Daily Respiratory Research Analysis
Analyzed 271 papers and selected 3 impactful papers.
Summary
Analyzed 271 papers and selected 3 impactful articles.
Selected Articles
1. B cell αv integrin regulates tissue specialization and clonal expansion of lung germinal center and memory B cells after viral infection.
This mechanistic study shows that B cell–intrinsic αv integrin restrains germinal center persistence and the expansion of lung-resident memory B cells after influenza A infection. B cell–specific αv deletion sustains iBALT germinal centers and increases lung memory B cells, including IgA-producing subsets, highlighting a tissue-specific brake on mucosal humoral memory.
Impact: Revealing a B cell–intrinsic integrin pathway that programs lung-resident humoral memory opens avenues for mucosal vaccine design and local immunity modulation against respiratory viruses.
Clinical Implications: Although preclinical, targeting αv integrin on B cells could be leveraged to enhance or fine-tune mucosal antibody memory (e.g., IgA) in the lung, potentially improving durability and breadth of respiratory virus vaccines.
Key Findings
- B cell–intrinsic αv integrin is a negative regulator of lung germinal center dynamics after influenza A infection.
- B cell–specific αv knockout leads to persistent iBALT germinal center activity.
- Loss of B cell αv integrin expands lung-resident memory B cells, including IgA-producing subsets.
Methodological Strengths
- Cell type–specific genetic knockout to establish causality in vivo
- Tissue-resident immune compartment analysis in the lung following infection
Limitations
- Findings are preclinical and derived from mouse models
- Mechanistic links to human mucosal immunity and vaccine responses require validation
Future Directions: Test whether pharmacologic or genetic modulation of αv integrin on B cells enhances mucosal vaccine efficacy and durability in diverse respiratory virus models and in human tissues.
Lung-resident B cells are increasingly recognized as key contributors to protective immunity against respiratory viruses, yet the mechanisms that govern their generation and specialization remain poorly understood. Here, we identify B cell-intrinsic αv integrin as a critical negative regulator of germinal center (GC) dynamics and memory B cell formation in the lung following influenza A virus infection. Using B cell-specific αv knockout mice, we show that loss of B cell αv integrin leads to persistent GC activity within the inducible bronchus-associated lymphoid tissue and expansion of lung-resident memory B cells, including IgA
2. Bacterial targeting of the neutrophil inhibitory receptor LILRB3 to evade antibody immunity.
This mechanistic study demonstrates that Streptococcus agalactiae exploits the neutrophil inhibitory receptor LILRB3 via its surface β protein to suppress Fc receptor–mediated respiratory burst and bacterial killing. The finding provides a clear immune-evasion pathway linked to invasive lineages in older adults, revealing a potential target to restore antibody-dependent neutrophil defense.
Impact: Reveals a previously unrecognized receptor–ligand mechanism by which a common human pathogen blunts antibody-driven neutrophil effector functions. This advances fundamental understanding of antibacterial immunity with translational potential for therapeutics or vaccines.
Clinical Implications: Blocking β–LILRB3 interactions or modulating LILRB3 signaling could enhance antibody-dependent neutrophil killing, particularly in elderly or immunocompromised patients with invasive Group B Streptococcus infections.
Key Findings
- S. agalactiae β protein binds and cross-links neutrophil LILRB3, triggering inhibitory signaling.
- Engagement of LILRB3 suppresses Fc receptor–mediated respiratory burst and antibody-dependent bacterial killing.
- β expression and LILRB3 targeting associate with invasive disease lineages prevalent in older adults.
Methodological Strengths
- Mechanistic delineation linking receptor–ligand binding to specific neutrophil effector outcomes.
- Integration of molecular binding studies with functional assays of respiratory burst and killing, and lineage association.
Limitations
- Primarily in vitro and ex vivo mechanistic work; in vivo validation in human infection models is lacking.
- Therapeutic blockade of β–LILRB3 was not tested preclinically.
Future Directions: Evaluate β–LILRB3 blockade in relevant in vivo models and assess whether LILRB3 pathway modulation restores neutrophil function and improves outcomes in invasive streptococcal disease.
Antibody-mediated responses are critical for antibacterial immunity, driving Fc receptor-mediated phagocytosis, respiratory burst, and bacterial killing. Inhibitory immune receptors regulate cellular activation and immune homoeostasis, but whether they are targeted to evade antibody-mediated responses is unclear. Here, we show that the highly expressed inhibitory LILRB3 receptor on neutrophils is targeted by Streptococcus agalactiae to suppress antibody-driven defence. We show that the surface-localised β protein of S. agalactiae bound to LILRB3 and induced its cross-linking. β and LILRB3 interactions suppressed Fc receptor-mediated antibacterial responses such as respiratory burst and bacterial killing, inhibiting antibody-dependent bacterial killing by neutrophils. Moreover, β expression and LILRB3 targeting are associated with S. agalactiae lineages that cause invasive diseases in older adults, indicating that targeting inhibitory receptors most likely provides an immune evasion mechanism when antibody responses are waning, such as in immunocompromised or elderly individuals. Altogether, these results highlight a simple and important mechanism that bacterial pathogens utilise to overcome effective antibody-driven phagocyte responses.
3. Wastewater-based sequencing of respiratory syncytial virus to investigate lineage dynamics and antigenic site mutations: a retrospective genomic epidemiology study.
Amplicon-based sequencing of 64 wastewater composites from Zurich and Geneva across two RSV seasons revealed dominance of RSV-B B.D.E.1 in 2022–23 and cocirculation of multiple RSV-A lineages in 2023–24. Low-frequency nonsynonymous mutations in fusion-protein antigenic sites were identified, demonstrating wastewater genomics as a practical tool to monitor lineage dynamics and mutations relevant to immunoprophylaxis.
Impact: Provides an operationally scalable, population-level genomic surveillance approach for RSV that captures lineage shifts and antigenic-site mutations outside of clinical sampling frames.
Clinical Implications: Wastewater genomic data can complement clinical surveillance to anticipate lineage turnover and potential antigenic drift that may influence effectiveness of monoclonal antibodies or vaccines.
Key Findings
- RSV-B lineage B.D.E.1 predominated in 2022–23, while multiple RSV-A lineages (A.D.1, A.D.3, A.D.5 and sub-lineages) cocirculated in 2023–24.
- Low-frequency nonsynonymous mutations were detected in fusion (F) protein antigenic sites for both RSV-A and RSV-B.
- Lineage relative abundances were inferred from lineage-signature mutation frequencies using a read-depth threshold (>30) and >90% lineage-defining criteria.
Methodological Strengths
- City-scale, longitudinal wastewater sampling across consecutive seasons with subtype-specific amplicon sequencing.
- Objective lineage quantification using lineage-signature mutations and defined depth thresholds.
Limitations
- Limited geographic scope (two Swiss cities) and sample number may miss finer-grained within-season dynamics.
- Wastewater signal integrates multiple sources; direct linkage to clinical incidence was not established.
Future Directions: Scale to multicenter networks with integrated clinical correlates, and prospectively evaluate mutation tracking against immunoprophylaxis roll-outs.
BACKGROUND: Respiratory syncytial virus (RSV) infections pose a substantial health burden, particularly for clinically vulnerable populations such as infants and older adults. Although novel immunoprophylactic interventions show promise in providing protection, many countries may not have robust surveillance systems to monitor circulating RSV lineages and detect mutations that might reduce the effectiveness of these new interventions. We aimed to assess the diversity and temporal dynamics of circulating RSV lineages in urban populations through amplicon-based sequencing and analysis of wastewater extracts. METHODS: In this prospective observational wastewater-based genomic surveillance study, 32 raw influent 24-h composite samples were collected during the 2022-23 and 2023-24 RSV seasons from both Zurich and Geneva, Switzerland. We applied an RSV subtype-specific amplicon-based sequencing approach to obtain RSV-A and RSV-B sequences from all 64 samples. Mutations relative to reference genomes were identified at positions with read depth above 30. Relative abundances of RSV lineages were estimated from frequencies of lineage-signature mutations, present in greater than 90% of publicly available sequences of that lineage. FINDINGS: Relative abundances of RSV-B (2022-23) and RSV-A (2023-24) lineages were estimated over the two RSV seasons. During the 2022-23 season, the RSV-B B.D.E.1 lineage prevailed in both cities. In the 2023-24 season, multiple RSV-A lineages cocirculated, including A.D.1, A.D.3, A.D.5, and their sub-lineages. Identification and frequency estimation of mutations showed low-frequency, non-synonymous mutations in antigenic sites on the fusion gene of both RSV-A and RSV-B, some of which have not been reported in clinical sequences. The primary outcome was identification and relative abundance of RSV lineages in wastewater samples. INTERPRETATION: These findings show the potential of wastewater-based genomic surveillance to identify and track circulating RSV lineages and clinically relevant mutations. As novel RSV immunoprophylaxis measures are introduced in upcoming RSV seasons, wastewater-derived genomic RSV data provide a valuable baseline for understanding RSV diversity and future viral evolution under increased immunological pressure. FUNDING: This study was funded by the Swiss National Science Foundation and in part by the National Institute Of Allergy And Infectious Diseases of the National Institutes of Health. Funding for sample collection and processing was provided by the Swiss Federal Office of Public Health.