Publications by authors named "Alberto Guardo"

Most of the studies using the colorectal tissue explants challenge model have been conducted after one single dose and before reaching a steady state. We consider that longer exposure as in 28-day postexposure prophylaxis (PEP) course and in an setting, such as after a sexual risk exposure to HIV could give us valuable information about these drugs. In a substudy we assessed pharmacokinetics, changes on immune system and rectal mucosal susceptibility to HIV-1 infection after taking maraviroc (MVC), raltegravir (RAL), and ritonavir-boosted lopinavir (LPV/r) PEP-based regimens in 30 men who have sex with men.

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The CD3 subunits of the T-cell antigen receptor (TCR) play a central role in regulation of surface TCR expression levels. Humans who lack CD3γ (γ) show reduced surface TCR expression levels and abolished phorbol ester (PMA)-induced TCR down-regulation. The response to PMA is mediated by a double leucine motif in the intracellular (IC) domain of CD3γ.

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Therapeutic vaccinations aim to re-educate human immunodeficiency virus (HIV)-1-specific immune responses to achieve durable control of HIV-1 replication in virally suppressed infected individuals after antiretroviral therapy (ART) is interrupted. In a double blinded, placebo-controlled phase IIa multicenter study, we investigated the safety and immunogenicity of intranodal administration of the HIVACAT T cell Immunogen (HTI)-TriMix vaccine. It consists of naked mRNA based on cytotoxic T lymphocyte (CTL) targets of subdominant and conserved HIV-1 regions (HTI), in combination with mRNAs encoding constitutively active TLR4, the ligand for CD40 and CD70 as adjuvants (TriMix).

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There are few studies comparing the safety and immunogenicity of the same HIV immunogen in healthy volunteers and HIV-infected individuals. We analyzed demographics, adverse events (AEs), and immunogenicity against vaccinia virus in preventive (RISVAC02, = 24 low-risk HIV-negative volunteers) and therapeutic (RISVAC03, = 20 successfully treated chronically HIV-1-infected individuals) vaccine phase-I clinical trials that were performed with the same design and the same immunogen (modified vaccinia virus Ankara-B: MVA-B). Total AEs were significantly higher in HIV-infected patients (mean AEs/patient 6.

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Background: Atripla dose reduction decreases subclinical toxicity and maintains viral suppression in HIV+ individuals but the virological efficacy and immunological safety of this strategy needs to be further confirmed.

Methods: Virologically suppressed HIV-infected adults on Atripla once-daily were randomized 1 : 1 to reduce therapy to 3 days a week (3W, n = 30) or to maintain it unchanged (once-daily, n = 31). HIV-1 reservoir (total and integrated HIV-1 DNA in CD4 cells) and immunological cell activation (CD38 and HLA-DR), senescence (CD57 and CD28), apoptosis (annexinV) as well as T-naive, effector memory (TEM) (CCR7, CD45RA) and stem cell memory (TSCM) (CD954 and CD27) populations were measured at baseline, 24 and 48 weeks.

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Objective: The efficacy of therapeutic vaccines against HIV-1 infection has been modest. New inerts to redirect responses to vulnerable sites are urgently needed to improve these results.

Design: We performed the first-in-human clinical trial with naked mRNA (iHIVARNA) combining a dendritic cell activation strategy (TriMix:CD40L+CD70+caTLR4 RNA) with a novel HIV immunogen sequences (HTI immunogen).

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Background: Antiretroviral drugs contained in single tablet Atripla have pharmacokinetic properties that could allow for longer than once-daily dosing. We hypothesized that simplifying Atripla once daily to 3-day per week would be feasible, able to maintain viral suppression and less toxic.

Methods: Virologically suppressed (≥2 years) HIV+ adults on Atripla once daily, CD4 greater than 350 cells/μl at inclusion, and no prior documented virological failure or evidence of resistance mutations to efavirenz, tenofovir, or emtricitabine were randomized to maintain their once-daily (OD) regimen or to reduce it to 3 days (Mondays, Wednesdays, and Fridays) a week (3W) (A-TRI-WEEK pilot trial).

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Background: We have previously shown that an HIV vaccine regimen including three doses of HIV-modified vaccinia virus Ankara vector expressing HIV-1 antigens from clade B (MVA-B) was safe and elicited moderate and durable (1 year) T-cell and antibody responses in 75% and 95% of HIV-negative volunteers (n = 24), respectively (RISVAC02 study). Here, we describe the long-term durability of vaccine-induced responses and the safety and immunogenicity of an additional MVA-B boost.

Methods: 13 volunteers from the RISVAC02 trial were recruited to receive a fourth dose of MVA-B 4 years after the last immunization.

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A modified vaccinia Ankara-based HIV-1 vaccine clade B (MVA-B) has been tested for safety and immunogenicity in low-risk human immunodeficiency virus (HIV)-uninfected individuals and as a therapeutic vaccine in HIV-1-infected individuals on combined antiretroviral therapy (cART). As a therapeutic vaccine, MVA-B was safe and broadly immunogenic; however, patients still showed a viral rebound upon treatment interruption. Monocytes are an important part of the viral reservoir and several studies suggest that they are partly responsible for the chronic inflammation observed in cART-treated HIV-infected people.

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: We assessed if the increase on viral reservoir after long-term antiretroviral therapy (ART) interruption (ATI) is reversible upon ART resumption in chronic HIV-1 infected patients. Total HIV-1 DNA increased to pre-ART levels after 48 weeks of ATI to return to pre-ATI levels after 104 weeks of ART resumption. Conversely, integrated HIV-1 DNA remained elevated after ART reinitiation.

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Introduction: Peripheral blood mononuclear cells (PBMCs) are frequently used for genomic analyses, but several factors can affect the yield and integrity of nucleic acids, including the methods of cell collection and isolation. The goal of this work was to analyze the utility of systematic isolation of different immune cell subsets by immunomagnetic separation and the RNA integrity after isolated cells from samples of HIV-infected patients.

Methods: PBMC from Healthy Controls (HC, n=15), Elite Controllers (EC, n=15), Viremic Controllers (VC, n=15), Viremic Progressors (VP, n=15) and HIV-infected patients on therapy (ART, n=15) were isolated by Ficoll-Paque density gradient centrifugation.

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Background: Initiating ART during acute/recent HIV-1 infection reduces viral reservoir formation. It has been proposed that, during this phase, the size of the viral reservoir could be further reduced by the association of immunomodulatory therapy with ART. Contradictory results have emerged, however, from two trials evaluating the impact on immune recovery and the viral reservoir of adding cyclosporine A to ART during primary HIV-1 infection.

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Background: The development of a prophylactic vaccine against HIV-1 has so far not been successful. Therefore, attention has shifted more and more toward the development of novel therapeutic vaccines. Here, we evaluated a new mRNA-based therapeutic vaccine against HIV-1-encoding activation signals (TriMix: CD40L + CD70 + caTLR4) combined with rationally selected antigenic sequences [HIVACAT T-cell immunogen (HTI)] sequence: comprises 16 joined fragments from Gag, Pol, Vif, and Nef).

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Background: The relationship between host microRNAs (miRNA), viral control and immune response has not yet been elucidated in the field of HIV. The aim of this study was to assess the differential miRNA profile in CD8+ T-cells between HIV-infected individuals who differ in terms of viral replication control and immune response.

Methods: miRNA profile from resting and CD3/CD28-stimulated CD8+ T-cells from uninfected individuals (HIV-, n = 11), Elite Controllers (EC, n = 15), Viremic Controllers (VC, n = 15), Viremic Progressors (VP, n = 13) and HIV-infected patients on therapy (ART, n = 14) was assessed using Affymetrix miRNA 3.

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Unlabelled: HIV-1-specific immune responses induced by a dendritic cell (DC)-based therapeutic vaccine might have some effect on the viral reservoir. Patients on combination antiretroviral therapy (cART) were randomized to receive DCs pulsed with autologous HIV-1 (n = 24) (DC-HIV-1) or nonpulsed DCs (n = 12) (DC-control). We measured the levels of total and integrated HIV-1 DNA in CD4 T cells isolated from these patients at 6 time points: before any cART; before the first cART interruption, which was at 56 weeks before the first immunization to isolate virus for pulsing DCs; before and after vaccinations (VAC1 and VAC2); and at weeks 12 and 48 after the second cART interruption.

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Background: Although virus-specific responses are rarely detected by conventional approaches, we report here the detection of T-cell responses in HIV-exposed seronegative (HESN) patients by two distinct assays.

Methods: HIV-specific T-cell responses were analyzed by enzyme-linked immunospot in peripheral blood mononuclear cells from HESN patients after a 48-h co-culture with boosted dendritic cells. Additionally, a boosted flow cytometry approach was used to capture antiviral T-cell responses.

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Despite the availability of effective combined antiretroviral treatment, many patients still present with advanced HIV infection, often accompanied by an AIDS-defining disease. A subgroup of patients starting antiretroviral treatment under these clinical conditions may experience paradoxical worsening of their disease as a result of an exaggerated immune response towards an active (but also subclinical) infectious agent, despite an appropriate virological and immunological response to the treatment. This clinical condition, known as immune reconstitution inflammatory syndrome, may cause significant morbidity and even mortality if it is not promptly recognized and treated.

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Background: Few randomized clinical trials have investigated antiretroviral regimens in very advanced HIV-1-infected patients. The objective was to study the immune reconstitution in very immunosuppressed antiretroviral-naive, HIV-1-infected individuals by comparing an efavirenz-based regimen with 2 ritonavir-boosted protease inhibitor regimens.

Methods: Randomized, controlled, open-label, multicenter clinical trial.

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Objectives: The safety, immunogenicity, impact on the latent reservoir and rebound of viral load after therapeutic HIV-1 vaccination with recombinant modified vaccinia Ankara-based (MVA-B) HIV-1 vaccine expressing monomeric gp120 and the fused Gag-Pol-Nef polyprotein of clade B with or without a drug to reactivate latent HIV-1 (disulfiram) were assessed.

Methods: HIV-1-infected patients were randomized to receive three injections of MVA-B (n = 20) or placebo (n = 10). Twelve patients (eight who received vaccine and four who were given placebo) received a fourth dose of MVA-B followed by 3 months of disulfiram.

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Introduction: Monotherapy with protease-inhibitors (MPI) may be an alternative to cART for HIV treatment. We assessed the impact of this strategy on immune activation, bacterial translocation and inflammation.

Methods: We performed a cross-sectional study comparing patients on successful MPI (n=40) with patients on cART (n=20).

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Background: The emerging relationship between microRNAs (miRNA) and viral-control is a topic of interest in the field of HIV. Host-genome might play an important role in the control of viremia. The aim of this study was to assess the specific miRNA profile that could contribute to the control of HIV replication in Elite Controllers.

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Background: Generation of new reagents that can be used to screen or monitor HIV-1-specific responses constituted an interesting field in the development of HIV vaccines to improve their efficacy.

Methods: We have evaluated the specific T cell response against different types of NL4-3 virions (including NL4-3 aldrithiol-2 treated, NL4-3/ΔRT and R5 envelopes: NL4-3/ΔRT/ΔEnv[AC10] and NL4-3/ΔRT/ΔEnv[Bal]) and against pools of overlapping peptides (15 mer) encompassing the HIV-1 Gag and Nef regions. Cryopreserved PBMC from a subset of 69 chronic asymptomatic HIV positive individuals have been employed using different techniques including IFN-γ ELISPOT assay, surface activation markers and intracellular cytokine staining (ICS) by flow cytometry.

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Article Synopsis
  • T cell antigen receptors (TCR) in αβ and γδ T lymphocytes are thought to assemble similarly in humans, involving specific dimer pairs; CD3δε, CD3γε, and ζζ homodimers.
  • Researchers tested this by analyzing surface TCR expression in T cells from individuals with mutations affecting CD3γ or CD3δ proteins, finding that γδ TCR expression was more impacted by reduced CD3γ levels than αβ TCR expression.
  • The findings suggest that there are different structural constraints in the assembly of αβ and γδ TCRs, leading to distinct responses to changes in CD3γ protein availability, prompting a revision of the existing TCR assembly model.
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Combination antiretroviral therapy (cART) greatly improves survival and quality of life of HIV-1-infected patients; however, cART must be continued indefinitely to prevent viral rebound and associated disease progression. Inducing HIV-1-specific immune responses with a therapeutic immunization has been proposed to control viral replication after discontinuation of cART as an alternative to "cART for life." We report safety, tolerability, and immunogenicity results associated with a control of viral replication for a therapeutic vaccine using autologous monocyte-derived dendritic cells (MD-DCs) pulsed with autologous heat-inactivated whole HIV.

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