Biology subjects

MacLoughlin, R.

Publications and source records attributed to MacLoughlin, R..

6 recordsLinked to original sources

bioRxiv2025

Local tolerance and innate immune activation of primary human respiratory cells exposed to flagellin

Antibiotic-resistant respiratory infections can lead to treatment failure, highlighting the need for alternative strategies. FLAMOD, a recombinant flagellin, stimulates innate immunity via Toll-like receptor 5 when delivered intranasally. In mice, FLAMOD protects against bacterial pneumonia. The protection is associated with activation of airway epithelial cells. This study aimed to assess the tolerance of human primary respiratory epithelium to FLAMOD administered apically as liquid droplets or by nebulization, to measure the innate immune response, and the pharmacokinetics of FLAMOD. We used epithelia reconstituted from human nasal and bronchial (MucilAir), small airways (SmallAir) and alveolar (AlveolAir) primary epithelial cells, cultured at the air-liquid interface. We report that daily administration of escalating doses of FLAMOD for 5 days was well tolerated by epithelia as barrier integrity, cilia motion and cell viability were not affected. FLAMOD was rapidly degraded without leakage into the basal compartment. Each epithelial model exhibited responses involving pathways of innate defense and immune cell infiltration, which were dose-dependent, with an effective concentration of FLAMOD in the picomolar range. Similar tolerance profile and immune responses were obtained with airway epithelium from cystic fibrosis and chronic obstructive pulmonary disease patients. In conclusion, this study supports the stimulation of epithelial Toll-like receptor 5 signaling to fight against infections of vulnerable patients.

cell biology↗

bioRxiv2025

Flagellin nebulization enhances respiratory immune responses in the porcine model

Respiratory delivery of the Toll-like receptor 5 agonist FLAMOD, a recombinant flagellin, offers a promising approach for treating bacterial pneumonia. FLAMOD stimulates the airway epithelium, mobilizing and activating immune cells and effectors to combat infections. While previous evidences were obtained in mouse models, this study represents the first comprehensive assessment of FLAMOD delivered by nebulization in pigs. Our results demonstrate that a single nebulization of FLAMOD did not cause any adverse effects on clinical parameters. Histological analysis supported that FLAMOD treatment led to immune cell infiltration in the lung tissue, indicative of an active immune response. Flow cytometry confirmed granulocyte recruitment in conducting airways. RNA sequencing established immune activation across the respiratory tract, from the nose, trachea, bronchi to the lungs, highlighting innate immunity, bacterial defense, cytokine and chemokine signaling, and granulocyte chemotaxis as key biological pathways. These findings demonstrated the capacity of FLAMOD to induce a robust and common immune response throughout the porcine respiratory system as well as specific compartmentalized immune signatures. This study establishes FLAMOD as a potent activator of innate immunity, providing a proof-of-concept for inhalation-based therapeutic strategies to combat bacterial pneumonia in the clinical setting.

immunology↗

bioRxiv2024

Targeted delivery of flagellin by nebulization offers optimized respiratory immunity and defense against pneumococcal pneumonia

Novel therapeutic strategies are urgently needed to combat pneumonia caused by Streptococcus pneumoniae strains resistant to standard-of-care antibiotics. Previous studies have shown that targeted stimulation of lung innate immune defenses through intranasal administration of the Toll-like receptor 5 agonist flagellin, improves the treatment of pneumonia when combined with antibiotics. To promote translation to the clinic application, this study assessed the direct delivery of flagellin to the airways through nebulization using a vibrating mesh nebulizer in mice. Intranasal delivery achieved approximately 40% lung deposition of the administered flagellin dose, whereas nebulization yielded less than 1%. Despite these differences, nebulized flagellin induced a transient activation of lung innate immunity characterized by cytokine/chemokine production and neutrophil infiltration into airways analogous to intranasal administration. Furthermore, inhalation by nebulization resulted in an accelerated resolution of systemic pro-inflammatory responses. Lastly, adjunct therapy combining nebulized flagellin and amoxicillin proved effective against antibiotic-resistant pneumococcal pneumonia in mice. We posit that flagellin aerosol therapy represents a safe and promising approach to address bacterial pneumonia within the context of antimicrobial resistance.

microbiology↗

bioRxiv2022

An alpaca-derived nanobody neutralizes the SARS-CoV-2 omicron variant

The SARS-CoV2 Omicron variant sub-lineages spread rapidly through the world, mostly due to their immune-evasive properties. This has put a significant part of the population at risk for severe disease and underscores the need for anti-SARS-CoV-2 agents that are effective against emergent strains in vulnerable patients. Camelid nanobodies are attractive therapeutic candidates due to their high stability, ease of large-scale production and potential for delivery via inhalation. Here, we characterize the RBD-specific nanobody W25, which we previously isolated from an alpaca, and show superior neutralization activity towards Omicron lineage BA.1 in comparison to all other SARS-CoV2 variants. Structure analysis of W25 in complex with the SARS-CoV2 spike surface glycoprotein shows that W25 engages an RBD epitope not covered by any of the antibodies previously approved for emergency use. Furthermore, we show that W25 also binds the spike protein from the emerging, more infectious Omicron BA.2 lineage with picomolar affinity. In vivo evaluation of W25 prophylactic and therapeutic treatments across multiple SARS-CoV-2 variant infection models, together with W25 biodistribution analysis in mice, demonstrates favorable pre-clinical properties. Together, these data endorse prioritization of W25 for further clinical development.

microbiology↗

bioRxiv2020

Simultaneous aerosol and intra-muscular immunization with influenza vaccine induces powerful protective local T cell and systemic Ab immune responses in pigs

A vaccine providing both powerful antibody and cross-reactive T cell immune responses against influenza viruses would be beneficial for both humans and pigs. Here we evaluated intramuscular (IM), aerosol (Aer) and simultaneous immunization (SIM) by both routes in pigs, using the single cycle candidate influenza vaccine S-FLU. After prime and boost immunization pigs were challenged with H1N1pdm09 virus. IM immunized pigs generated high titer of neutralizing antibodies but poor T cell responses, while Aer induced powerful respiratory tract T cell responses, but a low titer of antibodies. SIM pigs combined high antibody titers and strong local T cell responses. SIM pigs showed the most complete suppression of virus shedding and the greatest improvement in pathology. We conclude that SIM regimes for immunization against respiratory pathogens warrant further study.

immunology↗

bioRxiv2020

Distribution of droplets and immune responses after aerosol and intra-nasal delivery of influenza virus to the respiratory tract of pigs

Recent evidence indicates that local immune responses and tissue resident memory T cells (TRM) are critical for protection against respiratory infections but there is little information on the contributions of upper and lower respiratory tract (URT and LRT) immunity. To provide a rational basis for designing methods for optimal delivery of vaccines to the respiratory tract in a large animal model, we investigated the distribution of droplets generated by a mucosal atomization device (MAD) and two vibrating mesh nebulizers (VMNs) and the immune responses induced by delivery of influenza virus by MAD in pigs. We showed that droplets containing the drug albuterol, a radiolabel (99mTc-DTPA) or a model influenza virus vaccine (S-FLU) have similar aerosol characteristics. 99mTc-DTPA scintigraphy showed that VMNs deliver droplets with uniform distribution throughout the lungs as well as the URT. Surprisingly MAD administration (1ml/nostril) also delivered a high proportion of the dose to the lungs, albeit concentrated in a small area. After MAD administration of influenza virus, antigen specific T cells were found at high frequency in nasal turbinates, trachea, broncho-alveolar lavage, lungs, tracheobronchial nodes and blood. We conclude that the pig is useful for investigating optimal targeting of vaccines to the respiratory tract.

immunology↗