Safety and immunogenicity of Ad26.COV2.S in adults: A randomised, double-blind, placebo-controlled Phase 2a dose-finding study

BACKGROUND: A single dose of Ad26.COV2.S is well-tolerated and effective in preventing moderate-to-severe disease outcomes due to COVID-19. We evaluated the impact of dose level, number of doses, and dose interval on immunogenicity, reactogenicity, and safety of Ad26.COV2.S in adults. Anamnestic responses were also explored. METHODS: This randomised, double-blind, placebo-controlled, Phase 2a study was conducted in adults aged 18-55 years and ≥ 65 years (NCT04535453). Four dose levels (1.25 × 10 10, 2.5 × 10 10, 5 × 10 10, and 1 × 10 11 viral particles [vp], single and 2-dose schedules, and dose intervals of 56 and 84 days, were assessed. Four or 6 months post-primary vaccination, Ad26.COV2.S 1.25 × 10 10 vp was given to evaluate anamnestic responses. Humoral and cell-mediated immune responses were measured. Reactogenicity and safety were assessed in all participants. RESULTS: All Ad26.COV2.S schedules induced humoral responses with evidence of a dose response relationship. A single dose of Ad26.COV2.S (5 × 10 10 vp) induced antibody and cellular immune responses that persisted for up to at least 6 months. In the 2-dose regimens, antibody responses were higher than 1-dose regimens at comparable dose levels, and the magnitude of the immune response increased when the interval between doses was increased (84 days vs 56 days). Rapid, marked immune responses were observed in all groups after vaccine antigen exposure indicating immune memory. Durable immune responses were observed in all groups for up to at least 6 months post-antigen exposure. Strong and consistent correlations between neutralising and binding antibodies were observed CD4 + and CD8 + T cell responses were similar after all regimens. Reactogenicity within 7 days post-vaccination tended to be dose-related. CONCLUSION: The study supports the primary, single dose schedule with Ad26.COV2.S at 5 × 10 10 vp and homologous booster vaccination after a 6 month interval. Rapid and marked responses to vaccine antigen exposure indicate induction of immune memory by 1- and 2-dose primary vaccination

Immunogenicity of Ad26.COV2.S vaccine against SARS-CoV-2 variants in humans

The Ad26.COV2.S vaccine1–3 has demonstrated clinical efficacy against symptomatic COVID-19, including against the B.1.351 variant that is partially resistant to neutralizing antibodies1. However, the immunogenicity of this vaccine in humans against SARS-CoV-2 variants of concern remains unclear. Here we report humoral and cellular immune responses from 20 Ad26.COV2.S vaccinated individuals from the COV1001 phase 1/2 clinical trial2 against the original SARS-CoV-2 strain WA1/2020 as well as against the B.1.1.7, CAL.20C, P.1., and B.1.351 variants of concern. Ad26.COV2.S induced median pseudovirus neutralizing antibody titers that were 5.0- and 3.3-fold lower against the B.1.351 and P.1 variants, respectively, as compared with WA1/2020 on day 71 following vaccination. Median binding antibody titers were 2.9- and 2.7-fold lower against the B.1.351 and P.1 variants, respectively, as compared with WA1/2020. Antibody-dependent cellular phagocytosis, complement deposition, and NK cell activation responses were largely preserved against the B.1.351 variant. CD8 and CD4 T cell responses, including central and effector memory responses, were comparable among the WA1/2020, B.1.1.7, B.1.351, P.1, and CAL.20C variants. These data show that neutralizing antibody responses induced by Ad26.COV2.S were reduced against the B.1.351 and P.1 variants, but functional non-neutralizing antibody responses and T cell responses were largely preserved against SARS-CoV-2 variants. These findings have implications for vaccine protection against SARS-CoV-2 variants of concern

Régulation de l'expression et de la fonction du CFTR par l'élastase du neutrophile et l'élastace B de Pseudomonas aeruginosa

PARIS7-Bibliothèque centrale (751132105) / SudocSudocFranceF

Quand les cellules iNKT partent au charbon : nouvelles pistes thérapeutiques

International audienc

CytoGLMM:conditional differential analysis for flow and mass cytometry experiments

BACKGROUND: Flow and mass cytometry are important modern immunology tools for measuring expression levels of multiple proteins on single cells. The goal is to better understand the mechanisms of responses on a single cell basis by studying differential expression of proteins. Most current data analysis tools compare expressions across many computationally discovered cell types. Our goal is to focus on just one cell type. Our narrower field of application allows us to define a more specific statistical model with easier to control statistical guarantees. RESULTS: Differential analysis of marker expressions can be difficult due to marker correlations and inter-subject heterogeneity, particularly for studies of human immunology. We address these challenges with two multiple regression strategies: a bootstrapped generalized linear model and a generalized linear mixed model. On simulated datasets, we compare the robustness towards marker correlations and heterogeneity of both strategies. For paired experiments, we find that both strategies maintain the target false discovery rate under medium correlations and that mixed models are statistically more powerful under the correct model specification. For unpaired experiments, our results indicate that much larger patient sample sizes are required to detect differences. We illustrate the CytoGLMM R package and workflow for both strategies on a pregnancy dataset. CONCLUSION: Our approach to finding differential proteins in flow and mass cytometry data reduces biases arising from marker correlations and safeguards against false discoveries induced by patient heterogeneity

Toll-like receptor 5 (TLR5), IL-1β secretion, and asparagine endopeptidase are critical factors for alveolar macrophage phagocytosis and bacterial killing.

International audienceA deficit in early clearance of Pseudomonas aeruginosa (P. aeruginosa) is crucial in nosocomial pneumonia and in chronic lung infections. Few studies have addressed the role of Toll-like receptors (TLRs), which are early pathogen associated molecular pattern receptors, in pathogen uptake and clearance by alveolar macrophages (AMs). Here, we report that TLR5 engagement is crucial for bacterial clearance by AMs in vitro and in vivo because unflagellated P. aeruginosa or different mutants defective in TLR5 activation were resistant to AM phagocytosis and killing. In addition, the clearance of PAK (a wild-type P. aeruginosa strain) by primary AMs was causally associated with increased IL-1β release, which was dramatically reduced with PAK mutants or in WT PAK-infected primary TLR5(-/-) AMs, demonstrating the dependence of IL-1β production on TLR5. We showed that this IL-1β production was important in endosomal pH acidification and in inducing the killing of bacteria by AMs through asparagine endopeptidase (AEP), a key endosomal cysteine protease. In agreement, AMs from IL-1R1(-/-) and AEP(-/-) mice were unable to kill P. aeruginosa. Altogether, these findings demonstrate that TLR5 engagement plays a major role in P. aeruginosa internalization and in triggering IL-1β formation

Influence of Cationic Ordering on the Lattice Dynamics of Monoclinic Cu₅Sn₂S₇ and Cubic Cu₅Sn₂S_6.65Cl_0.35 Sulfides

International audienceCu2SnS3 is the parent compound of a series of phases in the Cu2+xSn1-xS3 section (0 <= x <= 0.15) of the ternary Cu-Sn-S phase diagram, the crystal structure of which can be controlled by varying the synthesis process and/or through a fine-tuning of the chemical composition. Despite being structurally close to the sphalerite structure, the thermal transport of these compounds is strongly dependent on the exact lattice symmetry and degree of atomic disorder. Here, we investigate the lattice dynamics of the monoclinic ordered Cu5Sn2S7 (space group C2) and cubic disordered Cu5Sn2S6.65Cl0.35 (space group F-43m) compounds by temperature-dependent powder inelastic neutron scattering (INS). In both cases, the INS spectra feature low-energy optical modes mostly weighed by the thermal motion of Cu atoms. The response of the INS spectra of Cu5Sn2S6.65Cl0.35 to temperature variations is indicative of quasi-harmonic behavior. Combined with analyses of the low-temperature specific heat, these findings show that the significant lowering of the lattice thermal conductivity in cubic Cu5Sn2S6.65Cl0.35 is due to a reduced phonon mean free path tied to the increased level of disorder in the unit cell. These results highlight how the stabilization of highly-symmetric, yet strongly disordered crystal structures akin to those observed in high-entropy alloys, can lead to a drastic reduction in the heat transport, offering an effective approach to design high-performance thermoelectric sulfides