HIV-1 Strains Research Articles

HOPE springs eternal: lack of HIV superinfection in HIV Organ Policy Equity Act kidney transplants.

Kidney transplantation from donors with HIV to recipients with HIV (HIV D+/R+) is an emerging practice that has shown substantial clinical benefit. Sustained HIV superinfection, whereby a transplant recipient acquires a new strain of HIV from their organ donor, is a theoretical risk, which might increase chances of viral failure. In this issue of the JCI, Travieso, Stadtler, and colleagues present phylogenetic analysis of HIV from kidney tissue, urine, plasma, and cells from 12 HIV D+/R+ kidney transplants out to five years of follow-up. Early after transplant, donor HIV was transiently detected in five of 12 recipients, primarily from donors with untreated HIV and high-level viremia, consistent with a viral inoculum. Long-term, donor HIV was not detected in any recipients, demonstrating no sustained HIV superinfection. These reassuring data support earlier findings from South Africa and the United States and further confirm the safety of HIV D+/R+ transplantation.

Quantum mechanical analysis of newly synthesized HIV-1 protease inhibitors: evaluation of wild-type and resistant strain binding interactions.

Inhibition of HIV-1 protease is a cornerstone of antiretroviral therapy. However, the notorious ability of HIV-1 to develop resistance to protease inhibitors (PIs), particularly darunavir (DRV), poses a major challenge. Using quantum chemistry and computer simulations, this study aims to investigate the interactions between two novel PIs, GRL-004 and GRL-063, as well as a wild-type (WT) HIV strain and a DRV-resistant mutant strain. To do this, we used molecular docking, molecular dynamics simulations, and quantum mechanical calculations to check how well GRL-004 and GRL-063 bound to both WT and DRV-resistant proteases. The results show that GRL-004 and GRL-063 bind very well to ASP29 in the WT strain. ASP29 is an important amino acid in the HIV protease dimer. Remarkably, amino acids such as ILE50 in the WT strains showed substantial binding energies to both drugs. Quantum energy calculations showed a slight reduction in the energy affinity of the interaction between the MUT strain and the ligand GRL-063, compared to the WT strain. GRL-004 showed similar interaction energy for both strains, suggesting that it has greater plasticity than GRL-063 despite its lower interaction affinity. Furthermore, GLY49B demonstrated strong binding energies regardless of mutations. Other relevant residues with strong binding energies include GLY49B, PHE82A, PRO81A, ASP29A, ASP25A and ALA28B. This study improves our understanding of receptor-ligand dynamics and the adaptability of new protease inhibitors (PIs), which has profound implications for the innovation of future antiretroviral drugs.

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.

Fragment Addition-Based Design of Heteroaromatic-Biphenyl-DAPYs as Potent and Orally Available Non-nucleoside Reverse Transcriptase Inhibitors Featuring Significantly Enhanced Safety.

Our previously disclosed biphenyl-DAPY 3 emerged as a potent inhibitor against WT HIV-1 and various mutant strains. Yet, its journey toward clinical application was thwarted by pronounced cytotoxicity and low selectivity (CC50 = 6 μM, SI = 3515). The safety improvement approach we employed in this work entailed the incorporation of diverse heteroaromatic substituents at the C5 position to exploit the tolerant regions of the NNRTIs' binding pocket through fragment addition-based drug design strategy, ultimately leading to the identification of a series of novel heteroaromatic-biphenyl-DAPYs. The exemplary compound 10d revealed a striking reduction in cytotoxicity (CC50 > 272.81 μM), nearly 45.5 times lower than 3, while showcasing 15-fold increase in selectivity (SI > 52632). This analog sustained exceptional anti-HIV-1 activity against both WT HIV-1 (EC50 = 5 nM) and various mutant strains. Compared to 3, a markedly slower rate of metabolism in human liver microsomes of 10d was observed. Its pharmacokinetic profile was equally captivating, featuring excellent oral bioavailability (F = 57.4%). Moreover, 10d exhibited a delicate sensitivity toward CYP, minimal inhibition of hERG, and no detectable acute toxicity in vivo. These enchanting findings illuminated the potential of 10d as a promising candidate for HIV-1 therapy.

Detection of antiretroviral drug-resistant mutations and HIV-1 subtypes in circulation among men who have sex with men, SEM females and female sex workers: results of Vietnam's HIV Sentinel Surveillance Plus (HSS+) system, 2018 - 2020.

HIV drug resistance (HIVDR) can reduce the effectiveness of antiretroviral (ARV) drugs in preventing morbidity and mortality, limit options for treatment, and prevention. Our study aimed to assess HIV-1 subtypes and HIVDR among key populations in HIV Sentinel Surveillance Plus Behavior (HSS+) in 2018 and 2020. One-stage venue-based cluster sampling was used to recruit participants at hotspots identified for Men who have sex with men (MSM) in 7 provinces and SEM females and female sex worker (FSW) in 13 provinces. Participants completed a standard questionnaire about risk and preventive behaviors, and ART history, and provided intravenous blood for HIV testing. HIVDR testing was conducted on HIV-positive samples with VL >1,000 copies/ml. A total of 185/435 (42.5%) HIV-positive samples had viral load ≥1,000 copies/ml, of which 130/136 from MSM and 26/49 from FSW, were successfully sequenced. Six HIV-1 subtypes were detected (CRF01_AE, A, CRF07/08_BC, B, C, CRF25_cpx), with CRF01_AE (82.7%, 129/156) the most common. Drug resistance mutations were detected in 16.7% of participants overall (26/156), in 15.4% (20/130) of MSM, and in 23.1% (6/26) of FSW. Mutations associated with resistance to NNRTI were the most frequently detected (73.1%, 19/26). The high level of resistance was presented in NNRTI and NRTI classes. There are 10 major resistance mutations detected with NRTI (M184VI-25.0%, K65KR-50.0%, Y115F-25%), NNRTI (K103N-21.1%, E138A-10.5%, V106M-5.3%, K101E-5.3%, G190A-5.3%) PI (L33F-40.0%, M46L-20.0%). Vietnam's HSS+ system identified an emerging strain of HIV-1 and mutations associated with resistance to multiple drug classes among MSM and FSW.

Design, Synthesis, and Biological Evaluation of Darunavir Analogs as HIV-1 Protease Inhibitors.

Darunavir, a frontline treatment for HIV infection, faces limitations due to emerging multidrug resistant (MDR) HIV strains, necessitating the development of analogs with improved activity. In this study, a combinatorial in silico approach was used to initially design a series of HIV-1 PI analogs with modifications at key sites, P1' and P2', to enhance interactions with HIV-1 PR. Fifteen analogs with promising binding scores were selected for synthesis and evaluated for the HIV-1 PR inhibition activity. The variation of P2' substitution was found to be effective, as seen in 5aa (1.54 nM), 5ad (0.71 nM), 5ac (0.31 nM), 5ae (0.28 nM), and 5af (1.12 nM), featuring halogen, aliphatic, and alkoxy functionalities on the phenyl sulfoxide motif exhibited superior inhibition against HIV-1 PR compared to DRV, with minimal cytotoxicity observed in Vero and 293T cell lines. Moreover, computational studies demonstrated the potential of selected analogs to inhibit various HIV-1 PR mutations, including I54M and I84V. Further structural dynamics and energetic analyses confirmed the stability and binding affinity of promising analogs, particularly 5ae, which showed strong interactions with key residues in HIV-1 PR. Overall, this study underscores the importance of flexible moieties and interaction enhancement at the S2' subsite of HIV-1 PR in developing effective DRV analogs to combat HIV and other global health issues.

HIV Modulates Osteoblast Differentiation via Upregulation of RANKL and Vitronectin.

Bone loss is a prevalent characteristic among people with HIV (PWH). We focused on mesenchymal stem cells (MSCs) and osteoblasts, examining their susceptibility to different HIV strains (R5- and X4-tropic) and the subsequent effects on bone tissue homeostasis. Our findings suggest that MSCs and osteoblasts are susceptible to R5- and X4-tropic HIV but do not support productive HIV replication. HIV exposure during the osteoblast differentiation process revealed that the virus could not alter mineral and organic matrix deposition. However, the reduction in runt-related transcription factor 2 (RUNX2) transcription, the increase in the transcription of nuclear receptor activator ligand kappa B (RANKL), and the augmentation of vitronectin deposition strongly suggested that X4- and R5-HIV could affect bone homeostasis. This study highlights the HIV ability to alter MSCs' differentiation into osteoblasts, critical for maintaining bone and adipose tissue homeostasis and function.

Combining molecular transmission network analysis and spatial epidemiology to reveal HIV-1 transmission pattern among the older people in Nanjing, China

BackgroundIn China, the problem of HIV infection among the older people has become increasingly prominent. This study aimed to analyze the pattern and influencing factors of HIV transmission based on a genomic and spatial epidemiological analysis among this population.MethodsA total of 432 older people who were aged ≥ 50 years, newly diagnosed with HIV-1 between January 2018 and December 2021 and without a history of ART were enrolled. HIV-1 pol gene sequence was obtained by viral RNA extraction and nested PCR. The molecular transmission network was constructed using HIV-TRACE and the spatial distribution analyses were performed in ArcGIS. The multivariate logistic regression analysis was performed to analyze the factors associated with clustering.ResultsA total of 382 sequences were successfully sequenced, of which CRF07_BC (52.3%), CRF01_AE (32.5%), and CRF08_BC (6.8%) were the main HIV-1 strains. A total of 176 sequences entered the molecular network, with a clustering rate of 46.1%. Impressively, the clustering rate among older people infected through commercial heterosexual contact was as high as 61.7% and three female sex workers (FSWs) were observed in the network. The individuals who were aged ≥ 60 years and transmitted the virus by commercial heterosexual contact had a higher clustering rate, while those who were retirees or engaged other occupations and with higher education degree were less likely to cluster. There was a positive spatial correlation of clustering rate (Global Moran I = 0.206, P < 0.001) at the town level and the highly aggregated regions were mainly distributed in rural area. We determined three large clusters which mainly spread in the intra-region of certain towns in rural areas. Notably, 54.5% of cases in large clusters were transmitted through commercial heterosexual contact.ConclusionsOur joint analysis of molecular and spatial epidemiology effectively revealed the spatial aggregation of HIV transmission and highlighted that towns of high aggregation were mainly located in rural area. Also, we found vital role of commercial heterosexual contact in HIV transmission among older people. Therefore, health resources should be directed towards highly aggregated rural areas and prevention strategy should take critical persons as entry points.

Computational identification and analysis of CNP0269688 as a natural product inhibitor disrupting the interaction between the HIV matrix domain and tRNA.

Our research is dedicated to combating HIV by targeting its Matrix (MA) domain, which is crucial for viral assembly and replication. This strategy specifically aims to interrupt early-stage infection and deter drug resistance by focusing on this essential domain. Due to the MA domain's conservation across different HIV strains, our approach promises broad-spectrum efficacy, which is particularly crucial in regions marked by significant genetic diversity and resistance issues. In our study, we introduce CNP0269688, a natural product that exhibits high affinity for the HIV-1 Matrix. Through detailed molecular dynamics simulations, we have assessed the compound's structural stability and interaction dynamics, particularly its potential to hinder Protein-tRNA interactions. This analysis lays the groundwork for future experimental investigations. Our efforts are steps toward enhancing HIV treatment, reducing viral transmission, and curbing drug resistance, with the ultimate aim of controlling and eradicating the pandemic, thereby contributing significantly to public health and scientific advancement.

MARVEL-minimising the emergence and dissemination of HIV-1 drug resistance in Portuguese-speaking African Countries (PALOP): low-cost portable NGS platform for HIV-1 surveillance in Africa

BackgroundHIV-1 infections remain a global public health concern. Scaled-up antiretroviral treatment (ART) is crucial for reducing morbidity and mortality related to HIV/AIDS. The emergence of drug-resistance mutations (DRMs) compromises viral suppression and contributes to the continued HIV-1 transmission. Several reports indicate a recent increase in acquired (ADR) and transmitted (TDR) drug resistance in Africa, probably linked to the lack of implementation of HIV drug resistance (HIVDR) testing and suboptimal treatment adherence. Herein, we will develop a low-cost protocol using third-generation sequencing (Oxford Nanopore Technology) for HIV-1 surveillance in Portuguese-speaking African Countries - PALOP [Angola (AO), Cape Verde (CV), Mozambique (MZ), and Sao Tome & Principe (STP)].MethodsThis is a multicentric cross-sectional study that includes around 600 adult patients newly diagnosed with HIV-1 in the PALOP. An epidemiological questionnaire previously validated by our research team will be used to collect sociodemographic and clinical data. Also, whole blood samples will be collected and the plasma samples will be subjected to drug resistance testing using an in-house low-cost NGS protocol. Data analysis will involve bioinformatics, biostatistics and machine learning techniques to generate accurate and up-to-date information about HIV-1 genetic diversity, ADR and TDR.DiscussionThe implementation of this low-cost NGS platform for HIV-1 surveillance in the PALOP will allow: (i) to increase DRM surveillance capacity in resource-limited settings; (ii) to understand the pattern and determinants of dissemination of resistant HIV-1 strains; and (iii) to promote the development of technical and scientific skills of African researchers for genomic surveillance of viral pathogens and bioinformatics analysis. These objectives will contribute to reinforcing the capacity to combat HIV infection in Africa by optimizing the selection of ART regimens, improving viral suppression, and reducing ADR or TDR prevalence in PALOPs, with relevant implications for public health.

Conformational flexibility of HIV-1 envelope glycoproteins modulates transmitted/founder sensitivity to broadly neutralizing antibodies

HIV-1 envelope glycoproteins (Envs) of most primary HIV-1 strains exist in closed conformation and infrequently sample open states, limiting access to internal epitopes. Thus, immunogen design aims to mimic the closed Env conformation as preferred target for eliciting broadly neutralizing antibodies (bnAbs). Here we identify incompletely closed Env conformations of 6 out of 13 transmitted/founder (T/F) strains that are sensitive to antibodies that recognize internal epitopes typically exposed on open Envs. A 3.6 Å cryo-electron microscopy structure of unliganded, incompletely closed T/F Envs (1059-SOSIP) reveals protomer motion that increased sampling of states with incompletely closed trimer apex. We reconstruct de novo the post-transmission evolutionary pathway of a second T/F. Evolved viruses exhibit increased Env resistance to cold, soluble CD4 and 19b, all of which correlate with closing of the adapted Env trimer. Lastly, we show that the ultra-broad N6 bnAb efficiently recognizes different Env conformations and exhibits improved antiviral breadth against VRC01-resistant Envs isolated during the first-in-humans antibody-mediated-prevention trial.

Enhancing Precision in HIV Treatment: Validation of a Robust Next-Generation Sequencing System for Drug Resistance Mutation Analysis.

Multidrug-resistant HIV strains challenge treatment efficacy and increase mortality rates. Next-generation sequencing (NGS) technology swiftly detects variants, facilitating personalized antiretroviral therapy. This study aimed to validate the Vela Diagnostics NGS platform for HIV drug resistance mutation analysis, rigorously assessed with clinical samples and CAP proficiency testing controls previously analyzed by Sanger sequencing. The experimental approach involved the following: RNA extraction from clinical specimens, reverse transcription polymerase chain reaction (RT-PCR) utilizing the Sentosa SX 101 platform, library preparation with the Sentosa SQ HIV Genotyping Assay, template preparation, sequencing using the Sentosa SQ301 instrument, and subsequent data analysis employing the Sentosa SQ Suite and SQ Reporter software. Drug resistance profiles were interpreted using the Stanford HIV Drug Resistance Database (HIVdb) with the HXB2 reference sequence. The Vela NGS system successfully identified a comprehensive array of drug resistance mutations across the tested samples: 28 nucleoside reverse transcriptase inhibitors (NRTI), 25 non-nucleoside reverse transcriptase inhibitors (NNRTI), 25 protease inhibitors (PI), and 10 integrase gene-specific variants. Dilution experiments further validated the system's sensitivity, detecting drug resistance mutations even at viral loads lower than the recommended threshold (1000 copies/mL) set by Vela Diagnostics. This study underscores the validation and clinical applicability of the Vela NGS system, and its implementation may offer clinicians enhanced precision in therapeutic decision-making for individuals living with HIV.

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.

Sequence Notes: Near Full-Length Genome Analysis of the First-Reported HIV-1 Circulating Recombinant Form (CRF)_10CD in Uganda.

HIV-1 is characterized by remarkable genetic diversity resulting from its high replication rate, error-prone reverse transcriptase enzyme and recombination events. In Uganda, HIV-1 subtype diversity is mostly dominated by subtypes A, D, and A1/D Unique Recombinant Forms (URFs). In this study, deep sequences of HIV from patients with known antiretroviral therapy (ART) status were analyzed to determine the subtypes and to identify drug-resistance mutations circulating in the study population. Of the 187 participant samples processed for next-generation sequencing (NGS), 137 (73%) were successfully classified. The majority of HIV-1 strains were classified as subtype A (75, 55%), D (43, 31%), with other subtypes including C (3, 2%), A1/D (9, 7%) and CRF10_CD (1, <1%). Recombinant analysis of nine complete A1/D HIV genomes identified novel recombination patterns described herein. Furthermore, we report for the first time in Uganda, an HIV-1 CRF10_CD strain from a fisherfolk in a Lake Victoria Island fishing community.

Structure-based discovery of novel piperidine-biphenyl-DAPY derivatives as non-nucleoside reverse transcriptase inhibitors featuring improved potency, safety, and selectivity: From piperazine-biphenyl-DAPYs to piperidine-biphenyl-DAPYs

Starting from our previously reported nonnucleoside reverse transcriptase inhibitor (NNRTI, 3), continuous efforts were made to enhance its potency and safety through a structure-based drug design strategy. This led to the discovery of a series of novel piperidine-biphenyl-diarylpyrimidines (DAPYs). Compound 10p, the most active compound in this series, exhibited an EC50 value of 6 nM against wide-type HIV-1 strain, which was approximately 560-fold more potent than the initial compound 3 (EC50 = 3.36 μM). Furthermore, significant improvements were observed in cytotoxicity and selectivity (CC50 > 202.17 μM, SI > 33144) compared to compound 3 (CC50 = 14.84 μM, SI = 4). Additionally, compound 10p demonstrated increased inhibitory activity against clinically mutant virus strains (EC50 = 7–63 nM). Further toxicity evaluation revealed that compound 10p exhibited minimal CYP enzyme and hERG inhibition. Importantly, single-dose acute toxicity testing did not result in any fatalities or noticeable pathological damage in mice. Therefore, compound 10p can be regarded as a lead candidate for guiding further development of biphenyl-diarylpyrimidine NNRTIs with favorable druggability for HIV therapy.

Alpaca-derived nanobody targeting the hydrophobic pocket of the HIV-1 gp41 NHR broadly neutralizes HIV-1 by blocking six-helix bundle formation

The highly conserved hydrophobic pocket region of HIV-1 gp41 NHR triple-stranded coiled coil is crucial for the binding of CHR to NHR to form a six-helix bundle (6-HB). This pocket is only exposed instantaneously during fusion, making it an ideal target for antibody drug design. However, IgG molecule is too big to enter the pocket during the fusion process. Therefore, to overcome the steric hindrance and kinetic obstacles caused by the formation of gp41 pre-hairpin fusion intermediate, we obtained nanobodies (Nbs) targeting NHR by immunizing alpaca with an NHR-trimer mimic. Specifically, we identified a Nb, Nb-172, that exhibited potent and broadly neutralizing activity against HIV-1 pseudoviruses, HIV-1 primary isolates, and T20-resistant HIV-1 strains. In addition, the combinatorial use of mD1.22 and Nb-172 exhibited synergism in inhibiting HIV-1 infection inactivating cell-free virions. Nb-172 can competitively bind to the hydrophobic pocket of gp41 NHR to inhibit 6-HB formation. These findings suggest that Nb-172 merits further investigation as a potential therapeutic for HIV-1 infection.

Human Immunodeficiency Viral Reverse Transcriptases: Analyses of the Active Sites of the Polymerase Domain and Drug-Resistant Mutants of the Reverse Transcriptases

It is well-known that human immunodeficiency viruses (HIVs) cause the chronic, potentially life-threatening condition known as human Acquired Immuno-Deficiency Syndrome (AIDS). As the lifecycle of HIVs heavily depends on the crucial enzyme, the reverse transcriptase (RT), it has been used as a potential therapeutic target to treat and control the spread of AIDS. The active site amino acids of the polymerase domain of the RTs and their anti-HIV drug-binding sites are analyzed. The catalytic region of HIV RTs and the E. coli DNA polymerase I showed very similar active site amino acids, suggesting that HIV RTs would have possibly evolved from the bacterial DNA polymerase. The catalytic proton abstractor is identified as a K and the nucleotide selection amino acid as an N. However, the regular template-binding pair –YG- is slightly modified to a –YXG- in HIV RTs. Three completely conserved Ds in HIV RTs are involved in binding to the catalytic Mg2+. The sensitive and resistant strains of HIV-1 for the HIV antiretroviral drug, azidothymidine (AZT), a nucleoside analogue of thymidine, show only a few non-isofunctional amino acid replacements and are located mainly in the palm and thumb subdomains of the RT polymerase, whereas the rest of the polymerase catalytic core and metal-binding sites are completely conserved in AZT-sensitive and -resistant HIV-1 strains. In the drug-resistant mutants of non-nucleoside RT inhibitors of HIV-2, the crucial mutations are located mainly near the -MDD- motif of the catalytic metal-binding region. Even though a large number of amino acid replacements are seen between the RTs of HIV-1 and HIV-2, the polymerase active sites are completely conserved in both. The HIV-1 and HIV-2 catalytic and metal-binding sites are completely conserved in simian immunodeficiency virus (SIV) as well. The absence of DEDD-superfamily of proofreading exonuclease domain in the HIV RTs, might cause the virus to evolve rapidly in patients. A possible mechanism of action for the HIV RTs is also proposed.

NKp30 and NKG2D contribute to natural killer recognition of HIV-infected cells.

Natural killer (NK) cells respond rapidly in early HIV-1 infection. HIV-1 prevention and control strategies harnessing NK cells could be enabled by mechanistic understanding of how NK cells recognize HIV-infected T cells. Here, we profiled the phenotype of human primary NK cells responsive to autologous HIV-1-infected CD4 + T cells in vitro. We characterized the patterns of NK cell ligand expression on CD4 + T cells at baseline and after infection with a panel of transmitted/founder HIV-1 strains to identify key receptor-ligand pairings. CRISPR editing of CD4 + T cells to knockout the NKp30 ligand B7-H6, or the NKG2D ligands MICB or ULBP2 reduced NK cell responses to HIV-infected cells in some donors. In contrast, overexpression of NKp30 or NKG2D in NK cells enhanced their targeting of HIV-infected cells. Collectively, we identified receptor-ligand pairs including NKp30:B7-H6 and NKG2D:MICB/ULBP2 that contribute to NK cell recognition of HIV-infected cells.

RPLP1 restricts HIV-1 transcription by disrupting C/EBPβ binding to the LTR

Long-term non-progressors (LTNPs) of HIV-1 infection may provide important insights into mechanisms involved in viral control and pathogenesis. Here, our results suggest that the ribosomal protein lateral stalk subunit P1 (RPLP1) is expressed at higher levels in LTNPs compared to regular progressors (RPs). Functionally, RPLP1 inhibits transcription of clade B HIV-1 strains by occupying the C/EBPβ binding sites in the viral long terminal repeat (LTR). This interaction requires the α-helixes 2 and 4 domains of RPLP1 and is evaded by HIV-1 group M subtype C and group N, O and P strains that do not require C/EBPβ for transcription. We further demonstrate that HIV-1-induced translocation of RPLP1 from the cytoplasm to the nucleus is essential for antiviral activity. Finally, knock-down of RPLP1 promotes reactivation of latent HIV-1 proviruses. Thus, RPLP1 may play a role in the maintenance of HIV-1 latency and resistance to RPLP1 restriction may contribute to the effective spread of clade C HIV-1 strains.

Broad synergistic antiviral efficacy between a novel elite controller-derived dipeptide and antiretrovirals against drug-resistant HIV-1.

The naturally occurring dipeptide Tryptophylglycine (WG) is enhanced in human immunodeficiency virus (HIV-1) infected Elite Controllers (EC). We have shown that this dipeptide has an anti-HIV-1 effect and evaluated now its synergistic antiretroviral activity, in combination with current antiretrovirals against multi-drug resistant HIV-1 isolates. Drug selectivity assay with WG-am and ARVs agains HIV-1 resistant isolates were carried out. Subsequently, two methods, Chou-Talalay's Combination Index (CI) and ZIP synergy score (SS), were used to quantify the synergism. WG-am had a moderate/strong synergism with the four tested antiretrovirals: raltegravir, tenofovir, efavirenz, darunavir. WG-am:TDF had strong synergism at ED50, ED75, ED90 (CI: <0.2) in isolates resistant to protease inhibitors or integrase strand inhibitors (INSTI), and a slightly less synergism in isolates resistant to non-nucleoside or nucleotide reverse transcriptase inhibitors. WG-am combined with each of the four drugs inhibited all drug-resistant isolates with over 95% reduction at maximum concentration tested. The highest selectivity indexes (CC50/ED50) were in INSTI-resistant isolates. Our data suggest that WG, identified as occurring and enhanced in Elite Controllers has a potential to become a future treatment option in patients with HIV-1 strains resistant to any of the four major categories of anti-HIV-1 compounds.