Potent neutralization by a receptor binding domain monoclonal antibody with broad specificity for SARS-CoV-2 JN.1 and other variants.

SARS-CoV-2 continues to be a public health burden, driven in-part by its continued antigenic diversification and resulting emergence of new variants. While increasing herd immunity, current vaccines, and therapeutics have improved outcomes for some; prophylactic and treatment interventions that are not compromised by viral evolution of the Spike protein are still needed. Using a rationally designed SARS-CoV-2 Receptor Binding Domain (RBD) - ACE2 fusion protein and differential selection process with native Omicron RBD protein, we developed a recombinant human monoclonal antibody (hmAb) from a convalescent individual following SARS-CoV-2 Omicron infection. The resulting hmAb, 1301B7 potently neutralized a wide range of SARS-CoV-2 variants including the original Wuhan and more recent Omicron JN.1 strain, as well as SARS-CoV. Structure determination of the SARS-CoV-2 EG5.1 Spike/1301B7 Fab complex by cryo-electron microscopy at 3.1Å resolution demonstrates 1301B7 contacts the ACE2 binding site of RBD exclusively through its VH1-69 heavy chain, making contacts using CDRs1-3, as well as framework region 3 (FR3). Broad specificity is achieved through 1301B7 binding to many conserved residues of Omicron variants including Y501 and H505. Consistent with its extensive binding epitope, 1301B7 is able to potently diminish viral burden in the upper and lower respiratory tract and protect mice from challenge with Omicron XBB1.5 and Omicron JN.1 viruses. These results suggest 1301B7 has broad potential to prevent or treat clinical SARS-CoV-2 infections and to guide development of RBD-based universal SARS-CoV-2 prophylactic vaccines and therapeutic approaches.

LIF/JAK2/STAT1 Signaling Enhances Production of Galactose-Deficient IgA1 by IgA1-Producing Cell Lines Derived From Tonsils of Patients With IgA Nephropathy.

Introduction: Galactose-deficient IgA1 (Gd-IgA1) plays a key role in the pathogenesis of IgA nephropathy (IgAN). Tonsillectomy has been beneficial to some patients with IgAN, possibly due to the removal of tonsillar cytokine-activated cells producing Gd-IgA1. To test this hypothesis, we used immortalized IgA1-producing cell lines derived from tonsils of patients with IgAN or obstructive sleep apnea (OSA) and assessed the effect of leukemia inhibitory factor (LIF) or oncostatin M (OSM) on Gd-IgA1 production. Methods: Gd-IgA1 production was measured by lectin enzyme-linked immunosorbent assay; JAK-STAT signaling in cultured cells was assessed by immunoblotting of cell lysates; and validated by using small interfering RNA (siRNA) knock-down and small-molecule inhibitors. Results: IgAN-derived cells produced more Gd-IgA1 than the cells from patients with OSA, and exhibited elevated Gd-IgA1 production in response to LIF, but not OSM. This effect was associated with dysregulated STAT1 phosphorylation, as confirmed by STAT1 siRNA knock-down. JAK2 inhibitor, AZD1480 exhibited a dose-dependent inhibition of the LIF-induced Gd-IgA1 overproduction. Unexpectedly, high concentrations of AZD1480, but only in the presence of LIF, reduced Gd-IgA1 production in the cells derived from patients with IgAN to that of the control cells from patients with OSA. Based on modeling LIF-LIFR-gp130-JAK2 receptor complex, we postulate that LIF binding to LIFR may sequester gp130 and/or JAK2 from other pathways; and when combined with JAK2 inhibition, enables full blockade of the aberrant O-glycosylation pathways in IgAN. Conclusion: In summary, IgAN cells exhibit LIF-mediated overproduction of Gd-IgA1 due to abnormal signaling. JAK2 inhibitors can counter these LIF-induced effects and block Gd-IgA1 synthesis in IgAN.

Varying Doses of Epicutaneous Immunotherapy With Viaskin Milk vs Placebo in Children With Cow's Milk Allergy: A Randomized Clinical Trial.

Importance: No approved treatment exists for allergen-specific immunoglobulin E (IgE)-mediated cow's milk allergy (CMA), a common childhood food allergy. Objective: To assess dose, efficacy, and safety of epicutaneous immunotherapy with Viaskin milk in children with IgE-mediated CMA. Design, Setting, and Participants: A phase 1/2, 2-part, randomized, double-blind, placebo-controlled dose-ranging clinical trial in children aged 2 to 17 years with IgE-mediated CMA was conducted between November 2014 through December 2017. It took place at 17 trial sites in the US and Canada. Current CMA was confirmed by double-blind, placebo-controlled food challenge at study entry. Part A assessed the short-term safety of 150 µg, 300 µg, or 500 µg of Viaskin milk; part B evaluated the efficacy and safety of the 3 doses vs placebo over 12 months of treatment. Of the 308 screened participants with physician-diagnosed CMA, 198 met eligibility criteria (including an eliciting dose 300 mg or less) and were randomized. Intervention: Safety of Viaskin milk (150-µg, 300-µg, or 500-µg doses) was evaluated over a 3-week period (part A). In part B, 180 additional participants were randomized to receive Viaskin milk at doses of 150 µg, 300 µg, or 500 µg or placebo (1:1:1:1) for 12 months. Main Outcomes and Measures: The primary outcome was the proportion of treatment responders, defined as a 10-fold or more increase in the cumulative reactive dose of cow's milk protein (reaching at least 144 mg) or a cumulative reactive dose of cow's milk protein at 1444 mg or more at the month 12 double-blind, placebo-controlled food challenge. Results: A total of 95.5% of the randomized participants (mean [SD] age, 8 [4.17] years; 124 of 198 were male [62.6%]) completed treatment. The highest response rate was observed in participants who received Viaskin milk at the 300-µg dose with 24 of 49 responders (49.0%) overall vs 16 of 53 responders (30.2%) in the placebo group (odds ratio, 2.19; 95% CI, 0.91-5.41; P = .09), highest in the 2 to 11 years age group (22 of 38 [57.9%] vs 13 of 40 [32.5%]; P = .04). Most treatment-emergent adverse events were mild or moderate application-site reactions. One participant in the 500-µg Viaskin milk dose group experienced treatment-related anaphylaxis. Conclusions and Relevance: In this randomized clinical trial, 12 months of daily epicutaneous immunotherapy with a dose of Viaskin milk at 300 µg was associated with a statistically significant treatment response in 2- to 11-year-old children with IgE-mediated CMA. Treatment-related anaphylaxis and treatment-related discontinuation rates were low. Further research is needed to explore Viaskin milk as a viable treatment option for children with IgE-mediated CMA. Trial Registration: ClinicalTrials.gov Identifier: NCT02223182.

Comparative digital reconstruction of Pica pica and Struthio camelus and their cranial suture ontogenies.

To date, several studies describe post-hatching ontogenetic variation in birds; however, none of these studies document and compare ontogenetic variation of the entire skull in multiple avian species. Therefore, we studied ontogenetic skull variation of two bird species with very different ecologies, Pica pica, and Struthio camelus, using µCT based 3D reconstructions. For each specimen, we performed bone-by-bone segmentation in order to visualize and describe the morphological variation of each bone during ontogeny and estimated the average sutural closure of the skulls to identify different ontogenetic stages. Although bone fusion of P. pica occurs more rapidly than that of S. camelus the general sequence of bone fusion follows a similar trend from posterior to anterior, but a more detailed analysis reveals some interspecific variation in the fusion patterns. Although growth persists over a longer period in S. camelus than in P. pica and adults of the former species are significantly larger, the skull of the most mature S. camelus is still less fused than that of P. pica. Different growth and fusion patterns of the two species indicate that the interspecific ontogenetic variation could be related to heterochronic developments. Nevertheless, this hypothesis needs to be tested in a broader phylogenetic framework in order to detect the evolutionary direction of the potential heterochronic transformations.

Efficacy and safety of peanut epicutaneous immunotherapy in patients with atopic comorbidities.

Background: Co-occurring atopic conditions are common in children with peanut allergy. As such, it is important to examine the safety and efficacy of epicutaneous immunotherapy with Viaskin Peanut 250 µg patch (VP250) in peanut-allergic children with these conditions. Objective: We sought to compare efficacy and safety of VP250 versus placebo in peanut-allergic children with/without ongoing atopic conditions at baseline, including asthma, atopic dermatitis/eczema, or concomitant food allergy. Methods: A subgroup analysis of peanut-allergic children aged 4 to 11 years enrolled in PEPITES (12 months) and REALISE (6 months) randomized, placebo-controlled, phase 3 trials was conducted. The efficacy outcome measure was the difference in prespecified responder rate between placebo and VP250 groups at month 12 based on eliciting dose of peanut protein using double-blind, placebo-controlled food challenge in PEPITES. Safety profiles were evaluated by baseline concomitant disease subgroup in all randomized subjects who received 1 or more dose of the study drug in PEPITES and REALISE pooled data. Results: Responder rates were significantly (P < .05, all comparisons) greater with VP250 compared with placebo treatment regardless of whether subjects had other atopic conditions. Safety and tolerability profiles were generally similar across subgroups, with no new safety concerns detected. A trend for both higher responder rates and rates of local reactions was observed in subjects with baseline atopic dermatitis versus those without. In subjects with concomitant food allergy at baseline, higher rates of treatment-emergent adverse events, but not study discontinuations or overall rates of anaphylaxis, were observed. Conclusions: The results support the safety and efficacy of VP250 for treating peanut-allergic children with or without concomitant atopic conditions.

Current Understanding of Complement Proteins as Therapeutic Targets for the Treatment of Immunoglobulin A Nephropathy.

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis worldwide and a frequent cause of kidney failure. Currently, the diagnosis necessitates a kidney biopsy, with routine immunofluorescence microscopy revealing IgA as the dominant or co-dominant immunoglobulin in the glomerular immuno-deposits, often with IgG and sometimes IgM or both. Complement protein C3 is observed in most cases. IgAN leads to kidney failure in 20-40% of patients within 20 years of diagnosis and reduces average life expectancy by about 10 years. There is increasing clinical, biochemical, and genetic evidence that the complement system plays a paramount role in the pathogenesis of IgAN. The presence of C3 in the kidney immuno-deposits differentiates the diagnosis of IgAN from subclinical glomerular mesangial IgA deposition. Markers of complement activation via the lectin and alternative pathways in kidney-biopsy specimens are associated with disease activity and are predictive of poor outcome. Levels of select complement proteins in the circulation have also been assessed in patients with IgAN and found to be of prognostic value. Ongoing genetic studies have identified at least 30 loci associated with IgAN. Genes within some of these loci encode complement-system regulating proteins that can interact with immune complexes. The growing appreciation for the central role of complement components in IgAN pathogenesis highlighted these pathways as potential treatment targets and sparked great interest in pharmacological agents targeting the complement cascade for the treatment of IgAN, as evidenced by the plethora of ongoing clinical trials.

Discontinuous L-binding motifs in the transactivation domain of the vesicular stomatitis virus P protein are required for terminal de novo transcription initiation by the L protein.

The phospho- (P) protein, the co-factor of the RNA polymerase large (L) protein, of vesicular stomatitis virus (VSV, a prototype of nonsegmented negative-strand RNA viruses) plays pivotal roles in transcription and replication. However, the precise mechanism underlying the transcriptional transactivation by the P protein has remained elusive. Here, using an in vitro transcription system and a series of deletion mutants of the P protein, we mapped a region encompassing residues 51-104 as a transactivation domain (TAD) that is critical for terminal de novo initiation, the initial step of synthesis of the leader RNA and anti-genome/genome, with the L protein. Site-directed mutagenesis revealed that conserved amino acid residues in three discontinuous L-binding sites within the TAD are essential for the transactivation activity of the P protein or important for maintaining its full activity. Importantly, relative inhibitory effects of TAD point mutations on synthesis of the full-length leader RNA and mRNAs from the 3'-terminal leader region and internal genes, respectively, of the genome were similar to those on terminal de novo initiation. Furthermore, any of the examined TAD mutations did not alter the gradient pattern of mRNAs synthesized from internal genes, nor did they induce the production of readthrough transcripts. These results suggest that these TAD mutations impact mainly terminal de novo initiation but rarely other steps (e.g., elongation, termination, internal initiation) of single-entry stop-start transcription. Consistently, the mutations of the essential or important amino acid residues within the P TAD were lethal or deleterious to VSV replication in host cells. IMPORTANCE RNA-dependent RNA polymerase L proteins of nonsegmented negative-strand RNA viruses belonging to the Mononegavirales order require their cognate co-factor P proteins or their counterparts for genome transcription and replication. However, exact roles of these co-factor proteins in modulating functions of L proteins during transcription and replication remain unknown. In this study, we revealed that three discrete L-binding motifs within a transactivation domain of the P protein of vesicular stomatitis virus, a prototypic nonsegmented negative-strand RNA virus, are required for terminal de novo initiation mediated by the L protein, which is the first step of synthesis of the leader RNA as well as genome/anti-genome.

B cell and antibody targeting of transplant alloantigen epitopes is supported by both self and allo-recognition.

Donor-specific antibody (DSA) responses against human leukocyte antigen (HLA) proteins mismatched between kidney transplant donors and recipients cause allograft loss. Using single-cell, molecular, structural, and proteomic techniques, we profiled the HLA-specific (alloreactive) B cell response in kidney and blood of a transplant recipient with antibody-mediated rejection (AMR). We identified 14 distinct alloreactive B cell lineages, which spanned the rejected organ and blood and expressed high-affinity anti-donor HLA-specific B cell receptors, many of which were clonally linked to circulating DSA. The alloreactive B cell response was focused on exposed, solvent-accessible mismatched HLA residues, while also demonstrating extensive contacts with self-HLA residues. Consistent with structural evidence of self-recognition, measurable self-reactivity by donor-specific B cells was common and positively correlated with anti-donor affinity maturation. Thus, allo- and self-reactive signatures appeared to converge, suggesting that during AMR, the recognition of non-self and breaches of tolerance conspire to produce a pathogenic donor-specific adaptive response.

A Qualitative Study to Inform Development of a Behavioral Intervention to Promote Food Allergy Self-Management and Adjustment among Early Adolescents.

Objective: Adolescence is a high-risk period for patients with food allergy (FA) as management responsibilities shift to the youth. This study used qualitative methods to explore FA experiences among a diverse pediatric FA population and inform behavioral intervention development. Methods: A total of 26 adolescents ages 9-14 years with IgE-mediated FA (M age = 11.92 years; 62% male; 42% Black, 31% White, 12% Hispanic/Latinx) and 25 primary caregivers (M age = 42.57 years; 32% annual income > $100,000) were recruited from FA clinics to complete separate qualitative interviews about FA-related experiences. Interviews were audio-recorded, transcribed, and entered into Dedoose, a qualitative software program. A grounded theory qualitative analytic approach was used to analyze data. Results: Emergent themes include: 1) FA is a chronic burden that affects daily life, 2) Families experience anxiety about FA, 3) Families find it challenging to transition FA management from parent to child, 4) FA families feel the need to be prepared, 5) FA families frequently advocate for their needs, and 6) Social experiences affect the FA experience. Conclusions: Adolescents with FA and their caregivers experience daily stress related to their chronic illness. A behavioral intervention that provides FA education, bolsters stress/anxiety management, assists parents in transitioning FA management responsibility to the youth, teaches executive functioning and advocacy skills, and fosters peer support could help adolescents successfully cope with and manage FA in their daily lives.

The Type 2 Diabetes Knowledge Portal: An open access genetic resource dedicated to type 2 diabetes and related traits.

Associations between human genetic variation and clinical phenotypes have become a foundation of biomedical research. Most repositories of these data seek to be disease-agnostic and therefore lack disease-focused views. The Type 2 Diabetes Knowledge Portal (T2DKP) is a public resource of genetic datasets and genomic annotations dedicated to type 2 diabetes (T2D) and related traits. Here, we seek to make the T2DKP more accessible to prospective users and more useful to existing users. First, we evaluate the T2DKP's comprehensiveness by comparing its datasets with those of other repositories. Second, we describe how researchers unfamiliar with human genetic data can begin using and correctly interpreting them via the T2DKP. Third, we describe how existing users can extend their current workflows to use the full suite of tools offered by the T2DKP. We finally discuss the lessons offered by the T2DKP toward the goal of democratizing access to complex disease genetic results.

Immune response evolution in peanut epicutaneous immunotherapy for peanut-allergic children.

BACKGROUND: Epicutaneous immunotherapy with investigational Viaskin™ Peanut 250 µg (DBV712) has demonstrated statistically superior desensitization versus placebo in peanut-allergic children in clinical trials. It is unclear whether serologic biomarkers predict response. METHODS: Serum-specific IgG4 and IgE (whole peanut and components) from subjects enrolled in the phase 3 Efficacy and Safety of Viaskin Peanut in Children With IgE-Mediated Peanut Allergy study were examined by exploratory univariate and multivariate analyses to determine trajectories and predictors of treatment response, based upon peanut protein eliciting dose (ED) at Month (M) 12 double-blind placebo-controlled food challenge. RESULTS: Among Viaskin Peanut-treated subjects, peanut sIgG4 significantly increased from baseline through M12 and peanut sIgE peaked at M3 and fell below baseline by M12, with sIgG4 and sIgE peanut components mirroring these trajectories. Placebo subjects had no significant changes. By univariate analysis, M12 peanut sIgG4/sIgE was higher in treatment responders (p < 0.001) and had highest area under the curve (AUC) for predicting ED ≥300 mg and ≥1000 mg (AUC 69.5% and 69.9%, respectively). M12 peanut sIgG4/sIgE >20.1 predicted M12 ED ≥300 mg (80% positive predictive value). The best performing component was Ara h 1 sIgE <15.7 kUA /L (AUC 66.5%). A multivariate model combining Ara h 1 and peanut sIgG4/sIgE had an AUC of 68.2% (ED ≥300 mg) and 67.8% (ED ≥1000 mg). CONCLUSIONS: Peanut sIgG4 rise most clearly differentiated Viaskin Peanut versus placebo subjects. sIgG4/sIgE ratios >20.1 and the combination of Ara h 1 and peanut sIgG4/sIgE had moderate ability to predict treatment response and could potentially be useful for clinical monitoring. Additional data are needed to confirm these relationships.

MDA5-dependent responses contribute to autoimmune diabetes progression and hindrance.

Type 1 diabetes (T1D) is an autoimmune disease resulting in pancreatic ß cell destruction. Coxsackievirus B3 (CVB3) infection and melanoma differentiation-associated protein 5-dependent (MDA5-dependent) antiviral responses are linked with T1D development. Mutations within IFIH1, coding for MDA5, are correlated with T1D susceptibility, but how these mutations contribute to T1D remains unclear. Utilizing nonobese diabetic (NOD) mice lacking Ifih1 expression (KO) or containing an in-frame deletion within the ATPase site of the helicase 1 domain of MDA5 (ΔHel1), we tested the hypothesis that partial or complete loss-of-function mutations in MDA5 would delay T1D by impairing proinflammatory pancreatic macrophage and T cell responses. Spontaneous T1D developed in female NOD and KO mice similarly, but was significantly delayed in ΔHel1 mice, which may be partly due to a concomitant increase in myeloid-derived suppressor cells. Interestingly, KO male mice had increased spontaneous T1D compared with NOD mice. Whereas NOD and KO mice developed CVB3-accelerated T1D, ΔHel1 mice were protected partly due to decreased type I IFNs, pancreatic infiltrating TNF+ macrophages, IFN-γ+CD4+ T cells, and perforin+CD8+ T cells. Furthermore, ΔHel1 MDA5 protein had reduced ATP hydrolysis compared with wild-type MDA5. Our results suggest that dampened MDA5 function delays T1D, yet loss of MDA5 promotes T1D.

Intraspecific variation and directional casque asymmetry in adult southern cassowaries (Casuarius casuarius).

The cranial casques of modern cassowaries (Casuarius) have long intrigued researchers; however, in-depth studies regarding their morphological variation are scarce. Through visual inspection, it has been recognized that casque variability exists between conspecifics. Understanding casque variation has both evolutionary and ecological importance. Although hypothesized to be targeted by selection, intraspecific casque variation has not been quantified previously. Through a large sample of C. casuarius (n = 103), we compared casque shape (lateral and rostral views) between sexes and between individuals from non-overlapping geographical regions using two-dimensional (2D) geometric morphometrics. We found no statistically significant differences between the casque shape of females and males and few substantial shape differences between individuals from different geographic areas. Much of the intraspecific variation within C. casuarius is due to casque asymmetries (77.5% rightward deviating, 20.7% leftward deviating, and 1.8% non-deviating from the midline; n = 111), which explain the high variability of southern cassowary casque shape, particularly from the rostral aspect. Finally, we discuss how our non-significant findings implicate social selection theory, and we identify the benefits of quantifying such variation for further elucidating casque function(s) and the social biology of cassowaries.

The Impact of Allergy Specialty Care on Health Care Utilization Among Peanut Allergy Children in the United States.

BACKGROUND: The influence of allergist management on peanut allergy (PA)-related health care utilization is unknown. OBJECTIVE: To determine whether allergist care lowers PA costs. METHODS: IBM MarketScan Commercial Claims and Encounters Database was analyzed for PA diagnosis/reaction-related codes (January 2010-June 2019) in patients 64 years or younger, with demographically matched non-PA food allergy controls (NPAFACs). Outcomes were measured and compared 12 months before/after first claim date. RESULTS: Among 72,854 persons with PA (39,068 with ≥1 allergist visit, 53.6%), and 166,825 NPAFACs, the number of National Drug Codes and International Classification of Diseases, 10th Revision codes was higher for persons with PA with versus without an allergist visit during both baseline and follow-up (all P < .001). Persons with PA with versus without an allergist visit were prescribed epinephrine at significantly higher rates (RR, 1.67; P < .001). Rates of epinephrine claims, mean epinephrine costs, and proportion with peanut anaphylaxis were higher among the PA group with versus without an allergist visit (69.9% vs 63.3%; $676 vs $493, 48.9% vs 20.7%; all P < .001). The proportion with anaphylaxis episodes was higher in the PA group versus the NPAFAC group (53.1% vs 31.6%; P < .001). Total health care costs were higher in the NPAFAC group versus the PA group ($7863 vs $7261; P < .001) and lower for persons with PA with versus without an allergist visit ($6347 vs $8270; P < .001), with no significant differences in PA reaction-related costs between PA groups. CONCLUSIONS: Higher rates of anaphylaxis were seen among the PA group with versus without an allergist visit during the follow-up period (53.6% of overall PA group). Allergist care was associated with a reduction in total health care costs and higher rates of epinephrine prescription.

Cytokines and Production of Aberrantly O-Glycosylated IgA1, the Main Autoantigen in IgA Nephropathy.

Immunoglobulin A (IgA) nephropathy is the most common primary glomerulonephritis worldwide, with no disease-specific treatment and up to 40% of patients progressing to kidney failure. IgA nephropathy (IgAN), characterized by IgA1-containing immunodeposits in the glomeruli, is considered to be an autoimmune disease in which the kidneys are injured as innocent bystanders. Glomerular immunodeposits are thought to originate from the circulating immune complexes that contain aberrantly O-glycosylated IgA1, the main autoantigen in IgAN, bound by IgG autoantibodies. A common clinical manifestation associated with IgAN includes synpharyngitic hematuria at disease onset or during disease activity. This observation suggests a connection of disease pathogenesis with an activated mucosal immune system of the upper-respiratory and/or gastrointestinal tract and IgA1 glycosylation. In fact, some cytokines can enhance production of aberrantly O-glycosylated IgA1. This process involves abnormal cytokine signaling in IgA1-producing cells from patients with IgAN. In this article, we present our view of pathogenesis of IgAN and review how some cytokines can contribute to the disease process by enhancing production of aberrantly glycosylated IgA1. We also review current clinical trials of IgAN based on cytokine-targeting therapeutic approaches.

Atomic view of the HIV-1 matrix lattice; implications on virus assembly and envelope incorporation.

During the late phase of HIV type 1 (HIV-1) infection cycle, the virally encoded Gag polyproteins are targeted to the inner leaflet of the plasma membrane (PM) for assembly, formation of immature particles, and virus release. Gag binding to the PM is mediated by interactions of the N-terminally myristoylated matrix (myrMA) domain with phosphatidylinositol 4,5-bisphosphate. Formation of a myrMA lattice on the PM is an obligatory step for the assembly of immature HIV-1 particles and envelope (Env) incorporation. Atomic details of the myrMA lattice and how it mediates Env incorporation are lacking. Herein, we present the X-ray structure of myrMA at 2.15 Å. The myrMA lattice is arranged as a hexamer of trimers with a central hole, thought to accommodate the C-terminal tail of Env to promote incorporation into virions. The trimer­trimer interactions in the lattice are mediated by the N-terminal loop of one myrMA molecule and α-helices I­II, as well as the 310 helix of a myrMA molecule from an adjacent trimer. We provide evidence that substitution of MA residues Leu13 and Leu31, previously shown to have adverse effects on Env incorporation, induced a conformational change in myrMA, which may destabilize the trimer­trimer interactions within the lattice. We also show that PI(4,5)P2 is capable of binding to alternating sites on MA, consistent with an MA­membrane binding mechanism during assembly of the immature particle and upon maturation. Altogether, these findings advance our understanding of a key mechanism in HIV-1 particle assembly.

Psychometric parameters of food allergy quality of life during an allergen immunotherapy trial.

BACKGROUND: The Food Allergy Quality of Life Questionnaire-Parent Form (FAQLQ-PF) is a commonly used patient-reported outcome measure in food allergy (FA) research. It was developed before FA treatment clinical trials were commonplace and is used as a secondary outcome measure in pivotal FA treatment trials. We examined the psychometric properties of the FAQLQ-PF and its relevance to children with peanut allergy engaged in an epicutaneous immunotherapy (EPIT) clinical trial. METHODS: Analysis was performed on 26 universally answered items of the FAQLQ-PF, from assessments undertaken during the phase 3 PEPITES study (baseline, Month 12), which examined the safety and efficacy of EPIT for children with peanut allergy aged 4-11 years. Item response theory (IRT) was used to assess psychometric parameters of the FAQLQ-PF (i.e., discrimination, difficulty, and information). Confirmatory factor analysis was also employed; reliability was assessed using McDonald's omega (ω) and Cronbach's alpha (α). RESULTS: A total of 23 of 26 items presented very high discrimination levels (>1.7), and all 26 fell within the recommended difficulty threshold (between -1.5 and 1.5). The items contributed a reasonable information level for their respective factors/subdomains. The measure also presented a marginally acceptable model fit for the 3-factor structure (e.g., comparative fit index = 0.88, Tucker-Lewis index = 0.87) and good reliability levels across time points (ω and α > 0.90). CONCLUSIONS: Herein, we present a novel reanalysis of the FAQLQ-PF items using IRT. The longitudinal performance of individual items and subscales was corroborated, and items with the highest discrimination were identified, showing that the tool is suitable for longitudinal measurements in FA treatment trials.