Monoclonal Antibody Research Articles

ACBP/DBI neutralization for the experimental treatment of fatty liver disease.

Acyl-CoA binding protein (ACBP), also known as diazepam-binding inhibitor (DBI), is an extracellular checkpoint of autophagy. Here, we report that patients with histologically confirmed metabolic-associated steatohepatitis (MASH) or liver fibrosis exhibit elevated levels of circulating ACBP/DBI protein as compared to non-affected controls. Plasma ACBP/DBI strongly correlated with the NAFLD and FIB4 scores in patients, and these correlations were independent of age and body mass index. We studied the capacity of a monoclonal antibody (mAb) neutralizing mouse ACBP/DBI to combat active liver disease in several mouse models, in which steatohepatitis had been induced by four different protocols, namely, (i) methionine/choline-deficient diet, (ii) Western style diet (WD) alone, (iii) WD combined with the hepatotoxic agent CCl4, and (iv) a combination of CCl4 injections and oral ethanol challenge. Injections of anti-ACBP/DBI mAb attenuated histological, enzymological, metabolomic and transcriptomic signs of liver damage in these four models, hence halting or reducing the progression of non-alcoholic and alcoholic liver disease. Steatosis, inflammation, ballooning and fibrosis responded to ACBP/DBI inhibition at the preclinical level. Altogether, these findings support a causal role of ACBP/DBI in MASH and liver fibrosis, as well as the possibility to therapeutically target ACBP/DBI.

Site-Specific Quadruple-Functionalised Antibodies.

Antibody-drug conjugates (ADCs) are a growing class of chemotherapeutic agents that have yielded striking clinical successes. However, the efficacy of ADCs often suffers from issues associated with tumor heterogeneity and resistance. To overcome these problems, a new generation of ADCs comprising a single monoclonal antibody with multiple different payloads attached, termed multi-payload ADCs, have been developed. Here we deploy multiple orthogonal site-specific protein modification strategies to generate highly homogeneous multi-functionalised antibody conjugates comprising up to four different functionalities installed at four unique sites on the antibody. This work, which includes the use of a site-specific cyclopropenone (CPO)-based reagent, represents the first example of a homogeneous multi-payload ADC with a payload count greater than two, and thereby facilitates the development of the next generation of ADCs.

Site‐Specific Quadruple‐Functionalised Antibodies

AbstractAntibody–drug conjugates (ADCs) are a growing class of chemotherapeutic agents that have yielded striking clinical successes. However, the efficacy of ADCs often suffers from issues associated with tumor heterogeneity and resistance. To overcome these problems, a new generation of ADCs comprising a single monoclonal antibody with multiple different payloads attached, termed multi‐payload ADCs, have been developed. Here we deploy multiple orthogonal site‐specific protein modification strategies to generate highly homogeneous multi‐functionalised antibody conjugates comprising up to four different functionalities installed at four unique sites on the antibody. This work, which includes the use of a site‐specific cyclopropenone (CPO)‐based reagent, represents the first example of a homogeneous multi‐payload ADC with a payload count greater than two, and thereby facilitates the development of the next generation of ADCs.

A humanized neutralizing antibody protects against human adenovirus type 7 infection in humanized desmoglein-2 and CD46 double-receptor transgenic mice.

Human adenovirus type 7 (HAdV7) has become a major public health threat due to its widespread transmission, severe associated pneumonia, and a lack of effective anti-HAdV7 drugs. The aim of the current study is to design a humanized monoclonal antibody (mAb) demonstrating efficacy against HAdV-7 infections in vitro and in vivo. The humanized neutralizing antibody, 3G5-hu, was derived from the murine mAb 3G5. Antibody activity was evaluated using a flow cytometry-based neutralization (FCN) assay to identify humanized mAbs retaining potent neutralizing activity. Additionally, a humanized hDSG2/hCD46 dual-receptor transgenic mouse model was developed to simulate HAdV-7 infection. Using recombinant HAdV-7 expressing enhanced green fluorescent protein and clinically isolated wild-type HAdV-7, the half-maximal effective concentration of 3G5-hu against HAdV-7 was determined to be < 30 ng/mL. Notably, 3G5-hu exhibits high specificity for the hexon protein of the HAdV-7 capsid (affinity: KD = 9.02 × 10- 11 M). Microneutralization studies with wild-type HAdV-7 and rAd7EGFP confirmed that humanized mAb 3G5-hu neutralizes 10-30 ng/mL HAdV-7 (approximately 67-200 pM). Furthermore, hDSG2/hCD46 double-receptor transgenic mice are more susceptible to HAdV-7 infection than single-receptor transgenic mice. Meanwhile, the humanized mAb 3G5-hu provides good protection against HAdV-7 infection in hDSG2/hCD46 knock-in transgenic mice. The newly designed humanized mAb 3G5-hu specifically neutralizes HAdV-7 in vitro and in vivo. 3G5-hu elicits protection against HAdV-7 infection in hDSG2/hCD46 knock-in transgenic mice. The findings of this study provide insights to guide the future development of preventative and therapeutic treatments for HAdV-7 infection.

Side-by-Side Economic Process Model for the Comparison and Evaluation of Magnetic Bead-Based Processes and Legacy Process for the Manufacturing of Monoclonal Antibodies

This study models two alternative downstream processes based on magnetic separation with the objective of understanding the economic feasibility of these processes compared to the traditional mAb process. The key focus lies in the economic understanding of the cell harvest and capture steps in the models. Here, the models revealed that integrating cell removal and product capture in a single operation is the main factor driving the unified productivity between USP and the magnetic bead-based processes. This results in significant economic benefits, such as savings in both the cost of goods per gram of mAb and fixed costs, as well as increasing annual facility output. The predicted savings potential approaches 38% for COGs, 17% for capital investment, and 40% for annual facility output. For mammalian cell-based manufacturing, the magnetic separation-based DSP provides a highly valuable option due to its integration of several individual unit operations compared to the traditional process both in reducing process time and cost and accommodating higher demands.

Identification and Characterization of Linear Epitopes of Monoclonal Antibodies Against African Horse Sickness Virus Serotype 1 VP2 Protein

African horse sickness (AHS) is an acute, fatal, contagious disease of animals of the family Equidae and is caused by infection with the African horse sickness virus (AHSV). Based on the outer capsid protein VP2, AHSV is classified into nine serotypes (AHSV−1 to −9) with little or no serological cross-reactivity between them. In 2020, AHS outbreaks caused by AHSV−1 were reported in Thailand and Malaysia, marking the first occurrences of AHS in Southeast Asia. However, little is known about the antigenic profile of AHSV−1 VP2. In this study, a recombinant VP2 protein was expressed in Escherichia coli and used as an immunogen, and three monoclonal antibodies (mAbs), designated 7D11, 10A9, and 9E7, against AHSV−1 VP2, were generated. These three mAbs were then successfully used in IFA, WB, and ELISA for the detection of AHSV−1 VP2. Two overlapping linear epitopes, 670NEFDFE675 (E670–675) recognized by 9E7 and 670NEFDF674 (E670–674) recognized by 7D11 and 10A9, were identified through truncation of GST-fused VP2. Amino acid sequence alignment shows that the 670NEFDFE675 motif is completely conserved within AHSV−1 but is highly divergent in other AHSV serotypes. Our studies provide an important tool for basic research into AHSV−1 and for the diagnosis of AHSV−1.

Downhill running does not alter blood C1q availability or complement-dependent cytotoxicity of therapeutic monoclonal antibodies against haematological cancer cell lines in vitro.

Complement-dependent cytotoxicity (CDC) is a primary mechanism-of-action of monoclonal antibody (mAb) immunotherapies used to treat haematological cancers, including rituximab and daratumumab. However, mAb efficacy may be limited by reduced bioavailability of complement C1q - which activates the complement classical pathway following interactions with mAb-opsonised target cells. C1q is secreted by phagocytes upon recruitment to sites of muscle damage to facilitate muscular repair, hence we hypothesised that muscle damaging exercise may increase C1q 'spill-over' into blood. Additionally, other complement proteins (e.g., C1s) have been reported to increase following ultra-endurance and resistance exercise. Taken together, we hypothesised that muscle damaging exercise could be harnessed to enhance mAb-mediated CDC. In this study, n = 8 healthy males (28 ± 5-years) completed two 45-minute treadmill running protocols: (1) a flat running protocol at a speed 15% above anaerobic threshold, and (2) a downhill running protocol (- 10% slope) at the same speed. Blood samples were collected before, immediately after, and 1-hour, 24-hours, 2-days, and 4-days after exercise. Isolated serum was assessed for C1q by ELISA, and used to measure mAb (rituximab, daratumumab) mediated CDC against two haematological cancer cell lines (Raji, RPMI-8226) in vitro. Isolated plasma was assessed for markers of inflammation (C-reactive protein [CRP]), and muscle damage (creatine kinase [CK]) by turbidimetry. C1q and CDC activity were not different between running protocols and did not change over time (p > 0.05). Significantly greater perceived muscle soreness (p < 0.001) and fluctuations observed from baseline to 24-hours post-exercise in the downhill running trial in CK (+ 171%) and CRP (+ 66%) suggests some degree of muscle damage was present. It is possible that any increase in C1q post-exercise may have been masked by the increase and subsequent interaction with CRP, which utilises C1q to facilitate muscular repair. This is the first study to investigate whether exercise can increase circulating C1q and improve mAb-mediated CDC and our findings show that downhill running exercise does not increase circulating C1q nor improve CDC in vitro.

Age differences in the treatment of lung cancer-a cohort study among 42,000 patients from Germany.

We aimed to describe treatment of lung cancer patients in Germany based on health claims data, focusing particularly on differences by age. Using the German Pharmacoepidemiological Research Database (GePaRD, ~ 20% of the German population) we identified lung cancer patients diagnosed in 2015-2018 based on a previously developed algorithm and followed them until death, end of continuous insurance or end of 2020. We described initial treatment patterns after diagnosis and survival, stratified among others by age. We included 42,629 incident lung cancer patients (58% male). Surgery within three months after diagnosis was performed in 36%, 31%, 29% and 18% of patients aged < 50, 50-69, 70-79 and ≥ 80, respectively. Among patients without surgery, systemic therapy was administered in 77%, 72%, 54% and 25% of patients aged < 50, 50-69, 70-79 and ≥ 80, respectively. Monoclonal antibodies were administered in 15-30% of patients across age groups, and 4% to 15% received protein kinase inhibitors. Overall, 21% of patients remained untreated. In the age groups < 50, 50-69, 70-79 and ≥ 80, this proportions was 9%, 12%, 22% and 48%, respectively. In conclusion, our study provides a comprehensive overview of the therapy of lung cancer patients in Germany and quantitatively demonstrates the considerable differences between age groups. In terms of clinical cancer registration, the results are useful to estimate the completeness of data for the different types of treatment.

Protective threshold of a potent neutralizing Zika virus monoclonal antibody in rhesus macaques.

Zika virus (ZIKV) is a mosquito-borne flavivirus that caused a global pandemic in 2016-2017 with continued ongoing transmission at low levels in several countries. In the absence of an approved ZIKV vaccine, neutralizing monoclonal antibodies (mAbs) provide an option for the prevention and treatment of ZIKV infection. Previous studies identified a potent neutralizing human mAb ZIKV-117 that reduced fetal infection and death in mice following ZIKV challenge. In this study, we report exquisite potency of ZIKV-117-LALA-YTE, which has been engineered to reduce Fc receptor binding and to extend half-life, in a titration study in rhesus macaques to protect against ZIKV challenge. We show complete protection at a dose of 0.016 mg/kg ZIKV-117-LALA-YTE, which resulted in median serum concentrations of 0.13 µg/mL. The high potency of this mAb supports its potential clinical development as a novel biotherapeutic intervention for ZIKV.IMPORTANCEIn this study, we report the potency of the Zika virus (ZIKV)-specific neutralizing antibody ZIKV-117-LALA-YTE against ZIKV challenge in a titration study rhesus macaques. This high potency supports the further development of this monoclonal antibody for ZIKV.

Exploring Risk Factors Associated With Intensive Care Unit Admission in a Retrospective Cohort of 631 Children With Bronchiolitis.

Examine the trends and epidemiological features of acute hospitalized bronchiolitis cases among children aged 28 days to 2 years, both before and after the COVID-19 pandemic. Furthermore, evaluate their need for intensive care unit (ICU) admission and identify primary risk factors associated with severe bronchiolitis. A retrospective analysis was conducted on the medical records of paediatric patients admitted to Meyer Children's Hospital in Florence (Italy) from September 2019 to March 2023, with the diagnosis of bronchiolitis. Between 2019 and 2023, bronchiolitis hospitalizations grew by 76%, going from 131 to 230 cases, after the historical minimum of 14 cases in the 2020-2021 season. Respiratory syncytial virus (RSV) infection emerged as the predominant etiological agent, contributing to 76% of hospitalizations in both 2021-2022 and 2022-2023 seasons. Coinfection cases increased fivefold from 2019 to 2023, accounting for 23% of hospitalizations in 2022-2023. In addition, the ICU admission rate increased from 13% in 2019-2020 to 31% of bronchiolitis hospitalizations in 2022-2023. Univariate and multivariate analysis data show that infants below 2 months of age, preterm births, comorbidities and RSV infections were correlated with a higher risk for ICU admission. The growing trend in ICU admissions for acute bronchiolitis in hospitalized children represents a substantial health challenge. Addressing the bronchiolitis epidemic necessitates a strategic focus on RSV prevention through interventions such as vaccines and monoclonal antibodies. Urgent implementation of preventive initiatives, together with continuous surveillance and the establishment of national databases, is imperative and cannot be further deferred.

Linking Effector Function to Antitumor Monoclonal Antibody Efficacy

Abstract This Pillars of Immunology article is a commentary on “Inhibitory Fc receptors modulate in vivo cytoxicity against tumor targets”, a pivotal article written by R. A. Clynes, T. L. Towers, L. G. Presta, and J. V. Ravetch, and published in Nature Medicine, in 2000. https://www.nature.com/articles/nm0400_443.

A new paradigm for optimized experimental design in cIEF platforms aimed at an accurate robust and reliable mAbs charge-variant assessment.

The success of therapeutic monoclonal antibodies (mAbs) and their biosimilars, highlights the challenge to control their purity, identity, and stability. For this purpose, among several orthogonal methodologies, imaged capillary Iso Electric Focusing (icIEF) is one of the leading techniques. Despite the isoelectric point (pI) being a univocal parameter relying on the protein's primary sequence and its post-translational modifications (PTMs), the current Charge Variants Profile Assessment (CVPA) carried out by cIEF relies on relative comparisons with corresponding reference standards, this is because the inconsistent outputs for the same sample across different instruments preclude the uniqueness of the measured parameters. We demonstrate that refining the current calibration approach in the iciEF method allows for obtaining more reliable and objective pIs, and a deeper understanding of the pH gradients along the capillaries. We are confident our advancements will enhance CVPA, by exploring the concept of univocal charge identity. This is crucial for constructing biobanks and developing algorithms to quickly identify divergences from the originators, thus ensuring drug quality, efficacy, and safety. Moreover, our method allows an experimental design optimized to minimize bias ("Unbiased" Experimental Design-UED) to study resolution as a multivariate function of different input variables. This endeavor aims to develop optimal methods tailored to specific pH ranges.

Single cell RNA-sequencing of feline peripheral immune cells with V(D)J repertoire and cross species analysis of T lymphocytes

IntroductionThe domestic cat (Felis catus) is a valued companion animal and a model for virally induced cancers and immunodeficiencies. However, species-specific limitations such as a scarcity of immune cell markers constrain our ability to resolve immune cell subsets at sufficient detail. The goal of this study was to characterize circulating feline T cells and other leukocytes based on their transcriptomic landscape and T-cell receptor repertoire using single cell RNA-sequencing.MethodsPeripheral blood from 4 healthy cats was enriched for T cells by flow cytometry cell sorting using a mouse anti-feline CD5 monoclonal antibody. Libraries for whole transcriptome, αβ T cell receptor transcripts and γδ T cell receptor transcripts were constructed using the 10x Genomics Chromium Next GEM Single Cell 5’ reagent kit and the Chromium Single Cell V(D)J Enrichment Kit with custom reverse primers for the feline orthologs.ResultsUnsupervised clustering of whole transcriptome data revealed 7 major cell populations - T cells, neutrophils, monocytic cells, B cells, plasmacytoid dendritic cells, mast cells and platelets. Sub cluster analysis of T cells resolved naive (CD4+ and CD8+), CD4+ effector T cells, CD8+ cytotoxic T cells and γδ T cells. Cross species analysis revealed a high conservation of T cell subsets along an effector gradient with equitable representation of veterinary species (horse, dog, pig) and humans with the cat. Our V(D)J repertoire analysis identified a subset of CD8+ cytotoxic T cells with skewed TRA and TRB gene usage, conserved TRA and TRB junctional motifs, restricted TRA/TRB pairing and reduced diversity in TRG junctional length. We also identified a public γδ T cell subset with invariant TRD and TRG chains and a CD4+ TEM-like phenotype. Among monocytic cells, we resolved three clusters of classical monocytes with polarization into pro- and anti-inflammatory phenotypes in addition to a cluster of conventional dendritic cells. Lastly, our neutrophil sub clustering revealed a larger mature neutrophil cluster and a smaller exhausted/activated cluster.DiscussionOur study is the first to characterize subsets of circulating T cells utilizing an integrative approach of single cell RNA-sequencing, V(D)J repertoire analysis and cross species analysis. In addition, we characterize the transcriptome of several myeloid cell subsets and demonstrate immune cell relatedness across different species.

Prospects of anti-GD2 immunotherapy for retinoblastoma

Retinoblastoma is the most common type of eye tumor in infants and children. Current treatments for retinoblastoma include intravenous chemotherapy, intra-arterial chemotherapy, intravitreal chemotherapy, cryotherapy, radiotherapy, and surgery. However, these treatments come accompanied by adverse effects such as the toxic side effects of chemotherapeutic drugs, post-operative complications including blindness after surgery, or other complications caused by radiotherapy. Immunotherapy is more promising for its low toxicity on normal cells and effectively improves the quality of life of patients. Disialoganglioside (GD2), a sphingolipid expressed on the surface of retinoblastoma, is a potential therapeutic target for retinoblastoma. We summarized immunotherapeutic approaches for both preclinical studies and clinical trials of GD2. An anti-GD2 monoclonal antibody (Dinutuximab), which has been approved for the treatment of high-risk neuroblastomas, has shown promising efficacy in improving patients’ prognosis. Additionally, chimeric antigen receptors (CAR)-T therapy, GD2 vaccines and nanoparticles are also potential therapeutics. Finally, we discuss the prospects and current limitations of these immunotherapeutic approaches for treating retinoblastoma, as well as how to address these problems.

Adaptation of Aglycosylated Monoclonal Antibodies for Improved Production in Komagataella phaffii.

Monoclonal antibodies (mAbs) are a major class of biopharmaceuticals manufactured by well-established processes using Chinese Hamster Ovary (CHO) cells. Next-generation biomanufacturing using alternative hosts like Komagataella phaffii could improve the accessibility of these medicines, address broad societal goals for sustainability, and offer financial advantages for accelerated development of new products. Antibodies produced by K. phaffii, however, may manifest unique molecular quality attributes, like host-dependent, product-related variants, that could raise potential concerns for clinical use. We demonstrate here conservative modifications to the amino acid sequence of aglycosylated antibodies based on the human IgG1 isotype that minimize product-related variations when secreted by K. phaffii. A combination of 2-3 changes of amino acids reduced variations across six different aglycosylated versions of commercial mAbs. Expression of a modified sequence of NIST mAb in both K. phaffii and CHO cells showed comparable biophysical properties and molecular variations. These results suggest a path toward the production of high-quality mAbs that could be expressed interchangeably by either yeast or mammalian cells. Improving molecular designs of proteins to enable a range of manufacturing strategies for well-characterized biopharmaceuticals could accelerate global accessibility and innovations.

A Novel Concept for Cleavable Linkers Applicable to Conjugation Chemistry - Design, Synthesis and Characterization.

Linkers with disulfide bonds are the only cleavable linkers that utilize physiological thiol gradients as a trigger to initiate the intracellular drug release cascade. Herein, we present a novel concept exploiting the thiol gradient phenomena to design a new class of cleavable linker with no disulfide bond. To support the concept, an electron-deficient sulfonamide-based cleavable linker amenable to conjugation of drug molecules with targeting agents, was developed. Modulating the electron-withdrawing nature of the aryl sulfonamide was critical to the balance between the stability and drug release. Favorable stability and payload release in human serum under physiologically relevant thiol concentrations was demonstrated with two potent cytotoxics. Intracellular payload release was further validated in cell-based assay in context of antibody-drug conjugate generated from monoclonal antibody and sulfonamide containing linker. To support the proposed release mechanism, possible downstream by-products formed from the drug-linker adduct were characterized.

Clinicopathologic feature and treatment progress of high-grade ovarian neuroendocrine tumors.

High-grade Ovarian neuroendocrine tumors represent a rare subset of ovarian neoplasms characterized by aggressive behavior, poor prognosis, and early metastasis. Despite their clinical significance, the management of these tumors lacks consensus due to their low incidence. This comprehensive review encompasses literature spanning from 1991 to 2024, focusing on the clinical presentation, diagnostic criteria, differential diagnosis, prognostic indicators, treatment modalities, and recent advancements in the understanding of this condition. Notably, a substantial proportion of affected individuals present during the perimenopausal period with unilateral lesions displaying mixed histological components. Biomarkers such as CA125, CA199, and NSE hold promise for aiding in the diagnosis and screening of ovarian neuroendocrine tumors. Unfortunately, patients exhibit a dismal prognosis even diagnosed at an early stage. Primary treatment strategies predominantly involve surgical intervention coupled with etoposide-cisplatin combination chemotherapy. In cases of recurrence, second-line chemotherapeutic agents including paclitaxel, irinotecan, and doxorubicin are commonly employed alongside localized radiotherapy. While specific genetic mutations remain elusive, emerging evidence suggests potential therapeutic effect involving mTOR inhibitors, PD-1 monoclonal antibodies, and antiangiogenic agents based on isolated case reports. The exploration of representative set of mutations will help for precise targeted therapies and remains a focal point of our ongoing research efforts.

Near-infrared fluorescent molecular probes with cetuximab in the in vivo fluorescence imaging for epithelial ovarian cancer.

Near-infrared fluorescence (NIRF) imaging is an excellent choice for image-guided surgery due to its simple operation and non-invasiveness. Developing tumor-specific fluorescent molecular probes is key to fluorescence imaging-guided surgery. EGFR (epidermal growth factor receptor) is closely related to the proliferation and growth of tumor cells and is highly expressed in epithelial ovarian cancer (EOC). The study aims to construct a NIR fluorescent molecular probe using cetuximab (an EGFR monoclonal antibody) and investigate its feasibility for targeting EOC in vivo through fluorescence imaging. We determined the expression of EGFR in EOC. NIR fluorescent molecular probe with cetuximab (cetuximab-Cy7) was chemically engineered and identified. The subcutaneous xenografted tumor model of EOC was induced using SKOV3-Luc cell line with positive expression of EGFR. Cetuximab-Cy7 was used for in vivo fluorescence imaging, and phosphate-buffered saline, free Cy7 dye and mouse isotype immunoglobulin G-Cy7 were used as controls. NIRF imaging system was performed to study the distribution and targeting of the probes. Tumors were imaged in situ and ex vivo, and fluorescent intensity was quantified. Resected specimens were analyzed to confirm diagnosis, and immunohistochemical (IHC) staining was used to identify EGFR expression. EGFR expression was increased in EOC tissues than fallopian tube tissues. The high expression of EGFR was significantly correlated with well-differentiation, residual lesions ≤ 1cm, no recurrence and increased survival. NIRF imaging showed that the cetuximab-Cy7 enabled detection of tumor lesions in EOC-bearing mice with the optimal dose of 30µg. The suitable imaging time window may be 24-96h post-injection. Ex vivo fluorescence imaging indicated that fluorescent signal was mainly detected in the tumor and the lung. IHC results confirmed that xenografts were EGFR positive. Cetuximab-Cy7 can specifically target the tumors of EOC xenografted nude mice. This research lays the foundation for future studies on EOC surgery navigation.

Echinochrome A inhibits HMGB1-induced vascular smooth muscle cell migration by suppressing osteopontin expression.

Echinochrome A (Ech A) isolated from marine organisms is a therapeutic effector for various cardiovascular diseases, but its precise mechanisms are unclear. This study identified the role and mechanisms mediating the effects of Ech A on the migration of vascular smooth muscle cells (VSMCs) induced by high-mobility group box 1 (HMGB1). Compared to the control cells, the migration of VSMCs stimulated with HMGB1 (100 ng/ml) was markedly increased, which was significantly attenuated in cells pretreated with MPIIIB10 (100 ng/ml), a neutralizing monoclonal antibody for osteopontin (OPN). In VSMCs stimulated with HMGB1, the increased expression of OPN mRNA and protein was accompanied by an increased OPN promoter activity. In reporter gene assays using OPN promoter-luciferase constructs, the promoter region 538-234 bp of the transcription start site containing the binding sites for activator protein 1 (AP-1) was shown to be responsible for the increased transcriptional activity by HMGB1. In addition, the binding activity of AP-1 was increased in HMGB1-stimulated cells, highlighting the pivotal role of AP-1 on OPN expression in HMGB1-stimulated VSMCs. An examination of the vascular effects of Ech A showed that the increased AP-1 binding/promoter activities and OPN expression induced by HMGB1 were attenuated in cells pretreated with Ech A (3 or 10 μM). Similarly, Ech A inhibited HMGB1-induced VSMC migration in a concentration-dependent manner. These findings suggest that Ech A inhibits VSMC migration by suppressing OPN expression. Hence, Ech A is suggested as a potential therapeutic strategy for vascular remodeling in the injured vasculatures.

Nirsevimab Effectiveness Against Medically Attended Respiratory Syncytial Virus Illness and Hospitalization Among Alaska Native Children - Yukon-Kuskokwim Delta Region, Alaska, October 2023-June 2024.

Respiratory syncytial virus (RSV) is a leading cause of hospitalization among young children. Historically, American Indian and Alaska Native (AI/AN) children have experienced high rates of RSV-associated hospitalization. In August 2023, a preventive monoclonal antibody (nirsevimab) was recommended for all infants aged <8 months (born during or entering their first RSV season) and for children aged 8-19 months (entering their second RSV season) who have increased risk for severe RSV illness, including all AI/AN children. This evaluation in Alaska's Yukon-Kuskokwim Delta region estimated nirsevimab effectiveness among AI/AN children in their first or second RSV seasons during 2023-2024. Among 472 children with medically attended acute respiratory illness (ARI), 48% overall had received nirsevimab ≥7 days earlier (median=91 days before the ARI-related visit). For children in their first RSV season (292), nirsevimab effectiveness was 76% (95% CI = 42%-90%) against medically attended RSV illness and 89% (95% CI = 32%-98%) against RSV hospitalization. For children in their second RSV season (180), effectiveness against medically attended RSV illness was 88% (95% CI=48%-97%). Nirsevimab is effective for preventing severe RSV illness among infants entering their first RSV season and children entering their second season with increased risk for severe RSV, including all AI/AN children.