NAV-003, a bispecific antibody targeting a unique mesothelin epitope and CD3ε with improved cytotoxicity against humoral immunosuppressed tumors.

Mesothelin (MSLN) is a cell surface protein overexpressed in a number of cancer types. Several antibody- and cellular-based MSLN targeting agents have been tested in clinical trials where their therapeutic efficacy has been moderate at best. Previous studies using antibody and Chimeric Antigen Receptor-T cells (CAR-T) strategies have shown the importance of particular MSLN epitopes for optimal therapeutic response, while other studies have found that certain MSLN-positive tumors can produce proteins that can bind to subsets of IgG1-type antibodies and suppress their immune effector activities. In an attempt to develop an improved anti-MSLN targeting agent, we engineered a humanized divalent anti-MSLN/anti-CD3ε bispecific antibody that avoids suppressive factors, can target a MSLN epitope proximal to the tumor cell surface, and is capable of effectively binding, activating, and redirecting T cells to the surface of MSLN-positive tumor cells. NAV-003 has shown significantly improved tumor cell killing against lines producing immunosuppressive proteins in vitro and in vivo. Moreover, NAV-003 demonstrated good tolerability in mice and efficacy against patient-derived mesothelioma xenografts co-engrafted with human peripheral blood mononuclear cells. Together these data support the potential for NAV-003 clinical development and human proof-of-concept studies in patients with MSLN-expressing cancers.

Preparations for a European R&D roadmap for an inertial fusion demo reactor.

A European consortium of 15 laboratories across nine nations have worked together under the EUROFusion Enabling Research grants for the past decade with three principle objectives. These are: (a) investigating obstacles to ignition on megaJoule-class laser facilities; (b) investigating novel alternative approaches to ignition, including basic studies for fast ignition (both electron and ion-driven), auxiliary heating, shock ignition, etc.; and (c) developing technologies that will be required in the future for a fusion reactor. A brief overview of these activities, presented here, along with new calculations relates the concept of auxiliary heating of inertial fusion targets, and provides possible future directions of research and development for the updated European Roadmap that is due at the end of 2020. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.

Demonstration of Scale-Invariant Rayleigh-Taylor Instability Growth in Laser-Driven Cylindrical Implosion Experiments.

Rayleigh-Taylor instability growth is shown to be hydrodynamically scale invariant in convergent cylindrical implosions for targets that varied in radial dimension and implosion timescale by a factor of 3. The targets were driven directly by laser irradiation providing a short impulse, and instability growth at an embedded aluminum interface occurs as it converges radially inward by a factor of 2.25 and decelerates on a central foam core. Late-time growth factors of 14 are observed for a single-mode m=20 azimuthal perturbation at both scales, despite the differences in laser drive conditions between the experimental facilities, consistent with predictions from radiation-hydrodynamics simulations. This platform enables detailed investigations into the limits of hydrodynamic scaling in high-energy-density systems.

Fuel gain exceeding unity in an inertially confined fusion implosion.

Ignition is needed to make fusion energy a viable alternative energy source, but has yet to be achieved. A key step on the way to ignition is to have the energy generated through fusion reactions in an inertially confined fusion plasma exceed the amount of energy deposited into the deuterium-tritium fusion fuel and hotspot during the implosion process, resulting in a fuel gain greater than unity. Here we report the achievement of fusion fuel gains exceeding unity on the US National Ignition Facility using a 'high-foot' implosion method, which is a manipulation of the laser pulse shape in a way that reduces instability in the implosion. These experiments show an order-of-magnitude improvement in yield performance over past deuterium-tritium implosion experiments. We also see a significant contribution to the yield from α-particle self-heating and evidence for the 'bootstrapping' required to accelerate the deuterium-tritium fusion burn to eventually 'run away' and ignite.

Tumor-shed antigen CA125 blocks complement-mediated killing via suppression of C1q-antibody binding.

C1q-engagement with IgG and IgM type antibodies is the initiating step of classical complement-mediated immunity. The tumor shed antigen CA125 has been reported to have immunosuppressive effects on host tumor responses as well as commercially approved and experimental monoclonal antibody (mAb)-based therapeutic agents. To better understand this effect, molecular and cellular studies were carried out testing the ability of CA125 to perturb the classical complement pathway. Here, we show that patient-derived CA125 inhibits IgG1, IgG3, and IgM-mediated complement-dependent cytotoxicity (CDC) by perturbing antibody-Fc interaction with the C1q complement-initiating protein only in those mAbs that are directly bound by CA125. This mechanism was found to impact naturally generated IgM antibodies as well as experimental and clinically approved mAbs, such as farletuzumab and rituximab, respectively. These data support a role for CA125 in humoral immune suppression and as a potential mechanism by which tumors may possibly avoid host immune responses.

FCGR2A and FCGR3A Genotypes Correlate with Farletuzumab Response in Patients with First-Relapsed Ovarian Cancer Exhibiting Low CA125.

Farletuzumab is a humanized monoclonal antibody that binds to folate receptor alpha and elicits an anti-tumor response via immune effector activity. Recent studies from a global phase 3 trial in ovarian cancer patients treated with carboplatin/taxane plus farletuzumab found that the tumor-produced CA125 protein can suppress farletuzumab function via perturbing its engagement to the activating Fc-γ receptors CD32a (FCGR2A) and CD16a (FCGR3A). Previous reports have indicated that naturally occurring polymorphisms in both of these receptors may play a role in their ability to engage therapeutic antibodies and elicit an optimal immune response via antibody-dependent cellular cytotoxicity (ADCC). In light of the importance of farletuzumab ADCC function for optimal tumor cell killing, we evaluated the frequency of FCGR2A-131H/R and FCGR3A-158V/F polymorphisms in 461 consenting patients from this global clinical study and their association with clinical outcome to placebo versus farletuzumab treatment. Here, we show that farletuzumab has enhanced binding to FCGR3A-158V high-affinity receptor and has an enhanced clinical outcome in patients with low baseline CA125 levels and at least 1 high-affinity allele of FCGR2A or FCGR3A.

Site-Specific Conjugation to Native and Engineered Lysines in Human Immunoglobulins by Microbial Transglutaminase.

The use of microbial transglutaminase (MTG) to produce site-specific antibody-drug conjugates (ADCs) has thus far focused on the transamidation of engineered acyl donor glutamine residues in an antibody based on the hypothesis that the lower specificity of MTG for acyl acceptor lysines may result in the transamidation of multiple native lysine residues, thereby yielding heterogeneous products. We investigated the utilization of native IgG lysines as acyl acceptor sites for glutamine-based acyl donor substrates. Of the approximately 80 lysines in multiple recombinant IgG monoclonal antibodies (mAbs), none were transamidated. Because recombinant mAbs lack the C-terminal Lys447 due to cleavage by carboxypeptidase B in the production cell host, we explored whether blocking the cleavage of Lys447 by the addition of a C-terminal amino acid could result in transamidation of Lys447 by a variety of acyl donor substrates. MTG efficiently transamidated Lys447 in the presence of any nonacidic, nonproline amino acid residue at position 448. Lysine scanning mutagenesis throughout the antibody further revealed several transamidation sites in both the heavy- and light-chain constant regions. Additionally, scanning mutagenesis of the hinge region in a Fab' fragment revealed sites of transamidation that were not reactive in the context of the full-length mAb. Here, we demonstrate the utility of single lysine substitutions and the C-terminal Lys447 for engineering efficient acyl acceptor sites suitable for site-specific conjugation to a range of glutamine-based acyl donor substrates.

Publisher's Note: Development of improved radiation drive environment for high foot implosions at the National Ignition Facility [Phys. Rev. Lett. 117, 225002 (2016)].

This corrects the article DOI: 10.1103/PhysRevLett.117.225002.

Longitudinal stability of asthma characteristics and biomarkers from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) study.

BACKGROUND: Asthma is a biologically heterogeneous disease and development of novel therapeutics requires understanding of pathophysiologic phenotypes. There is uncertainty regarding the stability of clinical characteristics and biomarkers in asthma over time. This report presents the longitudinal stability over 12 months of clinical characteristics and clinically accessible biomarkers from ADEPT. METHODS: Mild, moderate, and severe asthma subjects were assessed at 5 visits over 12 months. Assessments included patient questionnaires, spirometry, bronchodilator reversibility, fractional exhaled nitric oxide (FENO), and biomarkers measured in induced sputum. RESULTS: Mild (n = 52), moderate (n = 55), and severe (n = 51) asthma cohorts were enrolled from North America and Western Europe. For all clinical characteristics and biomarkers, group mean data showed no significant change from visit to visit. However, individual data showed considerable variability. FEV1/FVC ratio showed excellent reproducibility while pre-bronchodilator FEV1 and FVC were only moderately reproducible. Of note bronchodilator FEV1 reversibility showed low reproducibility, with the nonreversible phenotype much more reproducible than the reversible phenotype. The 7-item asthma control questionnaire (ACQ7) demonstrated moderate reproducibility for the combined asthma cohorts, but the uncontrolled asthma phenotype (ACQ7 > 1.5) was inconstant in mild and moderate asthma but stable in severe asthma. FENO demonstrated good reproducibility, with the FENO-low phenotype (FENO < 35 ppb) more stable than the FENO-high phenotype (FENO ≥ 35 ppb). Induced sputum inflammatory phenotypes showed marked variability across the 3 sputum samples taken over 6 months. CONCLUSIONS: The ADEPT cohort showed group stability, individual stability in some parameters e.g. low FEV1/FVC ratio, and low FENO, but marked individual variability in other clinical characteristics and biomarkers e.g. type-2 biomarkers over 12 months. This variability is possibly related to seasonal variations in climate and allergen exposure, medication changes and acute exacerbations. The implications for patient selection strategies based on clinical biomarkers may be considerable.

Late-Time Mixing Sensitivity to Initial Broadband Surface Roughness in High-Energy-Density Shear Layers.

Using a large volume high-energy-density fluid shear experiment (8.5 cm^{3}) at the National Ignition Facility, we have demonstrated for the first time the ability to significantly alter the evolution of a supersonic sheared mixing layer by controlling the initial conditions of that layer. By altering the initial surface roughness of the tracer foil, we demonstrate the ability to transition the shear mixing layer from a highly ordered system of coherent structures to a randomly ordered system with a faster growing mix layer, indicative of strong mixing in the layer at a temperature of several tens of electron volts and at near solid density. Simulations using a turbulent-mix model show good agreement with the experimental results and poor agreement without turbulent mix.

Development of Improved Radiation Drive Environment for High Foot Implosions at the National Ignition Facility.

Analyses of high foot implosions show that performance is limited by the radiation drive environment, i.e., the hohlraum. Reported here are significant improvements in the radiation environment, which result in an enhancement in implosion performance. Using a longer, larger case-to-capsule ratio hohlraum at lower gas fill density improves the symmetry control of a high foot implosion. Moreover, for the first time, these hohlraums produce reduced levels of hot electrons, generated by laser-plasma interactions, which are at levels comparable to near-vacuum hohlraums, and well within specifications. Further, there is a noteworthy increase in laser energy coupling to the hohlraum, and discrepancies with simulated radiation production are markedly reduced. At fixed laser energy, high foot implosions driven with this improved hohlraum have achieved a 1.4×increase in stagnation pressure, with an accompanying relative increase in fusion yield of 50% as compared to a reference experiment with the same laser energy.

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility.

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D_{2} and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (1230) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

Asthma characteristics and biomarkers from the Airways Disease Endotyping for Personalized Therapeutics (ADEPT) longitudinal profiling study.

BACKGROUND: Asthma is a heterogeneous disease and development of novel therapeutics requires an understanding of pathophysiologic phenotypes. The purpose of the ADEPT study was to correlate clinical features and biomarkers with molecular characteristics, by profiling asthma (NCT01274507). This report presents for the first time the study design, and characteristics of the recruited subjects. METHODS: Patients with a range of asthma severity and healthy non-atopic controls were enrolled. The asthmatic subjects were followed for 12 months. Assessments included history, patient questionnaires, spirometry, airway hyper-responsiveness to methacholine, fractional exhaled nitric oxide (FENO), and biomarkers measured in induced sputum, blood, and bronchoscopy samples. All subjects underwent sputum induction and 30 subjects/cohort had bronchoscopy. RESULTS: Mild (n = 52), moderate (n = 55), severe (n = 51) asthma cohorts and 30 healthy controls were enrolled from North America and Western Europe. Airflow obstruction, bronchodilator response and airways hyperresponsiveness increased with asthma severity, and severe asthma subjects had reduced forced vital capacity. Asthma control questionnaire-7 (ACQ7) scores worsened with asthma severity. In the asthmatics, mean values for all clinical and biomarker characteristics were stable over 12 months although individual variability was evident. FENO and blood eosinophils did not differ by asthma severity. Induced sputum eosinophils but not neutrophils were lower in mild compared to the moderate and severe asthma cohorts. CONCLUSIONS: The ADEPT study successfully enrolled asthmatics across a spectrum of severity and non-atopic controls. Clinical characteristics were related to asthma severity and in general asthma characteristics e.g. lung function, were stable over 12 months. Use of the ADEPT data should prove useful in defining biological phenotypes to facilitate personalized therapeutic approaches.

Demonstration of High Performance in Layered Deuterium-Tritium Capsule Implosions in Uranium Hohlraums at the National Ignition Facility.

We report on the first layered deuterium-tritium (DT) capsule implosions indirectly driven by a "high-foot" laser pulse that were fielded in depleted uranium hohlraums at the National Ignition Facility. Recently, high-foot implosions have demonstrated improved resistance to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot [Hurricane et al., Nature (London) 506, 343 (2014)]. Uranium hohlraums provide a higher albedo and thus an increased drive equivalent to an additional 25 TW laser power at the peak of the drive compared to standard gold hohlraums leading to higher implosion velocity. Additionally, we observe an improved hot-spot shape closer to round which indicates enhanced drive from the waist. In contrast to findings in the National Ignition Campaign, now all of our highest performing experiments have been done in uranium hohlraums and achieved total yields approaching 10^{16} neutrons where more than 50% of the yield was due to additional heating of alpha particles stopping in the DT fuel.

2D X-ray radiography of imploding capsules at the national ignition facility.

First measurements of the in-flight shape of imploding inertial confinement fusion (ICF) capsules at the National Ignition Facility (NIF) were obtained by using two-dimensional x-ray radiography. The sequence of area-backlit, time-gated pinhole images is analyzed for implosion velocity, low-mode shape and density asymmetries, and the absolute offset and center-of-mass velocity of the capsule shell. The in-flight shell is often observed to be asymmetric even when the concomitant core self-emission is round. A ∼ 15 µm shell asymmetry amplitude of the Y(40) spherical harmonic mode was observed for standard NIF ICF hohlraums at a shell radius of ∼ 200 µm (capsule at ∼ 5× radial compression). This asymmetry is mitigated by a ∼ 10% increase in the hohlraum length.

High-adiabat high-foot inertial confinement fusion implosion experiments on the national ignition facility.

This Letter reports on a series of high-adiabat implosions of cryogenic layered deuterium-tritium (DT) capsules indirectly driven by a "high-foot" laser drive pulse at the National Ignition Facility. High-foot implosions have high ablation velocities and large density gradient scale lengths and are more resistant to ablation-front Rayleigh-Taylor instability induced mixing of ablator material into the DT hot spot. Indeed, the observed hot spot mix in these implosions was low and the measured neutron yields were typically 50% (or higher) of the yields predicted by simulation. On one high performing shot (N130812), 1.7 MJ of laser energy at a peak power of 350 TW was used to obtain a peak hohlraum radiation temperature of ∼300 eV. The resulting experimental neutron yield was (2.4±0.05)×10(15) DT, the fuel ρR was (0.86±0.063) g/cm2, and the measured Tion was (4.2±0.16) keV, corresponding to 8 kJ of fusion yield, with ∼1/3 of the yield caused by self-heating of the fuel by α particles emitted in the initial reactions. The generalized Lawson criteria, an ignition metric, was 0.43 and the neutron yield was ∼70% of the value predicted by simulations that include α-particle self-heating.

Design of a high-foot high-adiabat ICF capsule for the national ignition facility.

The National Ignition Campaign's [M. J. Edwards et al., Phys. Plasmas 20, 070501 (2013)] point design implosion has achieved DT neutron yields of 7.5×10(14) neutrons, inferred stagnation pressures of 103 Gbar, and inferred areal densities (ρR) of 0.90 g/cm2 (shot N111215), values that are lower than 1D expectations by factors of 10×, 3.3×, and 1.5×, respectively. In this Letter, we present the design basis for an inertial confinement fusion capsule using an alternate indirect-drive pulse shape that is less sensitive to issues that may be responsible for this lower than expected performance. This new implosion features a higher radiation temperature in the "foot" of the pulse, three-shock pulse shape resulting in an implosion that has less sensitivity to the predicted ionization state of carbon, modestly lower convergence ratio, and significantly lower ablation Rayleigh-Taylor instability growth than that of the NIC point design capsule. The trade-off with this new design is a higher fuel adiabat that limits both fuel compression and theoretical capsule yield. The purpose of designing this capsule is to recover a more ideal one-dimensional implosion that is in closer agreement to simulation predictions. Early experimental results support our assertions since as of this Letter, a high-foot implosion has obtained a record DT yield of 2.4×10(15) neutrons (within ∼70% of 1D simulation) with fuel ρR=0.84 g/cm2 and an estimated ∼1/3 of the yield coming from α-particle self-heating.

Measurements of an ablator-gas atomic mix in indirectly driven implosions at the National Ignition Facility.

We present the first results from an experimental campaign to measure the atomic ablator-gas mix in the deceleration phase of gas-filled capsule implosions on the National Ignition Facility. Plastic capsules containing CD layers were filled with tritium gas; as the reactants are initially separated, DT fusion yield provides a direct measure of the atomic mix of ablator into the hot spot gas. Capsules were imploded with x rays generated in hohlraums with peak radiation temperatures of ∼294 eV. While the TT fusion reaction probes conditions in the central part (core) of the implosion hot spot, the DT reaction probes a mixed region on the outer part of the hot spot near the ablator-hot-spot interface. Experimental data were used to develop and validate the atomic-mix model used in two-dimensional simulations.

Indoor airborne bacterial communities are influenced by ventilation, occupancy, and outdoor air source.

Architects and engineers are beginning to consider a new dimension of indoor air: the structure and composition of airborne microbial communities. A first step in this emerging field is to understand the forces that shape the diversity of bioaerosols across space and time within the built environment. In an effort to elucidate the relative influences of three likely drivers of indoor bioaerosol diversity - variation in outdoor bioaerosols, ventilation strategy, and occupancy load - we conducted an intensive temporal study of indoor airborne bacterial communities in a high-traffic university building with a hybrid HVAC (mechanically and naturally ventilated) system. Indoor air communities closely tracked outdoor air communities, but human-associated bacterial genera were more than twice as abundant in indoor air compared with outdoor air. Ventilation had a demonstrated effect on indoor airborne bacterial community composition; changes in outdoor air communities were detected inside following a time lag associated with differing ventilation strategies relevant to modern building design. Our results indicate that both occupancy patterns and ventilation strategies are important for understanding airborne microbial community dynamics in the built environment.