HIV-1 Variants Research Articles

Genetic Diversity and Drug Resistance Mutations in HIV-1 pol Gene Sequences in the Philippines: A Retrospective Genomic Analysis

The Philippines has experienced a significant increase in HIV-1 infections in recent years, with a growing epidemic driven by the CRF01_AE strain. Understanding the genetic diversity of HIV-1 in the Philippines is crucial for the development of effective treatment strategies and the prevention of drug resistance. This study analyzed comprehensive data on common resistance mutation patterns from 2009 to 2017, revealing an increasing trend of mutations observed in NRTI and NNRTI resistance among the predominant CRF01_AE strains. The most common NRTI mutations observed were M184V, K65R, and S68G, whereas the most common NNRTI mutations were K103N, Y181C, and G190A. The study also found a high prevalence of M184V minority variants (0.5-20%) in treatment-naive patients, which could increase the risk of virological failure in 3TC-containing regimens. The findings of this study highlight the importance of comprehensive drug resistance surveillance and access to resistance testing to guide optimal first-line antiretroviral treatment selection and to manage the growing HIV-1 epidemic in the Philippines. The development of effective strategies to prevent and manage drug resistance is crucial to ensuring the long-term success of HIV treatment programs in the country.

The structural and mechanistic bases for the viral resistance to allosteric HIV-1 integrase inhibitor pirmitegravir.

Allosteric HIV-1 integrase (IN) inhibitors (ALLINIs) are investigational antiretroviral agents that potently impair virion maturation by inducing hyper-multimerization of IN and inhibiting its interaction with viral genomic RNA. The pyrrolopyridine-based ALLINI pirmitegravir (PIR) has recently advanced into phase 2a clinical trials. Previous cell culture-based viral breakthrough assays identified the HIV-1(Y99H/A128T IN) variant that confers substantial resistance to this inhibitor. Here, we have elucidated the unexpected mechanism of viral resistance to PIR. Although both Tyr99 and Ala128 are positioned within the inhibitor binding V-shaped cavity at the IN catalytic core domain (CCD) dimer interface, the Y99H/A128T IN mutations did not substantially affect the direct binding of PIR to the CCD dimer or functional oligomerization of full-length IN. Instead, the drug-resistant mutations introduced a steric hindrance at the inhibitor-mediated interface between CCD and C-terminal domain (CTD) and compromised CTD binding to the CCDY99H/A128T + PIR complex. Consequently, full-length INY99H/A128T was substantially less susceptible to the PIR-induced hyper-multimerization than the WT protein, and HIV-1(Y99H/A128T IN) conferred >150-fold resistance to the inhibitor compared with the WT virus. By rationally modifying PIR, we have developed its analog EKC110, which readily induced hyper-multimerization of INY99H/A128T in vitro and was ~14-fold more potent against HIV-1(Y99H/A128T IN) than the parent inhibitor. These findings suggest a path for developing improved PIR chemotypes with a higher barrier to resistance for their potential clinical use.IMPORTANCEAntiretroviral therapies save the lives of millions of people living with HIV (PLWH). However, the evolution of multi-drug-resistant viral phenotypes is a major clinical problem, and there are limited or no treatment options for heavily treatment-experienced PLWH. Allosteric HIV-1 integrase inhibitors (ALLINIs) are a novel class of antiretroviral compounds that work by a unique mechanism of binding to the non-catalytic site on the viral protein and inducing aberrant integrase multimerization. Accordingly, ALLINIs potently inhibit both wild-type HIV-1 and all drug-resistant viral phenotypes that have so far emerged against currently used therapies. Pirmitegravir, a highly potent and safe investigational ALLINI, is currently advancing through clinical trials. Here, we have elucidated the structural and mechanistic bases behind the emergence of HIV-1 integrase mutations in infected cells that confer resistance to pirmitegravir. In turn, our findings allowed us to rationally develop an improved ALLINI with substantially enhanced potency against the pirmitegravir-resistant virus.

Detection and characterization of HIV-1 group O and HIV-2 in the Central African Republic.

The Central African Republic (CAR) is characterized by widespread HIV epidemic with notable prevalence and genetic diversity. We herein analysed the genetic diversity of atypical non-M HIV-1 strains. In-house serotyping assays for variants of HIV-1 (M, N, O, P) and HIV-2 were used to test a biological collection of 6092 HIV-seropositive blood samples collected between 2003 and 2014 at the Institut Pasteur de Bangui. Samples indicative of recombinant M/O groups, HIV-2, or those that yield doubtful/negative results underwent further PCR tests and sequencing. We found six atypical HIV strains: specifically, three (0.05%) HIV-1 group O strains (subtype H) detected in samples from 2005, 2008 and 2009, alongside three (0.05%) HIV-2 strains (two group A and one group B) identified in samples from 2007 and 2009. HIV-1/O strains showed a genetic link to Cameroon and Gabon strains. This study highlights the dominance of HIV-1/M in the CAR's HIV epidemic over time and underscores the infrequent occurrence of HIV-1 group O and HIV-2 strains. These findings validate the efficacy of WHO-recommended HIV testing protocols and emphasize the need for adaptive surveillance and management strategies to confront the complexities introduced by the genetic diversity of HIV strains.

HIV-1 diversity in viral reservoirs obtained from circulating T-cell subsets during early ART and beyond.

Even during extended periods of effective immunological control, a substantial dynamic of the viral genome can be observed in different cellular compartments in HIV-1 positive individuals, indicating the persistence of active viral reservoirs. To obtain further insights, we studied changes in the proviral as well as in the viral HIV-1 envelope (Env) sequence along with transcriptional, translational and viral outgrowth activity as indicators for viral dynamics and genomic intactness. Our study identified distinct reservoir patterns that either represented highly sequence-diverse HIV-1 populations or only a single / few persisting virus variants. The single dominating variants were more often found in individuals starting ART during early infection phases, indicating that early treatment might limit reservoir diversification. At the same time, more sequence-diverse HIV reservoirs correlated with a poorer immune status, indicated by lower CD4 count, a higher number of regimen changes and more co-morbidities. Furthermore, we noted that in T-cell populations in the peripheral blood, replication-competent HIV-1 is predominantly present in Lymph node homing TN (naïve) and TCM (central memory) T cells. Provirus genomes archived in TTM (transitional memory) and TEM (effector memory) T cells more frequently tended to carry inactivating mutations and, population-wise, possess changes in the genetic diversity. These discriminating properties of the viral reservoir in T-cell subsets may have important implications for new early therapy strategies, underscoring the critical role of early therapy in preserving robust immune surveillance and constraining the viral reservoir.

Global and regional genetic diversity of HIV-1 in 2010–21: systematic review and analysis of prevalence

The extensive global genetic diversity of HIV-1 poses a major challenge to HIV vaccine development. We aimed to determine recent estimates of and changes in the global and regional distributions of HIV-1 genetic variants. We conducted a systematic literature review by searching PubMed, Embase, Global Health, and CINAHL for studies containing country-specific HIV-1 subtyping data, published between Jan 1, 2010and Sep 16, 2022. The proportions of HIV-1 subtypes, circulating recombinant forms (CRFs), and unique recombinant forms (URFs) in each country were weighted by UNAIDS estimates of the numbers of people living with HIV (PLHIV) in each country to obtain regional and global prevalence estimates of HIV-1 subtypes, CRFs, and URFs with 95% CIs for the time periods 2010-15and 2016-21. The protocol is registered with PROSPERO, CRD42017067164. We obtained 1044datasets, containing HIV-1 subtyping data from 653 013PLHIV from 122countries in 2010-2021. In 2016-2021, subtype Caccounted for 50·4% (95% CI 50·2-50·7; n=18 570 462of 36 823 798) of global HIV infections, subtype Afor 12·4% (12·2-12·6; n=4 571 250), subtype Bfor 11·3% (11·1-11·5; n=4 157 686), subtype Gfor 2·9% (2·9-3·0; n=1 083 568), subtype Dfor 2·6% (2·5-2·7; n=945 815), subtype Ffor 0·9% (0·8-0·9; n=316 724), CRFs for 15·1% (14·9-15·3; n=5 564 566), and URFs for 2·0% (1·9-2·1; n=733 374). Subtypes H, J, and K each accounted for 0·1% or less of infections. Compared with 2010-15, we observed significant (p<0·0001) increases in global proportions of subtype A (0·9%, 95% CI 0·7to 1·1) and subtype C (3·4%, 3·0to 3·7) and decreases in subtype D (-0·5%, -0·6to -0·4), subtype G (-0·8%, -1·0to -0·7), CRFs (-1·0%, -1·3to -0·8), and URFs (-1·8%, -1·9to -1·7), with no changes for subtypes Band F. The global proportion of infections attributed torecombinants decreased from 21·6% (95% CI 21·4 to 21·7; n=7 099 252of 32 622 808) in 2010-15to 19·3% (19·1to 19·5; n=7 094 694of 36 823 798) in 2016-21 (-2·3%, 95% CI -2·6to -2·0; p<0·0001). Regional distributions of HIV-1 variants were complex and evolving, with global trends in the prevalence of HIV-1 variants supported by trends across the regions. Global and regional HIV-1 genetic diversity are complex and continue to evolve. Continued and improved surveillance of HIV-1 variants remains vital for HIV vaccine development and implementation. None.

HIV Vaccine Development at a Crossroads: New B and T Cell Approaches.

Despite rigorous scientific efforts over the forty years since the onset of the global HIV pandemic, a safe and effective HIV-1 vaccine remains elusive. The challenges of HIV vaccine development have proven immense, in large part due to the tremendous sequence diversity of HIV and its ability to escape from antiviral adaptive immune responses. In recent years, several phase 3 efficacy trials have been conducted, testing a similar hypothesis, e.g., that non-neutralizing antibodies and classical cellular immune responses could prevent HIV-1 acquisition. These studies were not successful. As a result, the field has now pivoted to bold novel approaches, including sequential immunization strategies to drive the generation of broadly neutralizing antibodies and human CMV-vectored vaccines to elicit MHC-E-restricted CD8+ T cell responses. Many of these vaccine candidates are now in phase 1 trials, with early promising results.

Molecular genetic monitoring of HIV-1 variants circulating in St. Petersburg

The aim of the study: to assess the genetic diversity of HIV-1 variants circulating in St. Petersburg.Materials and methods. The study included 289 patients with virological ART failure in 2022 in the St. Petersburg AIDS Center. Fragments of the pol gene encoding integrase, reverse transcriptase and protease were analyzed by polymerase chain reaction and Sanger sequencing. Phylogenetic tree created by the Neighbor-joining method with 1000 repeats of nucleotide sequences, bootstrap values &gt;70. To assess the circulation of HIV genovariants in dynamics in St. Petersburg, sequences and clinical and laboratory parameters obtained from 544 patients since 2018. The total sample included 833 samples (289 were collected in 2022), compared with the results of a study from 1104 HIV-infected patients in 2006–2011.Results and discussion. Monovariants of HIV dominated in the examined patients (95.1%, 275 people), subtype A6 — 88.2% (255 people); subtype B — 5.9% (17 people); C — 0.3% (1 person); G — 0.7% (2 people), the proportion of recombinant forms — 4.9% (14 people). In the sample collection, the proportion of new HIV cases of non-A subtype was 13.3% in 2006–2011, and 11.1% in 2018–2022. A significant increase in the incidence of recombinant forms of HIV-1 was revealed from 1.6% to 3.5% (c2=6.111; p=0.014). In the group (2018–2022), the recombinant form of CRF63_02A6 was more common (15/29 people).Conclusion. Phylogenetic analyses makes it possible to determine HIV subtypes, but also to establish the potential geographical origin of the virus, to identify transmission clusters taking into account the socio-demographic indicators of HIV-infected patients. Molecular epidemiological monitoring can be used to develop and implement programs to counter the spread of HIV among the population. The dominant genetic variant of HIV circulating in St. Petersburg is sub-subtype A6, as it was 10 years ago. The proportion of new cases of infection with non-A subtype of HIV remains stable, with a downward trend. The increase in the frequency of detection of recombinant forms of HIV-1 is probably related to the migration processes of the population.

Variability of VPU protein in HIV-1 sub-subtype A6 in patients with different stages of HIV infection

The aim of the study: to compare the genetic diversity of the Vpu protein in HIV-1 in the people living with HIV (PLWH) with different stages of the disease.Materials and methods. An analysis was carried out of 259 clinical samples of whole blood from HIV-infected patients with no experience of taking antiretroviral therapy, who were observed at the Center for the Prevention and Control of AIDS and Infectious Diseases, Moscow, Russia. The analysis included the following stages: extraction of proviral DNA, amplification of the region of the virus genome containing the vpu gene, sequencing of amplification products, genotyping, comparison of conservation and amino acid substitutions in the Vpu protein sequences in PLWH with different stages of the disease.Results and discussion. In 255 out of 259 (98.4%) clinical samples, a sub-subtype A6 virus variant was identified. The consensus sequence of the Vpu sub-subtype A6 protein was obtained, which contained 81 amino acids. No significant differences in the conservation of Vpu protein sequences were found between HIV-1 variants obtained from patients with different stages of the disease. Amino acid substitution P3A was significantly more common in PLWH with the second stage of HIV infection.Conclusion. The results obtained highlight the issue of the influence of non-structural proteins of HIV-1 on the course of the disease and indicate directions for possible research in the future.

HIV-1 residual risk and pre-treatment drug resistance among blood donors: A sentinel surveillance from Gabon.

Surveillance of HIV-1 pre-treatment drug resistance (PDR) is essential for ensuring the success of first-line antiretroviral therapy (ART). Beside population-based surveys, sentinel surveillance of PDR and circulating HIV-1 clades in specific populations such as blood donors could efficiently inform decision-making on ART program. We therefore sought to ascertain HIV-1 residual infection, the threshold of PDR and viral diversity among recently-diagnosed blood donors in Gabon. A sentinel surveillance was conducted among 381 consenting blood donors at the National Blood Transfusion Center (NBTC) in Gabon from August 3,2020 to August, 31, 2021. In order to determine the residual risk of HIV transmission, viral load and HIV-1 Sanger-sequencing were performed at the Chantal BIYA International Reference Center (CIRCB)-Cameroon on HIV samples previously tested seronegative with ELISA in Gabon. Phylogeny was performed using MEGA X, PDR threshold>10% was considered high and data were analysed using p≤0.05 for statistical significance. Five HIV-negative blood donors had a detectable viral load indicating a high residual risk of HIV transmission. Among the samples successfully sequenced, four participants had major drug resistance mutations (DRMs), giving a threshold of PDR of 25% (4/16). By drug class, major DRMs targeting NNRTI (K103N, E138G), NRTIs (L210W) and PI/r (M46L). The most representative viral clades were CRF02_AG and subtype A1. The genetic diversity of HIV-1 had no significant effect on the residual risk in blood transfusion (CRF02_AG, P = 0.3 and Recombinants, P = 0.5). This sentinel surveillance indicates a high residual risk of HIV-1 transfusion in Gabon, thereby underscoring the need for optimal screening strategy for blood safety. Moreover, HIV-1 transmission goes with high-risk of PDR, suggesting suboptimal efficacy of ART. Nonetheless, the genetic diversity has limited (if any effect) on the residual risk of infection and PDR in blood donors.

Phylogenetic evidence of extensive spatial mixing of diverse HIV-1 group M lineages within Cameroon but not between its neighbours.

From the perspective of developing relevant interventions for treating HIV and controlling its spread, it is particularly important to comprehensively understand the underlying diversity of the virus, especially in countries where the virus has been present and evolving since the cross-species transmission event that triggered the global pandemic. Here, we generate and phylogenetically analyse sequences derived from the gag-protease (2010 bp; n = 115), partial integrase (345 bp; n = 36), and nef (719 bp; n = 321) genes of HIV-1 group M (HIV-1M) isolates sampled between 2000 and 2022 from two cosmopolitan cities and 40 remote villages of Cameroon. While 52.4% of all sequenced viruses belonged to circulating recombinant form (CRF) 02_AG (CRF02_AG), the remainder were highly diverse, collectively representing seven subtypes and sub-subtypes, eight CRFs, and 36 highly divergent lineages that fall outside the established HIV-1M classification. Additionally, in 77 samples for which at least two genes were typed, 31% of the studied viruses apparently had fragments from viruses belonging to different clades. Furthermore, we found that the distribution of HIV-1M populations is similar between different regions of Cameroon. In contrast, HIV-1M demographics in Cameroon differ significantly from those in its neighbouring countries in the Congo Basin (CB). In phylogenetic trees, viral sequences cluster according to the countries where they were sampled, suggesting that while there are minimal geographical or social barriers to viral dissemination throughout Cameroon, there is strongly impeded dispersal of HIV-1M lineages between Cameroon and other locations of the CB. This suggests that the apparent stability of highly diverse Cameroonian HIV-1M populations may be attributable to the extensive mixing of human populations within the country and the concomitant trans-national movements of major lineages with very similar degrees of fitness; coupled with the relatively infrequent inter-national transmission of these lineages from neighbouring countries in the CB.

Identification of Two HIV-1 CRF01_AE/B Recombinant Forms and a CRF01_AE/B/C Recombinant Form in Hebei Province, China.

In the Hebei province, Human Immunodeficiency Virus type one (HIV-1) recombinant strains of subtypes B, C, and CRF01_AE are emerging very rapidly and diversely. In order to confirm the characteristics of novel recombination forms, we aimed to analyze HIV-1 Near-full-length Genome sequences (NFLGs) obtained from three Men who have Sex with Men (MSM) in this study. Phylogenetic trees were constructed and breakpoints analysis was performed based on the NFLGs and each gene fragment to examine the gene recombination patterns of three new HIV-1 NFLGs. HIV-1 subtypes CRF01_AE and B were combined to generate the recombinant structures of the NFLGs 610 and 687. CRF01_AE, B, and C were combined to generate the recombinant structures of the NFLG 825. According to the NFLG phylogenetic tree, the NFLG 825 clustered with CRF65_cpx and the NFLGs 610 and 687 clustered with CRF68_01B. The recombination breakpoints analysis revealed that the recombination pattern of the NFLGs 610 and 687 was the insertion of subtype B fragment into the CRF01_AE backbone. Subregions I, II, and III were derived from CRF01_AE, subtype B, and CRF01_AE, respectively. The recombination pattern of the NFLG 825 contained ten fragments of subtypes CRF01_AE, C, and B. Finally, the above factors were formed using phylogenetic trees and breakpoints analysis, which were combined to get two CRF68_01B forms and one CRF65_cpx form. Our findings have suggested that it is crucial to keep an eye on the genetic diversity of HIV-1 in Hebei province.

Genetic variants of IL-10 promoter influence susceptibility to HIV-1 infection and disease progression in the Polish population: IL-10 polymorphisms and HIV-1

The risk of HIV-1 infection and the rate of disease progression vary considerably among individuals and the genetic makeup of the host may be one of the possible reasons for this. We aimed to determine association of functional single nucleotide polymorphism (SNPs), −1082A/G (rs1800896), −819C/T (rs1800871), and −592C/A (rs1800872) in IL-10 gene, with the susceptibility to HIV-1 infection and clinical parameters expressed as a baseline CD4+ T cell count, CD8+ T cell count, and viral load. Therapy naïve HIV-1 infected individuals and HIV-1 seronegative controls from Poland were recruited for this study. Genotyping results revealed significantly higher frequency of −1082G/G genotype (28.1 % vs 16.1 %; p = 0.0019, OR=0.49) and −1082G allele (47.6 % vs 38.8 %; p = 0.0028, OR = 0.70) as well as lower frequency of −592 and −819 heterozygosity (45.0 % vs 34.4 %; p = 0.0266, OR = 1.47) in controls compared to seropositive subjects. High producing haplotype GCC was associated with increased risk of HIV-1 infection (p = 0.0018, OR = 1.52). Individuals possessing −592 and −819 minor allele had significantly higher CD8+ T cell count compared to the wild type allele carriers (p = 0.0303). Moreover, presence of −1082G allele was related with lower viral load as well as CD4+ and CD8+ T cells counts among patients infected with R5 HIV-1 variant. Thus, IL-10 gene promoter variants may be a risk factor for HIV-1 transmission and may modulate disease progression in the Polish population.

Editorial: Characterization of HIV-1 variants: implications for HIV-1 prevention, treatment and cure

Editorial: Characterization of HIV-1 variants: implications for HIV-1 prevention, treatment and cure

Using viral diversity to identify HIV-1 variants under HLA-dependent selection in a systematic viral genome-wide screen.

The pathogenesis of HIV-1 infection is governed by a highly dynamic, time-dependent interaction between the host and the viral genome. In this study, we developed a novel systematic approach to assess the host-virus interaction, using average pairwise viral diversity as a proxy for time since infection, and applied this method to nearly whole viral genome sequences (n = 4,464), human leukocyte antigen (HLA) genotyping data (n = 1,044), and viral RNA load (VL) measurements during the untreated chronic phase (n = 829) of Swiss HIV Cohort Study participants. Our systematic genome-wide screen revealed for 98 HLA/viral-variant pairs a signature of immune-driven selection in the form of an HLA-dependent effect of infection time on the presence of HIV amino acid variants. Of these pairs, 12 were found to have an effect on VL. Furthermore, 28/58 pairs were validated by time-to-event analyses and 48/92 by computational HLA-epitope predictions. Our diversity-based approach allows a powerful and systematic investigation of the interaction between the virus and cellular immunity, revealing a notable subset of such interaction effects. From an evolutionary perspective, these observations underscore the complexity of HLA-mediated selection pressures on the virus that shape viral evolution and pathogenesis.

Identification of Two Novel HIV-1 Unique Recombinant Forms (CRF01_AE/CRF07_BC) and Genomic Characterization in Tongzhou District of Beijing, China.

Continuous recombination and variation during replication could lead to rapid evolution and genetic diversity of HIV-1. Some studies had identified that it was easy to develop new recombinant strains of HIV-1 among the populations of men who have sex with men (MSM). Surveillance of genetic variants of HIV-1 in key populations was crucial for comprehending the development of regional HIV-1 epidemics. The finding was reported the identification of two new unique recombinant forms (URF 20110561 and 21110743) from individuals infected with HIV-1 in Tongzhou, Beijing in 2020-2022. Sequences of near full-length genome (NFLG) were amplified, then identification of amplification products used phylogenetic analyses. The result showed that CRF01_AE was the main backbone of 20110561 and 21110743. In the gag region of the virus, 20110561 was inserted two fragments from CRF07_BC, while in the pol and tat regions of the virus, 21110743 was inserted four fragments from CRF07_BC. The CRF01_AE parental origin in the genomes of the two URFs was derived from the CRF01_AE Cluster 4. In the phylogenetic tree, the CRF07_BC parental origin of 20110561 clustered with 07BC_N and the CRF07_BC parental origin of 21110743 clustered with 07BC_O. In summary, the prevalence of novel second-generation URFs of HIV-1 was monitored in Tongzhou, Beijing. The emergence of the novel CRF01_AE/CRF07_BC recombination demonstrated that there was a great significance of continuous monitoring of new URFs in MSM populations to prevent and control the spreading of new HIV-1 URFs.

HIV-1 diversity and pre-treatment drug resistance in the era of integrase inhibitor among newly diagnosed ART-naïve adult patients in Luanda, Angola

The surveillance of drug resistance in the HIV-1 naïve population remains critical to optimizing the effectiveness of antiretroviral therapy (ART), mainly in the era of integrase strand transfer inhibitor (INSTI) regimens. Currently, there is no data regarding resistance to INSTI in Angola since Dolutegravir-DTG was included in the first-line ART regimen. Herein, we investigated the HIV-1 genetic diversity and pretreatment drug resistance (PDR) profile against nucleoside/tide reverse transcriptase inhibitors (NRTIs), non-nucleoside reverse transcriptase inhibitors (NNRTIs), protease inhibitors (PIs), and INSTIs, using a next-generation sequencing (NGS) approach with MinION, established to track and survey DRMs in Angola. This was a cross-sectional study comprising 48 newly HIV-diagnosed patients from Luanda, Angola, screened between March 2022 and May 2023. PR, RT, and IN fragments were sequenced for drug resistance and molecular transmission cluster analysis. A total of 45 out of the 48 plasma samples were successfully sequenced. Of these, 10/45 (22.2%) presented PDR to PIs/NRTIs/NNRTIs. Major mutations for NRTIs (2.2%), NNRTIs (20%), PIs (2.2%), and accessory mutations against INSTIs (13.3%) were detected. No major mutations against INSTIs were detected. M41L (2%) and I85V (2%) mutations were detected for NRTI and PI, respectively. K103N (7%), Y181C (7%), and K101E (7%) mutations were frequently observed in NNRTI. The L74M (9%) accessory mutation was frequently observed in the INSTI class. HIV-1 pure subtypes C (33%), F1 (17%), G (15%), A1 (10%), H (6%), and D (4%), CRF01_AG (4%) were observed, while about 10% were recombinant strains. About 31% of detected HIV-1C sequences were in clusters, suggesting small-scale local transmission chains. No major mutations against integrase inhibitors were detected, supporting the continued use of INSTI in the country. Further studies assessing the HIV-1 epidemiology in the era of INSTI-based ART regimens are needed in Angola.

HIV-DRIVES: HIV drug resistance identification, variant evaluation, and surveillance pipeline.

The global prevalence of resistance to antiviral drugs combined with antiretroviral therapy (cART) emphasizes the need for continuous monitoring to better understand the dynamics of drug-resistant mutations to guide treatment optimization and patient management as well as check the spread of resistant viral strains. We have recently integrated next-generation sequencing (NGS) into routine HIV drug resistance (HIVDR) monitoring, with key challenges in the bioinformatic analysis and interpretation of the complex data generated, while ensuring data security and privacy for patient information. To address these challenges, here we present HIV-DRIVES (HIV Drug Resistance Identification, Variant Evaluation, and Surveillance), an NGS-HIVDR bioinformatics pipeline that has been developed and validated using Illumina short reads, FASTA, and Sanger ab1.seq files.

Natural Variation in HIV-1 Entry Kinetics Map to Specific Residues and Reveal an Interdependence Between Attachment and Fusion.

The first step of HIV-1 infection is entry, where virus-cell membrane fusion is driven by the HIV-1 envelope glycoprotein through a series of conformational changes. Some of the most broadly active entry inhibitors work by binding conformations that exist only transiently during entry. The lifetimes of these states and the kinetics of entry are important elements of inhibitor activity for which little is known. We demonstrate a remarkable range of kinetics among 257 diverse HIV-1 isolates and find that this phenotype is highly flexible, with multiple single-residue determinants. Examination of the kinetics of two conformational landmarks shed light on novel kinetic features that offer new details about the role of co-receptor engagement and provide a framework to explain entry inhibitor synergy.

2′-β-Methylselenyl nucleos(t)ide analogs as reverse transcriptase inhibitors against diverse HIV mutants

Nucleoside reverse transcriptase inhibitors (NRTIs) have been extensively studied as drugs targeting HIV RT. However, the practice or use of approved NRTIs lacking the 3ʹ-hydroxy group often promotes frequent HIV mutations and generates drug-resistance. Here, we describe a novel NRTI with 2′-β-methylselenyl modification. We found that this modification inhibited the DNA elongation reaction by HIV-1 RT despite having a 3′-hydroxy group. Moreover, the conformation of this nucleoside analog is controlled at C3′-endo, a conformation that resists excision from the elongating DNA by HIV RT. Accordingly, the designed analogs exhibited activity against both wild-type HIV and multidrug-resistant HIV mutants.

Evaluating the antibody response elicited by diverse HIV envelope immunogens in the African green monkey (Vervet) model

African Green (Vervet) monkeys have been extensively studied to understand the pathogenesis of infectious diseases. Using vervet monkeys as pre-clinical models may be an attractive option for low-resourced areas as they are found abundantly and their maintenance is more cost-effective than bigger primates such as rhesus macaques. We assessed the feasibility of using vervet monkeys as animal models to examine the immunogenicity of HIV envelope trimer immunogens in pre-clinical testing. Three groups of vervet monkeys were subcutaneously immunized with either the BG505 SOSIP.664 trimer, a novel subtype C SOSIP.664 trimer, CAP255, or a combination of BG505, CAP255 and CAP256.SU SOSIP.664 trimers. All groups of vervet monkeys developed robust binding antibodies by the second immunization with the peak antibody response occurring after the third immunization. Similar to binding, antibody dependent cellular phagocytosis was also observed in all the monkeys. While all animals developed potent, heterologous Tier 1 neutralizing antibody responses, autologous neutralization was limited with only half of the animals in each group developing responses to their vaccine-matched pseudovirus. These data suggest that the vervet monkey model may yield distinct antibody responses compared to other models. Further study is required to further determine the utility of this model in HIV immunization studies.