Impact of mAb-FcRn affinity on IgG transcytosis across human well-differentiated airway epithelium.

Effective treatment and immunoprophylaxis of viral respiratory infections with neutralizing monoclonal antibodies (mAbs) require maintaining inhibitory concentrations of mAbs at the airway surface. While engineered mAbs with increased affinity to the neonatal Fc receptor (FcRn) are increasingly employed, little is known how increased affinity of Fc to FcRn influences basal-to-apical transepithelial transport (transcytosis) of mAbs across the airway epithelium. To investigate this, we utilized a model of well-differentiated human airway epithelium (WD-HAE) that exhibited robust FcRn expression, and measured the transepithelial transport of a mAb against SARS-CoV-2 Spike protein (CR3022) with either wildtype IgG-Fc or Fc modified with YTE or LS mutations known to increase affinity for FcRn.

RSV infection of humanized lung-only mice induces pathological changes resembling severe bronchiolitis and bronchopneumonia.

Respiratory syncytial virus (RSV) is a substantial cause of severe lower respiratory tract infections in infants, young children, older adults, and immunocompromised individuals. There is a vital need for effective therapeutics to prevent and/or treat severe RSV infection in these high-risk individuals. The development and pre-clinical testing of candidate RSV therapeutics could be accelerated by their evaluation in animals models that recapitulate bronchiolitis and bronchopneumonia; both hallmark features of severe RSV infection of humans.

Prolonged airway explant culture enables study of health, disease, and viral pathogenesis.

In vitro models play a major role in studying airway physiology and disease. However, the native lung's complex tissue architecture and non-epithelial cell lineages are not preserved in these models. Ex vivo tissue models could overcome in vitro limitations, but methods for long-term maintenance of ex vivo tissue has not been established.

Inhaled "Muco-Trapping" Monoclonal Antibody Effectively Treats Established Respiratory Syncytial Virus (RSV) Infections.

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in infants, the immunocompromised, and the elderly. RSV infects the airway epithelium via the apical membrane and almost exclusively sheds progeny virions back into the airway mucus (AM), making RSV difficult to target by systemically administered therapies. An inhalable "muco-trapping" variant of motavizumab (Mota-MT), a potent neutralizing mAb against RSV F is engineered.

Viral airway injury promotes cell engraftment in an in vitro model of cystic fibrosis cell therapy.

Cell therapy is a potential treatment for cystic fibrosis (CF). However, cell engraftment into the airway epithelium is challenging. Here, we model cell engraftment in vitro using the air-liquid interface (ALI) culture system by injuring well-differentiated CF ALI cultures and delivering non-CF cells at the time of peak injury.

Human T cells efficiently control RSV infection.

Respiratory syncytial virus (RSV) infection causes significant morbidity and mortality in infants, immunocompromised individuals, and older individuals. There is an urgent need for effective antivirals and vaccines for high-risk individuals. We used 2 complementary in vivo models to analyze RSV-associated human lung pathology and human immune correlates of protection.

Thiol-based chemical probes exhibit antiviral activity against SARS-CoV-2 via allosteric disulfide disruption in the spike glycoprotein.

The development of small-molecules targeting different components of SARS-CoV-2 is a key strategy to complement antibody-based treatments and vaccination campaigns in managing the COVID-19 pandemic. Here, we show that two thiol-based chemical probes that act as reducing agents, P2119 and P2165, inhibit infection by human coronaviruses, including SARS-CoV-2, and decrease the binding of spike glycoprotein to its receptor, the angiotensin-converting enzyme 2 (ACE2). Proteomics and reactive cysteine profiling link the antiviral activity to the reduction of key disulfides, specifically by disruption of the Cys379-Cys432 and Cys391-Cys525 pairs distal to the receptor binding motif in the receptor binding domain (RBD) of the spike glycoprotein.

Pharmacokinetic-based failure of a detergent virucidal for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) nasal infections: A preclinical study and randomized controlled trial.

Background: The nose is the portal for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection, suggesting the nose as a target for topical antiviral therapies. The purpose of this study was to assess both the in vivo and in vitro efficacy of a detergent-based virucidal agent, Johnson and Johnson's Baby Shampoo (J&J), in SARS-CoV-2-infected subjects.

Methods: Subjects were randomized into three treatment groups: (1) twice daily nasal irrigation with J&J in hypertonic saline, (2) hypertonic saline alone, and (3) no intervention.

Pharmacokinetic-based failure of a detergent virucidal for SARS-COV-2 nasal infections.

The nose is the portal for SARS-CoV-2 infection, suggesting the nose as a target for topical antiviral therapies. Because detergents are virucidal, Johnson and Johnson's Baby Shampoo (J&J) was tested as a topical virucidal agent in SARS-CoV-2 infected subjects. Twice daily irrigation of J&J in hypertonic saline, hypertonic saline alone, or no intervention were compared (n = 24/group).

SARS-CoV-2 infection is effectively treated and prevented by EIDD-2801.

All coronaviruses known to have recently emerged as human pathogens probably originated in bats. Here we use a single experimental platform based on immunodeficient mice implanted with human lung tissue (hereafter, human lung-only mice (LoM)) to demonstrate the efficient in vivo replication of severe acute respiratory syndrome coronavirus (SARS-CoV), Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), as well as two endogenous SARS-like bat coronaviruses that show potential for emergence as human pathogens. Virus replication in this model occurs in bona fide human lung tissue and does not require any type of adaptation of the virus or the host.

Learning from past failures: Challenges with monoclonal antibody therapies for COVID-19.

COVID-19, the disease caused by infection with SARS-CoV-2, requires urgent development of therapeutic interventions. Due to their safety, specificity, and potential for rapid advancement into the clinic, monoclonal antibodies (mAbs) represent a highly promising class of antiviral or anti-inflammatory agents. Herein, by analyzing prior efforts to advance antiviral mAbs for other acute respiratory infections (ARIs), we highlight the challenges faced by mAb-based immunotherapies for COVID-19.

Precision mouse models with expanded tropism for human pathogens.

A major limitation of current humanized mouse models is that they primarily enable the analysis of human-specific pathogens that infect hematopoietic cells. However, most human pathogens target other cell types, including epithelial, endothelial and mesenchymal cells. Here, we show that implantation of human lung tissue, which contains up to 40 cell types, including nonhematopoietic cells, into immunodeficient mice (lung-only mice) resulted in the development of a highly vascularized lung implant.

A live RSV vaccine with engineered thermostability is immunogenic in cotton rats despite high attenuation.

Respiratory syncytial virus (RSV) is a leading cause of infant hospitalization and there remains no pediatric vaccine. RSV live-attenuated vaccines (LAVs) have a history of safe testing in infants; however, achieving an effective balance of attenuation and immunogenicity has proven challenging. Here we seek to engineer an RSV LAV with enhanced immunogenicity.

SARS-like WIV1-CoV poised for human emergence.

Outbreaks from zoonotic sources represent a threat to both human disease as well as the global economy. Despite a wealth of metagenomics studies, methods to leverage these datasets to identify future threats are underdeveloped. In this study, we describe an approach that combines existing metagenomics data with reverse genetics to engineer reagents to evaluate emergence and pathogenic potential of circulating zoonotic viruses.

Respiratory syncytial virus (RSV) and its propensity for causing bronchiolitis.

Infants and young children with acute onset of wheezing and reduced respiratory airflows are often diagnosed with obstruction and inflammation of the small bronchiolar airways, ie bronchiolitis. The most common aetological agents causing bronchiolitis in young children are the respiratory viruses, and of the commonly encountered respiratory viruses, respiratory syncytial virus (RSV) has a propensity for causing bronchiolitis. Indeed, RSV bronchiolitis remains the major reason why previously healthy infants are admitted to hospital.

RSV-encoded NS2 promotes epithelial cell shedding and distal airway obstruction.

Respiratory syncytial virus (RSV) infection is the major cause of bronchiolitis in young children. The factors that contribute to the increased propensity of RSV-induced distal airway disease compared with other commonly encountered respiratory viruses remain unclear. Here, we identified the RSV-encoded nonstructural 2 (NS2) protein as a viral genetic determinant for initiating RSV-induced distal airway obstruction.

Effects of vitamin D on airway epithelial cell morphology and rhinovirus replication.

Vitamin D has been linked to reduced risk of viral respiratory illness. We hypothesized that vitamin D could directly reduce rhinovirus (RV) replication in airway epithelium. Primary human bronchial epithelial cells (hBEC) were treated with vitamin D, and RV replication and gene expression were evaluated by quantitative PCR.

Human airway epithelial cell cultures for modeling respiratory syncytial virus infection.

Respiratory syncytial virus (RSV) is an important human respiratory pathogen with narrow species tropism. Limited availability of human pathologic specimens during early RSV-induced lung disease and ethical restrictions for RSV challenge studies in the lower airways of human volunteers has slowed our understanding of how RSV causes airway disease and greatly limited the development of therapeutic strategies for reducing RSV disease burden. Our current knowledge of RSV infection and pathology is largely based on in vitro studies using nonpolarized epithelial cell-lines grown on plastic or in vivo studies using animal models semipermissive for RSV infection.

Overexpressing mouse model demonstrates the protective role of Muc5ac in the lungs.

MUC5AC, a major gel-forming mucin expressed in the lungs, is secreted at increased rates in response to infectious agents, implying that mucins exert a protective role against inhaled pathogens. However, epidemiological and pathological studies suggest that excessive mucin secretion causes airways obstruction and inflammation. To determine whether increased MUC5AC secretion alone produces airway obstruction and/or inflammation, we generated a mouse model overexpressing Muc5ac mRNA ~20-fold in the lungs, using the rCCSP promoter.

Human parainfluenza virus serotypes differ in their kinetics of replication and cytokine secretion in human tracheobronchial airway epithelium.

Human parainfluenza viruses (PIVs) cause acute respiratory illness in children, the elderly, and immunocompromised patients. PIV3 is a common cause of bronchiolitis and pneumonia, whereas PIV1 and 2 are frequent causes of upper respiratory tract illness and croup. To assess how PIV1, 2, and 3 differ with regard to replication and induction of type I interferons, interleukin-6, and relevant chemokines, we infected primary human airway epithelium (HAE) cultures from the same tissue donors and examined replication kinetics and cytokine secretion.

Comparison of differing cytopathic effects in human airway epithelium of parainfluenza virus 5 (W3A), parainfluenza virus type 3, and respiratory syncytial virus.

Parainfluenza virus 5 (PIV5) infects a wide range of animals including dogs, pigs, cats, and humans; however, its association with disease in humans remains controversial. In contrast to parainfluenza virus 3 (PIV3) or respiratory syncytial virus (RSV), PIV5 is remarkably non-cytopathic in monolayer cultures of immortalized epithelial cells. To compare the cytopathology produced by these viruses in a relevant human tissue, we infected an in vitro model of human ciliated airway epithelium and measured outcomes of cytopathology.

Limited effects of Muc1 deficiency on mouse adenovirus type 1 respiratory infection.

Muc1 (MUC1 in humans) is a membrane-tethered mucin that exerts anti-inflammatory effects in the lung during bacterial infection. Muc1 and other mucins are also likely to form a protective barrier in the lung. We used mouse adenovirus type 1 (MAV-1, also known as MAdV-1) to determine the role of Muc1 in the pathogenesis of an adenovirus in its natural host.

AAV-6 mediated efficient transduction of mouse lower airways.

AAV1 and AAV6 are two closely related AAV serotypes. In the present study, we found AAV6 was more efficient in transducing mouse lower airway epithelia in vitro and in vivo than AAV1. To further explore the mechanism of this difference, we found that significantly more AAV1 bound to mouse airway epithelia than AAV6, yet transduction by AAV6 was far superior.

NLRX1 protein attenuates inflammatory responses to infection by interfering with the RIG-I-MAVS and TRAF6-NF-κB signaling pathways.

The nucleotide-binding domain and leucine-rich-repeat-containing (NLR) proteins regulate innate immunity. Although the positive regulatory impact of NLRs is clear, their inhibitory roles are not well defined. We showed that Nlrx1(-/-) mice exhibited increased expression of antiviral signaling molecules IFN-β, STAT2, OAS1, and IL-6 after influenza virus infection.