Defective proviruses significantly impact viral transcription and immune activation in men and women with HIV-1 subtype C in rural South Africa.

Introduction: The main obstacle to achieving an HIV-1 cure is the proviral reservoir. To promote equity in HIV cure strategies, it is crucial to study the viral reservoir of the predominant HIV-1 subtype C in both women and men. Therefore, we investigated the dynamics of the (intact) viral reservoir in relation to plasma viral load (VL), CD4 T cell count, and immune activation before and during 96 weeks of successful antiretroviral therapy (ART).

Does social need fulfillment moderate the association between socioeconomic status and health risk behaviours during pregnancy?

Socioeconomic differences in health risk behaviours during pregnancy may be influenced by social relations. In this study, we aimed to investigate if social need fulfillment moderates the association between socioeconomic status (SES) and health risk behaviours (smoking and/or alcohol consumption) during pregnancy. We used baseline data from the Lifelines Cohort Study merged with data from the Lifelines Reproductive Origin of Adult Health and Disease (ROAHD) cohort.

Dynamics of Low-Level Viremia and Immune Activation after Switching to a Darunavir-Based Regimen.

There is an ongoing debate regarding whether low-level viremia (LLV), in particular persistent LLV, during HIV treatment with optimal adherence originates from low-level viral replication, viral production, or both. We performed an observational study in 30 individuals with LLV who switched to a boosted darunavir (DRV)-based therapy. In-depth virological analyses were used to characterize the viral population and the (activity) of the viral reservoir.

Autopsy Study Defines Composition and Dynamics of the HIV-1 Reservoir after Allogeneic Hematopoietic Stem Cell Transplantation with CCR5Δ32/Δ32 Donor Cells.

Allo-HSCT with CCR5Δ32/Δ32 donor cells is the only curative HIV-1 intervention. We investigated the impact of allo-HSCT on the viral reservoir in PBMCs and post-mortem tissue in two patients. IciS-05 and IciS-11 both received a CCR5Δ32/Δ32 allo-HSCT.

A randomized study of intensified antiretroviral treatment monitoring versus standard-of-care for prevention of drug resistance and antiretroviral treatment switch.

Introduction: Standard-of-care antiretroviral treatment (ART) monitoring in low and middle-income countries consists of annual determination of HIV-RNA viral load with confirmatory viral load testing in case of viral rebound. We evaluated an intensified monitoring strategy of three-monthly viral load testing with additional drug exposure and drug resistance testing in case of viral rebound.

Methods: We performed an open-label randomized controlled trial (RCT) at a rural South African healthcare clinic, enrolling adults already receiving or newly initiating first-line ART.

Directing HIV-1 for degradation by non-target cells, using bi-specific single-chain llama antibodies.

While vaccination against HIV-1 has been so far unsuccessful, recently broadly neutralizing antibodies (bNAbs) against HIV-1 envelope glycoprotein were shown to induce long-term suppression in the absence of antiretroviral therapy in patients with antibody-sensitive viral reservoirs. The requirement of neutralizing antibodies indicates that the antibody mediated removal (clearance) of HIV-1 in itself is not efficient enough in these immune compromised patients. Here we present a novel, alternative approach that is independent of a functional immune system to clear HIV-1, by capturing the virus and redirecting it to non-target cells where it is internalized and degraded.

HIV-1 pretreatment drug resistance negatively impacts outcomes of first-line antiretroviral treatment.

Introduction: Pretreatment drug resistance (PDR) prevalence in sub-Saharan Africa is rising, but evidence of its impact on efavirenz (EFV)-based antiretroviral treatment (ART) is inconclusive. We determined the impact of PDR on outcomes of EFV-based ART in a subanalysis of a randomized clinical trial comparing different ART monitoring strategies implemented at a rural treatment facility in Limpopo, South Africa.

Methods: Participants initiating EFV-based first-line ART (2015-2017) were enrolled and received 96 weeks follow-up.

In-depth Characterization of Vaccine Breakthrough Infections With SARS-CoV-2 Among Health Care Workers in a Dutch Academic Medical Center.

Severe acute respiratory syndrome coronavirus 2 infection after coronavirus disease 2019 vaccination raises concerns about the emergence of vaccine escape variants. Here we characterize 14 breakthrough infections among 5860 fully vaccinated Dutch health care workers ≥14 days after the final dose of vaccination with either BNT162b2, mRNA-1273, or Ad26.COV2.

Immune activation correlates with and predicts CXCR4 co-receptor tropism switch in HIV-1 infection.

HIV-1 cell entry is mediated by binding to the CD4-receptor and chemokine co-receptors CCR5 (R5) or CXCR4 (X4). R5-tropic viruses are predominantly detected during early infection. A switch to X4-tropism often occurs during the course of infection.

Development of sensitive ddPCR assays to reliably quantify the proviral DNA reservoir in all common circulating HIV subtypes and recombinant forms.

Introduction: The latent reservoir is the main barrier on the road to HIV cure, and clinical approaches towards eradication are often evaluated by their effect on proviral DNA. To ensure inclusiveness and representativeness in HIV cure studies, proviral DNA quantification assays that are able to detect all common circulating HIV clades are urgently needed. Here, three HIV DNA assays targeting three different genomic regions were evaluated for their sensitivity and subtype-tolerance using digital PCR.

Rapid Rebound of a Preexisting CXCR4-tropic Human Immunodeficiency Virus Variant After Allogeneic Transplantation With CCR5 Δ32 Homozygous Stem Cells.

Allogeneic stem cell transplantation (alloSCT) of homozygous CCR5 Δ32 stem cells once resulted in the cure of human immunodeficiency virus (HIV) infection. We have recently reported a viral breakthrough in a similar setting. Here, we demonstrate that the rapid rebound after alloSCT was related to a highly replicative CXCR4-tropic HIV variant, which could already be detected before alloSCT.

A combinational CRISPR/Cas9 gene-editing approach can halt HIV replication and prevent viral escape.

HIV presents one of the highest evolutionary rates ever detected and combination antiretroviral therapy is needed to overcome the plasticity of the virus population and control viral replication. Conventional treatments lack the ability to clear the latent reservoir, which remains the major obstacle towards a cure. Novel strategies, such as CRISPR/Cas9 gRNA-based genome-editing, can permanently disrupt the HIV genome.

Short Communication: In Vitro Accumulation of Drug Resistance Mutations in Chimeric Infectious Clones Containing Subtype B or C Reverse Transcriptase and Selected with Tenofovir or Didanosine.

Highly active antiretroviral therapy (HAART) contributed to the improvement in the life expectancy of HIV-infected patients. However, the emergence of drug-resistant mutations (DRM) is a major viral factor impacting therapeutic failure. Differences in DRM can occur among HIV-1 subtypes.

Persistence of frequently transmitted drug-resistant HIV-1 variants can be explained by high viral replication capacity.

Background: In approximately 10% of newly diagnosed individuals in Europe, HIV-1 variants harboring transmitted drug resistance mutations (TDRM) are detected. For some TDRM it has been shown that they revert to wild type while other mutations persist in the absence of therapy. To understand the mechanisms explaining persistence we investigated the in vivo evolution of frequently transmitted HIV-1 variants and their impact on in vitro replicative capacity.

GS-8374, a prototype phosphonate-containing inhibitor of HIV-1 protease, effectively inhibits protease mutants with amino acid insertions.

Insertions in the protease (PR) region of human immunodeficiency virus (HIV) represent an interesting mechanism of antiviral resistance against HIV PR inhibitors (PIs). Here, we demonstrate the improved ability of a phosphonate-containing experimental HIV PI, GS-8374, relative to that of other PIs, to effectively inhibit patient-derived recombinant HIV strains bearing PR insertions and numerous other mutations. We correlate enzyme inhibition with the catalytic activities of corresponding recombinant PRs in vitro and provide a biochemical and structural analysis of the PR-inhibitor complex.

Formation of a quaternary complex of HIV-1 reverse transcriptase with a nucleotide-competing inhibitor and its ATP enhancer.

Nucleotide-competing reverse transcriptase inhibitors were shown to bind reversibly to the nucleotide-binding site of the reverse transcriptase (RT) enzyme of human immunodeficiency virus type 1 (HIV-1). Here, we show that the presence of ATP can enhance the inhibitory effects of the prototype compound INDOPY-1. We employed a combination of cell-free and cell-based assays to shed light on the underlying molecular mechanism.

Differential in vitro kinetics of drug resistance mutation acquisition in HIV-1 RT of subtypes B and C.

Background: HIV-1 subtype B is the most prevalent in developed countries and, consequently, it has been extensively studied. On the other hand, subtype C is the most prevalent worldwide and therefore is a reasonable target for future studies. Here we evaluate the acquisition of resistance and the viability of HIV-1 subtype B and C RT clones from different isolates that were subjected to in vitro selection pressure with zidovudine (ZDV) and lamivudine (3TC).

Modulation of HIV-1 Gag NC/p1 cleavage efficiency affects protease inhibitor resistance and viral replicative capacity.

Background: Mutations in the substrate of HIV-1 protease, especially changes in the NC/p1 cleavage site, can directly contribute to protease inhibitor (PI) resistance and also compensate for defects in viral replicative capacity (RC) due to a drug resistant protease. These NC/p1 changes are known to enhance processing of the Gag protein. To investigate the capacity of HIV-1 to modulate Gag cleavage and its consequences for PI resistance and RC, we performed a detailed enzymatic and virological analysis using a set of PI resistant NC/p1 variants (HXB2431V, HXB2436E+437T, HXB2437T and HXB2437V).

Telbivudine exerts no antiviral activity against HIV-1 in vitro and in humans.

Background: HIV-HBV-coinfected individuals who need to be treated only for their HBV infection have limited therapeutic options, since most approved anti-HBV agents have a risk of selecting for drug-resistant HIV mutants. In vivo data are inconclusive as to whether telbivudine (LdT) may exert antiviral effects against HIV. Thus, we investigated in further detail the antiviral activity and the biochemical properties of LdT against HIV-1.

Maraviroc is able to inhibit dual-R5 viruses in a dual/mixed HIV-1-infected patient.

Objectives: Maraviroc is the first licensed chemokine co-receptor 5 (CCR5) co-receptor antagonist in clinical practice. It is currently being used in patients harbouring exclusively CCR5-tropic virus. The objective of the study was to investigate the impact of maraviroc on viruses with different co-receptor preferences in a patient with a dual/mixed (D/M) infection.

Failure of treatment with first-line lopinavir boosted with ritonavir can be explained by novel resistance pathways with protease mutation 76V.

Background: Virological failure of first-line antiretroviral therapy based on lopinavir boosted with ritonavir (lopinavir/r) has rarely been associated with resistance in protease. We identified a new genotypic resistance pathway in 3 patients who experienced failure of first-line lopinavir/r treatment.

Methods: Viral protease and the C-term part of Gag were sequenced.

HIV-1 can persist in aged memory CD4+ T lymphocytes with minimal signs of evolution after 8.3 years of effective highly active antiretroviral therapy.

Background: Patients on long-term highly active antiretroviral therapy (HAART) were studied to determine persistence, drug resistance development, and evolution of HIV-1 proviral DNA.

Methods: Peripheral blood mononuclear cells were obtained by large volume blood drawn (500 mL) from 8 clinically successfully treated patients who had received uninterrupted HAART for up to 8.9 years.

Ninety-nine is not enough: molecular characterization of inhibitor-resistant human immunodeficiency virus type 1 protease mutants with insertions in the flap region.

While the selection of amino acid insertions in human immunodeficiency virus (HIV) reverse transcriptase (RT) is a known mechanism of resistance against RT inhibitors, very few reports on the selection of insertions in the protease (PR) coding region have been published. It is still unclear whether these insertions impact protease inhibitor (PI) resistance and/or viral replication capacity. We show that the prevalence of insertions, especially between amino acids 30 to 41 of HIV type 1 (HIV-1) PR, has increased in recent years.

A novel substrate-based HIV-1 protease inhibitor drug resistance mechanism.

Background: HIV protease inhibitor (PI) therapy results in the rapid selection of drug resistant viral variants harbouring one or two substitutions in the viral protease. To combat PI resistance development, two approaches have been developed. The first is to increase the level of PI in the plasma of the patient, and the second is to develop novel PI with high potency against the known PI-resistant HIV protease variants.

Persistence of HIV-1 variants with multiple protease inhibitor (PI)-resistance mutations in the absence of PI therapy can be explained by compensatory fixation.

Objective: To investigate the mechanism explaining the persistence of human immunodeficiency virus (HIV) type 1 variants with multiple protease inhibitor (PI)-resistance mutations in the absence of PI therapy.

Methods: Longitudinal genotypic analyses were performed on sequential samples obtained from 2 HIV-1-infected patients who had stopped PI therapy for 4 years. Replication capacity (RC) was determined using recombinant viruses.