo and Geenius HIV 1/2 supplemental assays; and total HIV-1 DNA quantified using a sensitive quantitative PCR (qPCR) assay targeting the HIV-1 integrase gene. Infant post-exposure prophylaxis consisted of zidovudine (AZT) and nevirapine (NPV) (or NVP only, in one child) within 1 day of birth, transitioning, after positive diagnosis, to three-drug ART, at a median [interquartile range (IQR)] of 7 (4-9.5) days. Twelve of 31 children had well suppressed HIV plasma viral loads (HIVVL) and the remainder periods of viremia (HIVVL > 100 copies/ml after 3 months of ART), classified as non-suppressed. At 24 months of age: 11 of 12 (92%) of well suppressed children had undetectable HIV-1 antibodies versus 3 of 19 (16%) non-suppressed children (P < 0.001) and 7 of 12 (58%) well suppressed children had undetectable HIV-1 DNA versus 3 of 19 (16%) non-suppressed children (P = 0.02). Considering low assay costs and the high proportion of well suppressed children with undetected antibody levels at 2 years, HIV antibody levels may be a valuable marker of cumulative adherence in children who start treatment shortly after birth and could prompt adherence and viral load investigation.

Evaluation of Diversity Levels of the Integrase Gene Sequences Coming from HIV-1 Virus, Supporting the Lack of Target Specificity of Ivermectin vs. the Integrase-Importin Complex in SARS-COV-2 Infection

Therapies with new drugs have been appearing in tests worldwide as potential inhibitors of sars-cov-2 virus replication. Recently, one of these drugs, Ivermectin, was reported as an inhibitor of the nuclear import of HIV-1 proteins in vitro, soon becoming the target of an international prospecting work (not yet published), with patients tested for COVID-19. However, understanding the evolutionary aspects of the biological components involved in the complex drug-nuclear import helps in understanding how these relationships exist in the deactivation of viral infections. Thus, 153 sequences of the HIV-1 integrase gene were analyzed for their genetic structure and molecular diversity and the presence of two distinct groups for the Gene and not only one was detected as well as different degrees of structuring for each of these groups. These results support the interpretation of the lack of conservation of the HIV-1 gene and that the number of existing polymorphisms, only for this structure of the complex, implies the non-efficiency of a drug at population levels. Thus, the molecular diversity found in HIV-1 can be extrapolated to other viruses, such as Including, SARS-CoV-2 and the functionality of the drug, interacting with the integrase-importin complex, can be further decreased.

Variability in HIV-1 Integrase Gene and 3'-Polypurine Tract Sequences in Cameroon Clinical Isolates, and Implications for Integrase Inhibitors Efficacy.

Integrase strand-transfer inhibitors (INSTIs) are now included in preferred first-line antiretroviral therapy (ART) for HIV-infected adults. Studies of Western clade-B HIV-1 show increased resistance to INSTIs following mutations in integrase and nef 3′polypurine tract (3′-PPT). With anticipated shifts in Africa (where 25.6-million HIV-infected people resides) to INSTIs-based ART, it is critical to monitor patients in African countries for resistance-associated mutations (RAMs) affecting INSTIs efficacy. We analyzed HIV-1 integrase and 3′-PPT sequences in 345 clinical samples from INSTIs-naïve HIV-infected Cameroonians for polymorphisms and RAMs that affect INSTIs. Phylogeny showed high genetic diversity, with the predominance of HIV-1 CRF02_AG. Major INSTIs RAMs T66A and N155K were found in two (0.6%) samples. Integrase polymorphic and accessory RAMs found included T97A, E157Q, A128T, M50I, S119R, L74M, L74I, S230N, and E138D (0.3′23.5% of samples). Ten (3.2%) samples had both I72V+L74M, L74M+T97A, or I72V+T97A mutations; thirty-one (9.8%) had 3′-PPT mutations. The low frequency of major INSTIs RAMs shows that INSTIs-based ART can be successfully used in Cameroon. Several samples had ≥1 INSTIs accessory RAMs known to reduce INSTIs efficacy; thus, INSTIs-based ART would require genetic surveillance. The 3′-PPT mutations could also affect INSTIs. For patients failing INSTIs-based ART with no INSTIs RAMs, monitoring 3′-PPT sequences could reveal treatment failure etiology.

Characterization of HIV-1 Integrase Gene and Resistance Associated Mutations Prior to Roll out of Integrase Inhibitors by Kenyan National HIV-Treatment Program in Kenya.

Antiretroviral therapy containing an integrase strand transfer inhibitor plus two Nucleoside Reverse Transcriptase inhibitors has now been recommended for treatment of HIV-1-infected patients. This thus determined possible pre-existing integrase resistance-associated mutations in the integrase gene prior to introduction of integrase inhibitors combination therapy in Kenya. Drug experienced HIV patients were enrolled at Kisii Teaching and Referral in Kenya. Blood specimens from (33) patients were collected for direct sequencing of HIV-1 polintegrase genes. Drug resistance mutations were interpreted according to the Stanford algorithm and phylogenetically analysed using insilico tools. From pooled 188 Kenyan HIV integrase sequences that were analysed for drug resistance, no major mutations conferring resistance to integrase inhibitors were detected. However, polymorphic accessory mutations associated with reduced susceptibility of integrase inhibitors were observed in low frequency; M50I (12.2%), T97A (3.7%), S153YG, E92G (1.6%), G140S/A/C (1.1%) and E157Q (0.5%). Phylogenetic analysis (330 sequences revealed that HIV-1 subtype A1 accounted for majority of the infections, 26 (78.8%), followed by D, 5 (15.2%) and C, 2 (6%). The integrase inhibitors will be effective in Kenya where HIV-1 subtype A1 is still the most predominant. However, occurring polymorphisms may warrant further investigation among drug experienced individuals on dolutegravir combination or integrase inhibitor treatment.

HIV Type 1 Integrase Natural Polymorphisms in Viral Variants Circulating in FSU Countries.

Natural variability of integrase (IN) across HIV-1 variants may influence the emergence of resistant viruses. The most apparent explanation of this fact is the IN polymorphism and the associated differences in codon usage, which in turn, influence the probability and the terms of DRMs acquisition. Possible mechanisms by which polymorphisms affect DRMs emergence remain disputed and should still be clarified because these substitutions may be associated with a reduced activity of some INSTIs and may impact on ART regimen choice depending of HIV-1 subtype. The aim of this work was to assess the prevalence of naturally occurring polymorphisms within the HIV-1 integrase gene, which might influence the susceptibility to INSTIs, among the patients from Russia and former USSR countries, according to HIV-1 subtypes. A study involved 506 HIV-1 IN sequences of INSTI-naive patients from Russia, Ukraine, Armenia, Kyrgyzstan, Kazakhstan, Uzbekistan, Belarus, and Georgia. Among them, 194 sequences were newly obtained in this study and 312 were downloaded from Los-Alamos database. The proviral DNA was sequenced using an in-house PCR protocol designed on the basis of a well-conserved integrase region in order to detect all HIV-1 variants. The phylogenetic analyses based on IN population sequencing found subtype A6 being the most prevalent (259) (51.2%) in the collection studied, followed by subtype G (36) (7.1%), AGrecombinants (148) (29.3%), subtype B (50) (9.9%), and CRF03_AB (5) (1.0%). The major INSTI resistance-associated mutations (DRMs) were found only in two A6 samples. The prevalence of minor/ accessory substitutions depended on HIV-1 variants, while the most notable findings were L74I in subtype A6 (93.1%) and E157Q in subtype B (44.0%). Most of minor DRMs and polymorphic substitutions were concentrated in the central catalytic domain of the IN molecule. Both the DDE triad and HHCC zinc binding motifs were fully conserved. The results of the study suggest a very low risk of initiating INSTI-based therapy in patients with pre-existing polymorphic mutations in Russia and FSU countries. The therapy response in dominating HIV-1 genetic variants might be further studied in the future for a better understanding of their effect on INSTI susceptibility. The INSTI TDR is absent for the moment, but the risk may increase with expanded use of INSTIs, indicating the need for ongoing surveillance.

Early infant diagnosis of HIV-1 infection in Luanda, Angola, using a new DNA PCR assay and dried blood spots.

BackgroundEarly diagnosis and treatment reduces HIV-1-related mortality, morbidity and size of viral reservoirs in infants infected perinatally. Commercial molecular tests enable the early diagnosis of infection in infants but the high cost and low sensitivity with dried blood spots (DBS) limit their use in sub-Saharan Africa.ObjectivesTo develop and validate a sensitive and cheap qualitative proviral DNA PCR-based assay for early infant diagnosis (EID) in HIV-1-exposed infants using DBS samples.Study designChelex-based method was used to extract DNA from DBS samples followed by a nested PCR assay using primers for the HIV-1 integrase gene. Limit of detection (LoD) was determined by Probit regression using limiting dilutions of newly produced recombinant plasmids with the integrase gene of all HIV-1 subtypes and ACH-2 cells. Clinical sensitivity and specificity were evaluated on 100 HIV-1 infected adults; 5 infected infants; 50 healthy volunteers; 139 HIV-1-exposed infants of the Angolan Pediatric HIV Cohort (APEHC) with serology at 18 months of life.ResultsAll subtypes and CRF02_AG were amplified with a LoD of 14 copies. HIV-1 infection in infants was detected at month 1 of life. Sensitivity rate in adults varied with viral load, while diagnostic specificity was 100%. The percentage of HIV-1 MTCT cases between January 2012 and October 2014 was 2.2%. The cost per test was 8-10 USD which is 2- to 4-fold lower in comparison to commercial assays.ConclusionsThe new PCR assay enables early and accurate EID. The simplicity and low-cost of the assay make it suitable for generalized implementation in Angola and other resource-constrained countries.

Development of a phenotypic susceptibility assay for HIV-1 integrase inhibitors

Phenotypic resistance analysis is an indispensable method for determination of HIV-1 resistance and cross-resistance to novel drug compounds. Since integrase inhibitors are essential components of recent antiretroviral combination therapies, phenotypic resistance data, in conjunction with the corresponding genotypes, are needed for improving rules-based and data-driven tools for resistance prediction, such as HIV-Grade and geno2pheno[integrase]. For generation of phenotypic resistance data to recent integrase inhibitors, a recombinant phenotypic integrase susceptibility assay was established. For validation purposes, the phenotypic resistance to raltegravir, elvitegravir and dolutegravir of nine subtype-B virus strains, isolated from integrase inhibitor-naïve and raltegravir-treated patients was determined. Genotypic resistance analysis identified four virus strains harbouring RAL resistance-associated mutations. Phenotypic resistance analysis was performed as follows. The HIV-1 integrase genes were cloned into a modified pNL4-3 vector and transfected into 293T cells for the generation of recombinant virus. The integrase-inhibitor susceptibility of the recombinant viruses was determined via an indicator cell line. While raltegravir resistance profiles presented a high cross-resistance to elvitegravir, dolutegravir maintained in-vitro activity in spite of the Y143R and N155H mutations, confirming the strong activity of dolutegravir against raltegravir-resistant viruses. Solely a Q148H+G140S variant presented reduced susceptibility to dolutegravir. In conclusion, our phenotypic susceptibility assay permits resistance analysis of the integrase gene of patient-derived viruses for integrase inhibitors by replication-competent recombinants. Thus, this assay can be used to analyze phenotypic drug resistance of integrase inhibitors in vitro. It provides the possibility to determine the impact of newly appearing mutational patterns to drug resistance of recent integrase inhibitors.

Effect of HIV-1 Subtype C integrase mutations implied using molecular modeling and docking data.

The degree of sequence variation in HIV-1 integrase genes among infected patients and their impact on clinical response to Anti retroviral therapy (ART) is of interest. Therefore, we collected plasma samples from 161 HIV-1 infected individuals for subsequent integrase gene amplification (1087 bp). Thus, 102 complete integrase gene sequences identified as HIV-1 subtype-C was assembled. This sequence data was further used for sequence analysis and multiple sequence alignment (MSA) to assess position specific frequency of mutations within pol gene among infected individuals. We also used biophysical geometric optimization technique based molecular modeling and docking (Schrodinger suite) methods to infer differential function caused by position specific sequence mutations towards improved inhibitor selection. We thus identified accessory mutations (usually reduce susceptibility) leading to the resistance of some known integrase inhibitors in 14% of sequences in this data set. The Stanford HIV-1 drug resistance database provided complementary information on integrase resistance mutations to deduce molecular basis for such observation. Modeling and docking analysis show reduced binding by mutants for known compounds. The predicted binding values further reduced for models with combination of mutations among subtype C clinical strains. Thus, the molecular basis implied for the consequence of mutations in different variants of integrase genes of HIV-1 subtype C clinical strains from South India is reported. This data finds utility in the design, modification and development of a representative yet an improved inhibitor for HIV-1 integrase.

Primary resistance to integrase strand-transfer inhibitors in Europe.

The objective of this study was to define the natural genotypic variation of the HIV-1 integrase gene across Europe for epidemiological surveillance of integrase strand-transfer inhibitor (InSTI) resistance. This was a multicentre, cross-sectional study within the European SPREAD HIV resistance surveillance programme. A representative set of 300 samples was selected from 1950 naive HIV-positive subjects newly diagnosed in 2006-07. The prevalence of InSTI resistance was evaluated using quality-controlled baseline population sequencing of integrase. Signature raltegravir, elvitegravir and dolutegravir resistance mutations were defined according to the IAS-USA 2014 list. In addition, all integrase substitutions relative to HXB2 were identified, including those with a Stanford HIVdb score ≥ 10 to at least one InSTI. To rule out circulation of minority InSTI-resistant HIV, 65 samples were selected for 454 integrase sequencing. For the population sequencing analysis, 278 samples were retrieved and successfully analysed. No signature resistance mutations to any of the InSTIs were detected. Eleven (4%) subjects had mutations at resistance-associated positions with an HIVdb score ≥ 10. Of the 56 samples successfully analysed with 454 sequencing, no InSTI signature mutations were detected, whereas integrase substitutions with an HIVdb score ≥ 10 were found in 8 (14.3%) individuals. No signature InSTI-resistant variants were circulating in Europe before the introduction of InSTIs. However, polymorphisms contributing to InSTI resistance were not rare. As InSTI use becomes more widespread, continuous surveillance of primary InSTI resistance is warranted. These data will be key to modelling the kinetics of InSTI resistance transmission in Europe in the coming years.

Persistent production of an integrase-deleted HIV-1 variant with no resistance mutation and wild-type proviral DNA in a treated patient.

An HIV-infected patient presenting an unexpected viral escape under combined antiretroviral treatment is described. The virus isolated from plasma contained a large deletion in the HIV-1 integrase gene but no known resistance mutation. Nested polymerase chain reactions (PCRs) with patient virus integrase-specific primers and probes were developed and used to detect the mutant from plasma, blood, rectal biopsies, and sperm. The variant progressively emerged during a period of therapy-induced virosuppression, and persisted at a low but detectable level for at least 5 years. Surprisingly, proviral DNA from lymphocytes, rectal cells, and sperm cells was, and remained, mainly wild type. Cellular HIV RNA with the deletion was detected only once from the rectum. The origin and mechanisms underlying this so far not described production at a detectable level are largely hypothetical. This observation raised concern about the ability of defective viruses to spread.

Stable HIV-1 integrase diversity during initial HIV-1 RNA Decay suggests complete blockade of plasma HIV-1 replication by effective raltegravir-containing salvage therapy

BackgroundThere is legitimate concern that minority drug-resistant mutants may be selected during the initial HIV-1 RNA decay phase following antiretroviral therapy initiation, thus undermining efficacy of treatment. The goal of this study was to characterize viral resistance emergence and address viral population evolution during the first phase of viral decay after treatment containing initiation.Findings454 sequencing was used to characterize viral genetic diversity and polymorphism composition of the HIV-1 integrase gene during the first two weeks following initiation of raltegravir-containing HAART in four ART-experienced subjects. No low-prevalence Raltegravir (RAL) drug resistance mutations (DRM) were found at baseline. All patients undergoing treatment received a fully active ART according to GSS values (GSS ≥ 3.5). No emergence of DRM after treatment initiation was detected. Longitudinal analysis showed no evidence of any other polymorphic mutation emergence or variation in viral diversity indexes.ConclusionsThis suggests that fully active salvage antiretroviral therapy including raltegravir achieves a complete blockade of HIV-1 replication in plasma. It is unlikely that raltegravir-resistant HIV-1 may be selected in plasma during the early HIV-1 RNA decay after treatment initiation if the administered therapy is active enough.

A Handheld Point-of-Care Genomic Diagnostic System

The rapid detection and identification of infectious disease pathogens is a critical need for healthcare in both developed and developing countries. As we gain more insight into the genomic basis of pathogen infectivity and drug resistance, point-of-care nucleic acid testing will likely become an important tool for global health. In this paper, we present an inexpensive, handheld, battery-powered instrument designed to enable pathogen genotyping in the developing world. Our Microfluidic Biomolecular Amplification Reader (µBAR) represents the convergence of molecular biology, microfluidics, optics, and electronics technology. The µBAR is capable of carrying out isothermal nucleic acid amplification assays with real-time fluorescence readout at a fraction of the cost of conventional benchtop thermocyclers. Additionally, the µBAR features cell phone data connectivity and GPS sample geotagging which can enable epidemiological surveying and remote healthcare delivery. The µBAR controls assay temperature through an integrated resistive heater and monitors real-time fluorescence signals from 60 individual reaction chambers using LEDs and phototransistors. Assays are carried out on PDMS disposable microfluidic cartridges which require no external power for sample loading. We characterize the fluorescence detection limits, heater uniformity, and battery life of the instrument. As a proof-of-principle, we demonstrate the detection of the HIV-1 integrase gene with the µBAR using the Loop-Mediated Isothermal Amplification (LAMP) assay. Although we focus on the detection of purified DNA here, LAMP has previously been demonstrated with a range of clinical samples, and our eventual goal is to develop a microfluidic device which includes on-chip sample preparation from raw samples. The µBAR is based entirely around open source hardware and software, and in the accompanying online supplement we present a full set of schematics, bill of materials, PCB layouts, CAD drawings, and source code for the µBAR instrument with the goal of spurring further innovation toward low-cost genetic diagnostics.

Resistance Mutations outside the Integrase Coding Region Have an Effect on Human Immunodeficiency Virus Replicative Fitness but Do Not Affect Its Susceptibility to Integrase Strand Transfer Inhibitors

Most studies describing phenotypic resistance to integrase strand transfer inhibitors have analyzed viruses carrying only patient-derived HIV-1 integrase genes (INT-recombinant viruses). However, to date, many of the patients on INSTI-based treatment regimes, such as raltegravir (RAL), elvitegravir (EVG), and dolutegravir (DTG) are infected with multidrug-resistant HIV-1 strains. Here we analyzed the effect of drug resistance mutations in Gag (p2/NCp7/p1/p6), protease (PR), reverse transcriptase (RT), and integrase (IN) coding regions on susceptibility to INSTIs and viral replicative fitness using a novel HIV-1 phenotyping assay. Initial characterization based on site-directed mutant INSTI-resistant viruses confirmed the effect of a series of INSTI mutations on reduced susceptibility to EVG and RAL and viral replicative fitness (0.6% to 99% relative to the HIV-1NL4-3 control). Two sets of recombinant viruses containing a 3,428-bp gag-p2/NCp7/p1/p6/pol-PR/RT/IN (p2-INT) or a 1,088 bp integrase (INT) patient-derived fragment were constructed from plasma samples obtained from 27 virologic failure patients participating in a 48-week dose-ranging study of elvitegravir, GS-US-183-0105. A strong correlation was observed when susceptibility to EVG and RAL was assayed using p2-INT- vs. INT-recombinant viruses (Pearson coefficient correlation 0.869 and 0.918, P<0.0001 for EVG and RAL, respectively), demonstrating that mutations in the protease and RT have limited effect on susceptibility to these INSTIs. On the other hand, the replicative fitness of viruses harboring drug resistance mutations in PR, RT, and IN was generally impaired compared to viruses carrying only INSTI-resistance mutations. Thus, in the absence of drug pressure, drug resistance mutations in the PR and RT contribute to decrease the replicative fitness of the virus already impaired by mutations in the integrase. The use of recombinant viruses containing most or all HIV-1 regions targeted by antiretroviral drugs might be essential to understand the collective effect of epistatic interactions in multidrug-resistant viruses.

Inhibition of HIV-1 Integrase gene expression by 10-23 DNAzyme

HIV Integrase (IN) is an enzyme that is responsible for the integration of the proviral genome into the human genome, and this integration step is the first step of the virus hijacking the human cell machinery for its propagation and replication. 10-23 DNAzyme has the potential to suppress gene expressions through sequence-specific mRNA cleavage. We have designed three novel DNAzymes, DIN54, DIN116, and DIN152, against HIV-1 Integrase gene using Mfold software and evaluated them for target site cleavage activity on the in vitro transcribed mRNA. All DNAzymes were tested for its inhibition of expression of HIV Integrase protein in the transiently transfected cell lines. DIN116 and DIN152 inhibited IN-EGFP expression by 80 percent and 70 percent respectively.