BNT162b2 vaccine induces neutralizing antibodies and poly-specific T cells in humans.

BNT162b2, a nucleoside-modified mRNA formulated in lipid nanoparticles that encodes the SARS-CoV-2 spike glycoprotein (S) stabilized in its prefusion conformation, has demonstrated 95% efficacy in preventing COVID-191. Here we extend a previous phase-I/II trial report2 by presenting data on the immune response induced by BNT162b2 prime-boost vaccination from an additional phase-I/II trial in healthy adults (18-55 years old). BNT162b2 elicited strong antibody responses: at one week after the boost, SARS-CoV-2 serum geometric mean 50% neutralizing titres were up to 3.3-fold above those observed in samples from individuals who had recovered from COVID-19. Sera elicited by BNT162b2 neutralized 22 pseudoviruses bearing the S of different SARS-CoV-2 variants. Most participants had a strong response of IFNγ+ or IL-2+ CD8+ and CD4+ T helper type 1 cells, which was detectable throughout the full observation period of nine weeks following the boost. Using peptide-MHC multimer technology, we identified several BNT162b2-induced epitopes that were presented by frequent MHC alleles and conserved in mutant strains. One week after the boost, epitope-specific CD8+ T cells of the early-differentiated effector-memory phenotype comprised 0.02-2.92% of total circulating CD8+ T cells and were detectable (0.01-0.28%) eight weeks later. In summary, BNT162b2 elicits an adaptive humoral and poly-specific cellular immune response against epitopes that are conserved in a broad range of variants, at well-tolerated doses.

COVID-19 vaccine BNT162b1 elicits human antibody and TH1 T cell responses.

An effective vaccine is needed to halt the spread of the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) pandemic. Recently, we reported safety, tolerability and antibody response data from an ongoing placebo-controlled, observer-blinded phase I/II coronavirus disease 2019 (COVID-19) vaccine trial with BNT162b1, a lipid nanoparticle-formulated nucleoside-modified mRNA that encodes the receptor binding domain (RBD) of the SARS-CoV-2 spike protein1. Here we present antibody and T cell responses after vaccination with BNT162b1 from a second, non-randomized open-label phase I/II trial in healthy adults, 18-55 years of age. Two doses of 1-50 µg of BNT162b1 elicited robust CD4+ and CD8+ T cell responses and strong antibody responses, with RBD-binding IgG concentrations clearly above those seen in serum from a cohort of individuals who had recovered from COVID-19. Geometric mean titres of SARS-CoV-2 serum-neutralizing antibodies on day 43 were 0.7-fold (1-µg dose) to 3.5-fold (50-µg dose) those of the recovered individuals. Immune sera broadly neutralized pseudoviruses with diverse SARS-CoV-2 spike variants. Most participants had T helper type 1 (TH1)-skewed T cell immune responses with RBD-specific CD8+ and CD4+ T cell expansion. Interferon-γ was produced by a large fraction of RBD-specific CD8+ and CD4+ T cells. The robust RBD-specific antibody, T cell and favourable cytokine responses induced by the BNT162b1 mRNA vaccine suggest that it has the potential to protect against COVID-19 through multiple beneficial mechanisms.

TG4010 immunotherapy and first-line chemotherapy for advanced non-small-cell lung cancer (TIME): results from the phase 2b part of a randomised, double-blind, placebo-controlled, phase 2b/3 trial.

BACKGROUND: MUC1 is a tumour-associated antigen expressed by many solid tumours, including non-small-cell lung cancer. TG4010 is a modified vaccinia Ankara expressing MUC1 and interleukin 2. In a previous study, TG4010 combined with chemotherapy showed activity in non-small-cell lung cancer and the baseline value of CD16, CD56, CD69 triple-positive activated lymphocytes (TrPAL) was shown to be potentially predictive of TG4010 efficacy. In this phase 2b part of the phase 2b/3 TIME trial, we further assess TG4010 in combination with first-line chemotherapy and use of the TrPAL biomarker in this setting. METHODS: In this phase 2b part of a randomised, double-blind, placebo-controlled, phase 2b/3 trial, we recruited previously untreated patients aged 18 years or older with stage IV non-small-cell lung cancer without a known activating EGFR mutation and with MUC1 expression in at least 50% of tumoural cells. Patients were randomly allocated (1:1) by an external service provider to subcutaneous injections of 10(8) plaque-forming units of TG4010 or placebo from the beginning of chemotherapy every week for 6 weeks and then every 3 weeks up to progression, discontinuation for any reason, or toxic effects, stratified according to baseline value of TrPAL (≤ or > the upper limit of normal [ULN]) and, in addition, a dynamic minimisation procedure was used, taking into account chemotherapy regimen, histology, addition or not of bevacizumab, performance status, and centre. Patients, site staff, monitors, the study funder, data managers, and the statistician were masked to treatment identity. The primary endpoint was progression-free survival, assessed every 6 weeks, to validate the predictive value of the TrPAL biomarker. If patients with TrPAL values of less than or equal to the ULN had a Bayesian probability of more than 95% that the true hazard ratio (HR) for progression-free survival was less than 1, and if those with TrPAL values of greater than the ULN had a probability of more than 80% that the true HR for progression-free survival was more than 1, the TrPAL biomarker would be validated. We did primary analyses in the intention-to-treat population and safety analyses in those who had received at least one dose of study drug and had at least one valid post-baseline safety assessment. Monitors, site staff, and patients are still masked to treatment assignment. This trial is registered with ClinicalTrials.gov, number NCT01383148. FINDINGS: Between April 10, 2012, and Sept 12, 2014, we randomly allocated 222 patients (TG4010 and chemotherapy 111 [50%]; placebo and chemotherapy 111 [50%]). In the whole population, median progression-free survival was 5·9 months (95% CI 5·4-6·7) in the TG4010 group and 5·1 months (4·2-5·9) in the placebo group (HR 0·74 [95% CI 0·55-0·98]; one-sided p=0·019). In patients with TrPAL values of less than or equal to the ULN, the HR for progression-free survival was 0·75 (0·54-1·03); the posterior probability of the HR being less than 1 was 98·4%, and thus the primary endpoint was met. In patients with TrPAL values of greater than the ULN, the HR for progression-free survival was 0·77 (0·42-1·40); the posterior probability of the HR being greater than 1 was 31·3%, and the primary endpoint was not met. We noted grade 1-2 injection-site reactions in 36 (33%) of 110 patients in the TG4010 group versus four (4%) of 107 patients in the placebo group. We noted no grade 3 or 4 nor serious adverse events deemed to be related to TG4010 only. Four (4%) patients presented grade 3 or 4 adverse events related to TG4010 and other study treatments (chemotherapy or bevacizumab) versus 11 (10%) in the placebo group. No serious adverse event was related to the combination of TG4010 with other study treatments. The most frequent severe adverse events were neutropenia (grade 3 29 [26%], grade 4 13 [12%] in the TG4010 group vs grade 3 22 [21%], grade 4 11 [10%] in the placebo group), anaemia (grade 3 12 [11%] vs grade 3 16 [15%]), and fatigue (grade 3 12 [11%], grade 5 one [1%] vs grade 3 13 [12%]; no grade 4 events). INTERPRETATION: TG4010 plus chemotherapy seems to improve progression-free survival relative to placebo plus chemotherapy. These data support the clinical value of the TrPAL biomarker in this clinical setting; because the primary endpoint was met, the trial is to continue into the phase 3 part. FUNDING: Transgene, Avancées Diagnostiques pour de Nouvelles Approches Thérapeutiques (ADNA), and OSEO.

Bacterial iron transport: coordination properties of azotobactin, the highly fluorescent siderophore of Azotobacter vinelandii.

Azotobacter vinelandii, a nitrogen-fixing soil bacterium, secretes in iron deficiency azotobactin delta, a highly fluorescent pyoverdin-like chromopeptidic hexadentate siderophore. The chromophore, derived from 2,3-diamino-6,7 dihydroxyquinoline, is bound to a peptide chain of 10 amino acids: (L)-Asp-(D)-Ser-(L)-Hse-Gly-(D)-beta-threo-HOAsp-(L)-Ser-(D)-Cit-(L)-Hse-(L)-Hse lactone-(D)-N(delta)-Acetyl, N(delta)-HOOrn. Azotobactin delta has three different iron(III) binding sites which are one hydroxamate group at the C-terminal end of the peptidic chain (N(delta)-Acetyl, N(delta)-HOOrn), one alpha-hydroxycarboxylic function in the middle of the chain (beta-threo-hydroxyaspartic acid), and one catechol group on the chromophore. The coordination properties of its iron(III) and iron(II) complexes were measured by spectrophotometry, potentiometry, and voltammetry after the determination of the acid-base functions of the uncomplexed free siderophore. Strongly negatively charged ferric species were observed at neutral p[H]'s corresponding to a predominant absolute configuration Lambda of the ferric complex in solution as deduced from CD measurements. The presence of an alpha-hydroxycarboxylic chelating group does not decrease the stability of the iron(III) complex when compared to the main trishydroxamate siderophores or to pyoverdins. The value of the redox potential of ferric azotobactin is highly consistent with a reductive step by physiological reductants for the iron release. Formation and dissociation kinetics of the azotobactin delta ferric complex point out that both ends of this long siderophore chain get coordinated to Fe(III) before the middle. The most striking result provided by fluorescence measurements is the lasting quenching of the fluorophore in the course of the protonation of the ferric azotobactin delta complex. Despite the release of the hydroxyacid and of the catechol, the fluorescence remains indeed quenched, when iron(III) is bound only to the hydroxamic acid, suggesting a folded conformation at this stage, around the metal ion, in contrast to the unfolded species observed for other siderophores such as ferrioxamine or pyoverdin PaA.

Intramolecular Ligand Hydroxylation: Mechanistic High-Pressure Studies on the Reaction of a Dinuclear Copper(I) Complex with Dioxygen.

We provide a mechanistic study of a monooxygenase model system and detail low-temperature stopped-flow kinetics studies in acetone as solvent, employing both the use of rapid-scanning diode-array observation and variable high-pressure (20-100 MPa) techniques. The dicopper(I) complex employed is [Cu(2)(H-XYL-H)](2+) (1), with the H-XYL-H ligand wherein a m-xylyl group links two bis[2-(2-pyridyl)ethyl]amine units. This reacts with O(2) reversibly (k(1)/k(-)(1)) giving a peroxo-dicopper(II) intermediate [Cu(2)(H-XYL-H)(O(2))](2+) (2), which thereupon irreversibly (k(2)) reacts by oxygen atom insertion (i.e., hydroxylation) of the xylyl group, producing [Cu(2)(H-XYL-O(-))(OH)](2+) (3). Activation parameters are as follows: k(1), DeltaH() = 2.1 +/- 0.7 kJ/mol, DeltaS() = -174 +/- 3 J/(K mol); k(-)(1), DeltaH() = 80.3 +/- 0.8 kJ/mol, DeltaS() = 77 +/- 3 J/(K mol); k(2), DeltaH() = 58.2 +/- 0.2 kJ/mol, DeltaS() = -5.8 +/- 0.9 J/(K mol). These values are similar to values obtained in a previous study in dichloromethane. At low temperatures and higher concentrations, the situation in acetone is complicated by a pre-equilibrium of 1 to an isomer form. The present study provides the first determination of activation volumes for individual steps in copper monooxygenase reactions. The data and analysis provide that DeltaV()(k(1)) = -15 +/- 2.5 cm(3)/mol and DeltaV()(k(-)(1)) = +4.4 +/- 0.5 cm(3)/mol for formation and dissociation of 2, respectively, while DeltaV()(k(2)) = -4.1 +/- 0.7 cm(3)/mol; a volume profile for the overall reaction has been constructed. The significance of the findings in the present study is described, and the results are compared to those for other systems.