Publications by authors named "Delphine Planas"

Article Synopsis
  • - First-generation monoclonal antibodies (mAbs) for COVID-19 were withdrawn due to resistance from Omicron variants, but two new mAbs, VYD222/Pemivibart and AZD3152/Sipavibart, were approved in 2024.
  • - Researchers tested these mAbs against contemporary JN.1 sublineages and found VYD222 still had moderate activity, but AZD3152 lost effectiveness against several variants.
  • - The study underscores the importance of monitoring VYD222's clinical performance and raises concerns about AZD3152's efficacy in treating infections from newer variants.
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The mechanistic target of rapamycin (mTOR) positively regulates multiple steps of the HIV-1 replication cycle. We previously reported that a 12-week supplementation of antiretroviral therapy (ART) with metformin, an indirect mTOR inhibitor used in type-2 diabetes treatment, reduced mTOR activation and HIV transcription in colon-infiltrating CD4 T cells, together with systemic inflammation in nondiabetic people with HIV-1 (PWH). Herein, we investigated the antiviral mechanisms of metformin.

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Predicting the immunogenicity of candidate vaccines in humans remains a challenge. To address this issue, we developed a lymphoid organ-chip (LO chip) model based on a microfluidic chip seeded with human PBMC at high density within a 3D collagen matrix. Perfusion of the SARS-CoV-2 spike protein mimicked a vaccine boost by inducing a massive amplification of spike-specific memory B cells, plasmablast differentiation, and spike-specific antibody secretion.

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Antibodies play a pivotal role in protecting from SARS-CoV-2 infection, but their efficacy is challenged by the continuous emergence of viral variants. In this study, we describe two broadly neutralizing antibodies cloned from the memory B cells of a single convalescent individual after infection with ancestral SARS-CoV-2. Cv2.

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Background: SARS-CoV-2 Omicron lineage contains variants with multiple sequence mutations relative to the ancestral strain particularly in the viral spike gene. These mutations are associated inter alia with loss of neutralization sensitivity to sera generated by immunization with vaccines targeting ancestral strains or prior infection with circulating (non-Omicron) variants. Here we present a comparison of vaccine formulation elicited cross neutralization responses using two different assay readouts from a subpopulation of a Phase II/III clinical trial.

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The unceasing circulation of SARS-CoV-2 leads to the continuous emergence of novel viral sublineages. Here, we isolate and characterize XBB.1, XBB.

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The mechanistic target of rapamycin (mTOR) positively regulates multiple steps of the HIV-1 replication cycle. We previously reported that a 12-weeks supplementation of antiretroviral therapy (ART) with metformin, an indirect mTOR inhibitor used in type-2 diabetes treatment, reduced mTOR activation and HIV transcription in colon-infiltrating CD4 T-cells, together with systemic inflammation in nondiabetic people with HIV-1 (PWH). Herein, we investigated the antiviral mechanisms of metformin.

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SARS-CoV-2 variants with undetermined properties have emerged intermittently throughout the COVID-19 pandemic. Some variants possess unique phenotypes and mutations which allow further characterization of viral evolution and Spike functions. Around 1,100 cases of the B.

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The unceasing circulation of SARS-CoV-2 leads to the continuous emergence of novel viral sublineages. Here, we isolated and characterized XBB.1, XBB.

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Antibodies effective against the recent Omicron sublineages are missing. By taking advantage of a multi-centric prospective cohort of immunocompromised individuals treated for mild-to-moderate COVID-19, Bruel et al. show that administration of 500 mg of sotrovimab induces serum neutralization and antibody-dependent cellular cytotoxicity of BQ.

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Article Synopsis
  • The study investigates the immune responses in long COVID patients, focusing on humoral (antibody) and CD4+ T cell responses before vaccination.
  • It includes participants who are seropositive and seronegative for antibodies against SARS-CoV-2, comparing them with individuals who recovered from COVID-19 and uninfected controls.
  • Results indicate that seronegative long COVID patients have weaker immune responses to the virus, while seropositive patients exhibit strong coordinated antiviral responses, highlighting the complexity of immune reactions in long COVID cases.
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Because SARS-CoV-2 constantly mutates to escape from the immune response, there is a reduction of neutralizing capacity of antibodies initially targeting the historical strain against emerging Variants of Concern (VoC)s. That is why the measure of the protection conferred by vaccination cannot solely rely on the antibody levels, but also requires to measure their neutralization capacity. Here we used a mathematical model to follow the humoral response in 26 individuals that received up to three vaccination doses of Bnt162b2 vaccine, and for whom both anti-S IgG and neutralization capacity was measured longitudinally against all main VoCs.

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Background: Monoclonal antibodies (mAbs) targeting the spike of SARS-CoV-2 prevent severe COVID-19. Omicron subvariants BQ.1.

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BackgroundThe risk of SARS-CoV-2 (re-)infection remains present given waning of vaccine-induced and infection-acquired immunity, and ongoing circulation of new variants.AimTo develop a method that predicts virus neutralisation and disease protection based on variant-specific antibody measurements to SARS-CoV-2 antigens.MethodsTo correlate antibody and neutralisation titres, we collected 304 serum samples from individuals with either vaccine-induced or infection-acquired SARS-CoV-2 immunity.

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Mpox virus (MPXV) caused a multi-country outbreak in non-endemic areas in 2022. Following historic success of smallpox vaccination with vaccinia virus (VACV)-based vaccines, the third generation modified vaccinia Ankara (MVA)-based vaccine was used as prophylaxis for MPXV, but its effectiveness remains poorly characterized. Here, we applied two assays to quantify neutralizing antibodies (NAbs) in sera from control, MPXV-infected, or MVA-vaccinated individuals.

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The emergence of Omicron sublineages impacts the therapeutic efficacy of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) monoclonal antibodies (mAbs). Here, we evaluate neutralization and antibody-dependent cellular cytotoxicity (ADCC) activities of 6 therapeutic mAbs against Delta, BA.2, BA.

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Background: The protective immunity against omicron following a BNT162b2 Pfizer booster dose among elderly individuals (ie, those aged >65 years) is not well characterised.

Methods: In a community-based, prospective, longitudinal cohort study taking place in France in which 75 residents from three nursing homes were enrolled, we selected 38 residents who had received a two-dose regimen of mRNA vaccine and a booster dose of Pfizer BNT162b2 vaccine. We excluded individuals that did not receive three vaccine doses or did not have available sera samples.

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Serological assays capable of measuring antibody responses induced by previous infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) have been critical tools in the response to the COVID-19 pandemic. In this study, we use bead-based multiplex assays to measure IgG and IgA antibodies and IgG avidity to five SARS-CoV-2 antigens (Spike (S), receptor-binding domain (RBD), Nucleocapsid (N), S subunit 2, and Membrane-Envelope fusion (ME)). These assays were performed in several cohorts of healthcare workers and nursing home residents, who were followed for up to eleven months after SARS-CoV-2 infection or up to six months after vaccination.

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Article Synopsis
  • * In this study, researchers found that various bat cell lines did not allow SARS-CoV-2 to infect, even when they expressed ACE2, the receptor used by the virus; infection was only possible when human ACE2 was introduced.
  • * The findings suggest that bats possess specific molecular barriers to viral replication, highlighting the importance of developing bat cellular models to better understand the evolutionary relationship between bats and coronaviruses.
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