A contact binary satellite of the asteroid (152830) Dinkinesh.

Asteroids with diameters less than about 5 km have complex histories because they are small enough for radiative torques (that is, YORP, short for the Yarkovsky-O'Keefe-Radzievskii-Paddack effect)1 to be a notable factor in their evolution2. (152830) Dinkinesh is a small asteroid orbiting the Sun near the inner edge of the main asteroid belt with a heliocentric semimajor axis of 2.19 AU; its S-type spectrum3,4 is typical of bodies in this part of the main belt5. Here we report observations by the Lucy spacecraft6,7 as it passed within 431 km of Dinkinesh. Lucy revealed Dinkinesh, which has an effective diameter of only 720 m, to be unexpectedly complex. Of particular note is the presence of a prominent longitudinal trough overlain by a substantial equatorial ridge and the discovery of the first confirmed contact binary satellite, now named (152830) Dinkinesh I Selam. Selam consists of two near-equal-sized lobes with diameters of 210 m and 230 m. It orbits Dinkinesh at a distance of 3.1 km with an orbital period of about 52.7 h and is tidally locked. The dynamical state, angular momentum and geomorphologic observations of the system lead us to infer that the ridge and trough of Dinkinesh are probably the result of mass failure resulting from spin-up by YORP followed by the partial reaccretion of the shed material. Selam probably accreted from material shed by this event.

The internal structure of Eris inferred from its spin and orbit evolution.

The large Kuiper Belt object Eris is tidally locked to its small companion Dysnomia. Recently obtained bounds on the mass of Dysnomia demonstrate that Eris must be unexpectedly dissipative for it to have despun over the age of the solar system. Here, we show that Eris must have differentiated into an ice shell and rocky core to explain the dissipation. We further demonstrate that Eris's ice shell must be convecting to be sufficiently dissipative, which distinguishes it from Pluto's conductive shell. The difference is likely due to Eris's apparent depletion in volatiles compared with Pluto, perhaps as the result of a more energetic impact.

The distribution of CO2 on Europa indicates an internal source of carbon.

Jupiter's moon Europa has a subsurface ocean, the chemistry of which is largely unknown. Carbon dioxide (CO2) has previously been detected on the surface of Europa, but it was not possible to determine whether it originated from subsurface ocean chemistry, was delivered by impacts, or was produced on the surface by radiation processing of impact-delivered material. We mapped the distribution of CO2 on Europa using observations obtained with the James Webb Space Telescope (JWST). We found a concentration of CO2 within Tara Regio, a recently resurfaced terrain. This indicates that the CO2 is derived from an internal carbon source. We propose that the CO2 formed in the internal ocean, although we cannot rule out formation on the surface through radiolytic conversion of ocean-derived organics or carbonates.

Profiling the Biophysical Developability Properties of Common IgG1 Fc Effector Silencing Variants.

Therapeutic antibodies represent the most significant modality in biologics, with around 150 approved drugs on the market. In addition to specific target binding mediated by the variable fragments (Fvs) of the heavy and light chains, antibodies possess effector functions through binding of the constant region (Fc) to Fcγ receptors (FcγR), which allow immune cells to attack and kill target cells using a variety of mechanisms. However, for some applications, including T-cell-engaging bispecifics, this effector function is typically undesired. Mutations within the lower hinge and the second constant domain (CH2) of IgG1 that comprise the FcγR binding interface reduce or eliminate effector function ("Fc silencing") while retaining binding to the neonatal Fc receptor (FcRn), important for normal antibody pharmacokinetics (PKs). Comprehensive profiling of biophysical developability properties would benefit the choice of constant region variants for development. Here, we produce a large panel of representative mutations previously described in the literature and in many cases in clinical or approved molecules, generate select combinations thereof, and characterize their binding and biophysical properties. We find that some commonly used CH2 mutations, including D265A and P331S, are effective in reducing binding to FcγR but significantly reduce stability, promoting aggregation, particularly under acidic conditions commonly employed in manufacturing. We highlight mutation sets that are particularly effective for eliminating Fc effector function with the retention of WT-like stability, including L234A, L235A, and S267K (LALA-S267K), L234A, L235E, and S267K (LALE-S267K), L234A, L235A, and P329A (LALA-P329A), and L234A, L235E, and P329G (LALE-P329G).

Hydrogen peroxide at the poles of Ganymede.

Ganymede is the only satellite in the solar system known to have an intrinsic magnetic field. Interactions between this field and the Jovian magnetosphere are expected to funnel most of the associated impinging charged particles, which radiolytically alter surface chemistry across the Jupiter system, to Ganymede's polar regions. Using observations obtained with JWST as part of the Early Release Science program exploring the Jupiter system, we report the discovery of hydrogen peroxide, a radiolysis product of water ice, specifically constrained to the high latitudes. This detection directly implies radiolytic modification of the polar caps by precipitation of Jovian charged particles along partially open field lines within Ganymede's magnetosphere. Stark contrasts between the spatial distribution of this polar hydrogen peroxide, those of Ganymede's other radiolytic oxidants, and that of hydrogen peroxide on neighboring Europa have important implications for understanding water-ice radiolysis throughout the solar system.

Complex organosulfur molecules on comet 67P: Evidence from the ROSINA measurements and insights from laboratory simulations.

The ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis) instrument aboard the Rosetta mission revolutionized our understanding of cometary material composition. One of Rosetta's key findings is the complexity of the composition of comet 67P/Churyumov-Gerasimenko. Here, we used ROSINA data to analyze dust particles that were volatilized during a dust event in September 2016 and report the detection of large organosulfur species and an increase in the abundances of sulfurous species previously detected in the coma. Our data support the presence of complex sulfur-bearing organics on the surface of the comet. In addition, we conducted laboratory simulations that show that this material may have formed from chemical reactions that were initiated by the irradiation of mixed ices containing H2S. Our findings highlight the importance of sulfur chemistry in cometary and precometary materials and the possibility of characterizing organosulfur materials in other comets and small icy bodies using the James Webb Space Telescope.

Antibody-mediated protection against symptomatic COVID-19 can be achieved at low serum neutralizing titers.

Multiple studies of vaccinated and convalescent cohorts have demonstrated that serum neutralizing antibody (nAb) titers correlate with protection against coronavirus disease 2019 (COVID-19). However, the induction of multiple layers of immunity after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exposure has complicated the establishment of nAbs as a mechanistic correlate of protection (CoP) and hindered the definition of a protective nAb threshold. Here, we show that a half-life-extended monoclonal antibody (adintrevimab) provides about 50% protection against symptomatic COVID-19 in SARS-CoV-2-naïve adults at serum nAb titers on the order of 1:30. Vaccine modeling results support a similar 50% protective nAb threshold, suggesting that low titers of serum nAbs protect in both passive antibody prophylaxis and vaccination settings. Extrapolation of adintrevimab pharmacokinetic data suggests that protection against susceptible variants could be maintained for about 3 years. The results provide a benchmark for the selection of next-generation vaccine candidates and support the use of broad, long-acting monoclonal antibodies as alternatives or supplements to vaccination in high-risk populations.

Structure-based engineering of a novel CD3ε-targeting antibody for reduced polyreactivity.

Bispecific antibodies continue to represent a growth area for antibody therapeutics, with roughly a third of molecules in clinical development being T-cell engagers that use an anti-CD3 binding arm. CD3 antibodies possessing cross-reactivity with cynomolgus monkey typically recognize a highly electronegative linear epitope at the extreme N-terminus of CD3 epsilon (CD3ε). Such antibodies have high isoelectric points and display problematic polyreactivity (correlated with poor pharmacokinetics for monospecific antibodies). Using insights from the crystal structure of anti-Hu/Cy CD3 antibody ADI-26906 in complex with CD3ε and antibody engineering using a yeast-based platform, we have derived high-affinity CD3 antibody variants with very low polyreactivity and significantly improved biophysical developability. Comparison of these variants with CD3 antibodies in the clinic (as part of bi- or multi-specifics) shows that affinity for CD3 is correlated with polyreactivity. Our engineered CD3 antibodies break this correlation, forming a broad affinity range with no to low polyreactivity. Such antibodies will enable bispecifics with improved pharmacokinetic and safety profiles and suggest engineering solutions that will benefit the large and growing sector of T-cell engagers.

Ethical conflict: Conceptualization, measurement, and an examination of consequences.

Previous research on workplace conflict has focused on disagreements about work tasks, processes, and personal relationships. However, conflicts often involve matters of right and wrong; yet, ethical conflict is notably absent from the literature. Informed by moral convictions theory, we introduce the construct of ethical conflict, create and validate a measure of it, and explore its unique effects on workplace outcomes. Ultimately, we find that ethical conflict is a double-edged sword: It is negatively associated with team dynamics (i.e., decreased satisfaction with group, group viability, group cohesion, group psychological safety; increased negative emotions; and perceived goal difficulty) as well as group performance on a non-ethics-related task, but positively related to moral cognition (i.e., moral awareness and moral identity accessibility) and elaboration of information and perspectives during group ethical decision making. Overall, our studies provide a conceptual and empirical foundation for the future research on ethical conflict. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Broad and potent activity against SARS-like viruses by an engineered human monoclonal antibody.

The recurrent zoonotic spillover of coronaviruses (CoVs) into the human population underscores the need for broadly active countermeasures. We employed a directed evolution approach to engineer three severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies for enhanced neutralization breadth and potency. One of the affinity-matured variants, ADG-2, displays strong binding activity to a large panel of sarbecovirus receptor binding domains and neutralizes representative epidemic sarbecoviruses with high potency. Structural and biochemical studies demonstrate that ADG-2 employs a distinct angle of approach to recognize a highly conserved epitope that overlaps the receptor binding site. In immunocompetent mouse models of SARS and COVID-19, prophylactic administration of ADG-2 provided complete protection against respiratory burden, viral replication in the lungs, and lung pathology. Altogether, ADG-2 represents a promising broad-spectrum therapeutic candidate against clade 1 sarbecoviruses.

An Engineered Antibody with Broad Protective Efficacy in Murine Models of SARS and COVID-19.

The recurrent zoonotic spillover of coronaviruses (CoVs) into the human population underscores the need for broadly active countermeasures. Here, we employed a directed evolution approach to engineer three SARS-CoV-2 antibodies for enhanced neutralization breadth and potency. One of the affinity-matured variants, ADG-2, displays strong binding activity to a large panel of sarbecovirus receptor binding domains (RBDs) and neutralizes representative epidemic sarbecoviruses with remarkable potency. Structural and biochemical studies demonstrate that ADG-2 employs a unique angle of approach to recognize a highly conserved epitope overlapping the receptor binding site. In murine models of SARS-CoV and SARS-CoV-2 infection, passive transfer of ADG-2 provided complete protection against respiratory burden, viral replication in the lungs, and lung pathology. Altogether, ADG-2 represents a promising broad-spectrum therapeutic candidate for the treatment and prevention of SARS-CoV-2 and future emerging SARS-like CoVs.

Assessing the binding properties of the anti-PD-1 antibody landscape using label-free biosensors.

Here we describe an industry-wide collaboration aimed at assessing the binding properties of a comprehensive panel of monoclonal antibodies (mAbs) against programmed cell death protein 1 (PD-1), an important checkpoint protein in cancer immunotherapy and validated therapeutic target, with well over thirty unique mAbs either in clinical development or market-approved in the United States, the European Union or China. The binding kinetics of the PD-1/mAb interactions were measured by surface plasmon resonance (SPR) using a Carterra LSA instrument and the results were compared to data collected on a Biacore 8K. The effect of chip type on the SPR-derived binding rate constants and affinities were explored and the results compared with solution affinities from Meso Scale Discovery (MSD) and Kinetic Exclusion Assay (KinExA) experiments. When using flat chip types, the LSA and 8K platforms yielded near-identical kinetic rate and affinity constants that matched solution phase values more closely than those produced on 3D-hydrogels. Of the anti-PD-1 mAbs tested, which included a portion of those known to be in clinical development or approved, the affinities spanned from single digit picomolar to nearly 425 nM, challenging the dynamic range of our methods. The LSA instrument was also used to perform epitope binning and ligand competition studies which revealed over ten unique competitive binding profiles within this group of mAbs.

Sodium chloride on the surface of Europa.

The potential habitability of Europa's subsurface ocean depends on its chemical composition, which may be reflected in that of Europa's geologically young surface. Investigations using Galileo Near-Infrared Mapping Spectrometer data led to the prevailing view that Europa's endogenous units are rich in sulfate salts. However, recent ground-based infrared observations have suggested that, while regions experiencing sulfur radiolysis may contain sulfate salts, Europa's more pristine endogenous material may reflect a chloride-dominated composition. Chlorides have no identifying spectral features at infrared wavelengths, but develop distinct visible-wavelength absorptions under irradiation, like that experienced on the surface of Europa. Using spectra obtained with the Hubble Space Telescope, we present the detection of a 450-nm absorption indicative of irradiated sodium chloride on the surface. The feature correlates with geologically disrupted chaos terrain, suggesting an interior source. The presence of endogenous sodium chloride on the surface of Europa has important implications for our understanding of its subsurface chemistry.

Isolation and characterization of abundantly-expressed cDNAs from the Harderian gland of the garter snake (Thamnophis sirtalis: Colubridae).

The Harderian gland (HG) is an orbital structure whose proteinaceous secretions pass through the nasolacrimal duct to the vomeronasal organ (VNO). Though these three structures occur in many tetrapod vertebrates, the garter snake (Thamnophis sirtalis) is one of the few vertebrates in which the passage of the proteinaceous secretions have been experimentally shown. Secreted proteins from the HG may function as transporters for chemical signals to the VNO epithelium. To investigate the proteins being produced by the HG of the garter snake, cDNA libraries were constructed from HG mRNA, and several individual cDNAs were analyzed by sequencing, RT-qPCR, and PCR on genomic DNA. Two of the three cDNAs that were characterized are abundantly expressed only in the Harderian gland and contain putative signal sequences for secretion, which makes them candidates for transporter proteins secreted from the HG. One is a member of the large lipocalin family of proteins, based on its similarity to other members of that protein family. Many lipocalins are binding/carrier proteins for a variety of ligands. The other is a family of proteins, with five members identified so far, all of unknown structure and function and present in the garter snake genome but not in other squamate genomes.

Zika virus activates de novo and cross-reactive memory B cell responses in dengue-experienced donors.

Zika virus (ZIKV) shares a high degree of homology with dengue virus (DENV), suggesting that preexisting immunity to DENV could affect immune responses to ZIKV. We have tracked the evolution of ZIKV-induced B cell responses in three DENV-experienced donors. The acute antibody (plasmablast) responses were characterized by relatively high somatic hypermutation and a bias toward DENV binding and neutralization, implying the early activation of DENV clones. A DENV-naïve donor in contrast showed a classical primary plasmablast response. Five months after infection, the DENV-experienced donors developed potent type-specific ZIKV neutralizing antibody responses in addition to DENV cross-reactive responses. Because cross-reactive responses were poorly neutralizing and associated with enhanced ZIKV infection in vitro, preexisting DENV immunity could negatively affect protective antibody responses to ZIKV. The observed effects are epitope-dependent, suggesting that a ZIKV vaccine should be carefully designed for DENV-seropositive populations.

Labeling of neuronal morphology using custom diolistic techniques.

BACKGROUND: Diolistic labeling is increasingly utilized in neuroscience as an efficient, reproducible method for visualization of neuronal morphology. The use of lipophilic carbocyanine dyes, combined with particle-mediated biolistic delivery allows for non-toxic fluorescent labeling of multiple neurons in both living and fixed tissue. Since first described, this labeling method has been modified to fit a variety of research goals and laboratory settings. NEW METHOD: Diolistic labeling has traditionally relied on commercially available devices for the propulsion of coated micro-particles into tissue sections. Recently, laboratory built biolistic devices have been developed which allow for increased availability and customization. Here, we discuss a custom biolistic device and provide a detailed protocol for its use. RESULTS: Using custom diolistic labeling we have characterized alterations in neuronal morphology of the lateral/dentate nucleus of the rat cerebellum. Comparisons were made in developing rat pups exposed to abnormally high levels of 5-methyloxytryptamine (5-MT) pre-and postnatally. Using quantitative software; dendritic morphology, architecture, and synaptic connections, were analyzed. COMPARISON WITH EXISTING METHOD(S): The rapid nature of custom diolistics coupled with passive diffusion of dyes and compatibility with confocal microscopy, provides an unparalleled opportunity to examine features of neuronal cells at high spatial resolution in a three-dimensional tissue environment. CONCLUSIONS: While decreasing the associated costs, the laboratory-built device also overcomes many of the obstacles associated with traditional morphological labeling, to allow for reliable and reproducible neuronal labeling. The versatility of this method allows for its adaptation to a variety of laboratory settings and neuroscience related research goals.

Remediating agitation-induced antibody aggregation by eradicating exposed hydrophobic motifs.

Therapeutic antibodies must encompass drug product suitable attributes to be commercially marketed. An undesirable antibody characteristic is the propensity to aggregate. Although there are computational algorithms that predict the propensity of a protein to aggregate from sequence information alone, few consider the relevance of the native structure. The Spatial Aggregation Propensity (SAP) algorithm developed by Chennamsetty et. al. incorporates structural and sequence information to identify motifs that contribute to protein aggregation. We have utilized the algorithm to design variants of a highly aggregation prone IgG2. All variants were tested in a variety of high-throughput, small-scale assays to assess the utility of the method described herein. Many variants exhibited improved aggregation stability whether induced by agitation or thermal stress while still retaining bioactivity.

A novel path for rapid transverse communication of vestibular signals in turtle cerebellum.

Voltage-sensitive dye activity within the thin, unfoliated turtle cerebellar cortex (Cb) was recorded in vitro during eighth cranial nerve (nVIII) stimulation. Short latency responses were localized to the middle of the lateral edges of both ipsilateral and contralateral Cb [vestibulocerebellum (vCb)]. Even with a severed contralateral Cb peduncle, stimulation of the nVIII ipsilateral to the intact peduncle evoked contralateral vCb responses with a mean latency of only 0.25 ms after the ipsilateral responses, even though the distance between them was ∼ 5 mm. We investigated whether a rapidly conducting commissure exists between each vCb by stimulating one of them directly. Responses in both vCb spread sagittally, but, surprisingly, there was no sequential activation along a transverse Cb beam between them. In contrast, stimulation medial to either vCb evoked transverse beams that required ∼ 20 ms to cross the Cb. Therefore, the rapid commissural connection between each vCb is not mediated by slowly conducting parallel fibers. Also, the vCb was not strongly activated by climbing fiber stimulation, suggesting that inputs to vCb involve distinct cerebellar circuits. Responses between the two vCb remained following knife cuts through the rostral and caudal Cb along the midline, through both peduncles, and even shallow midline cuts to the middle Cb through its white matter and granule cell layer. Commissural responses were still observed only with a narrow transverse bridge between each vCb or in thick transverse Cb slices. Horseradish peroxidase transport from one vCb labeled transverse axons traveling within the Purkinje cell layer that were larger than parallel fibers and lacked varicosities. In sagittal sections, cross-section profiles of myelinated axons were observed around Purkinje cells midway between the rostral and caudal Cb. This novel pathway for transverse communication between lateral edges of turtle Cb suggests that afferents may directly conduct vestibular information rapidly across the Cb to coordinate vestibulomotor reflex behaviors.

Origin and timing of voltage-sensitive dye signals within layers of the turtle cerebellar cortex.

Optical recording techniques were applied to the turtle cerebellum to localize synchronous responses to microstimulation of its cortical layers and reveal the cerebellum's three-dimensional processing. The in vitro yet intact cerebellum was first immersed in voltage-sensitive dye and its responses while intact were compared to those measured in thick cerebellar slices. Each slice is stained throughout its depth, even though the pial half appeared darker during epi-illumination and lighter during trans-illumination. Optical responses were shown to be mediated by the voltage-sensitive dye because the evoked signals had opposite polarity for 540- and 710-nm light, but no response to 850-nm light. Molecular layer stimulation of the intact cerebellum evoked slow transverse beams. Similar beams were observed in the molecular layer of thick transverse slices but not sagittal slices. With low currents, beams in transverse slices were restricted to sublayers within the molecular layer, conducting slowly away from the stimulus site. These excitatory beams were observed nearly all the way across the turtle cerebellum, distances of 4-6mm. Microstimulation of the granule cell layer of both transverse or sagittal slices evoked a local membrane depolarization restricted to a radial wedge, but these radial responses did not activate measurable molecular layer beams in transverse slices. White matter microstimulation in sagittal slices (near the ventricular surface of the turtle cerebellum) activated the granule cell and Purkinje cell layers, but not the molecular layer. These responses were nearly synchronous, were primarily caudal to the stimulation, and were blocked by cobalt ions. Therefore, synaptic responses in all cerebellar layers contribute to optical signals recorded in intact cerebellum in vitro (Brown and Ariel, 2009). Rapid radial signaling connects a sagittally-oriented, fast-conduction system of the deep layers with the transverse-oriented, slow-conducting molecular layer, thereby permitting complex temporal processing between two tangential but orthogonal paths in the cerebellar cortex.

No sodium in the vapour plumes of Enceladus.

The discovery of water vapour and ice particles erupting from Saturn's moon Enceladus fuelled speculation that an internal ocean was the source. Alternatively, the source might be ice warmed, melted or crushed by tectonic motions. Sodium chloride (that is, salt) is expected to be present in a long-lived ocean in contact with a rocky core. Here we report a ground-based spectroscopic search for atomic sodium near Enceladus that places an upper limit on the mixing ratio in the vapour plumes orders of magnitude below the expected ocean salinity. The low sodium content of escaping vapour, together with the small fraction of salt-bearing particles, argues against a situation in which a near-surface geyser is fuelled by a salty ocean through cracks in the crust. The lack of observable sodium in the vapour is consistent with a wide variety of alternative eruption sources, including a deep ocean, a freshwater reservoir, or ice. The existing data may be insufficient to distinguish between these hypotheses.