C5aR1 activation in mice controls inflammatory eosinophil recruitment and functions in allergic asthma

Anna V. Wiese, Jannis Duhn, Rabia Ülkü Korkmaz, Katharina M. Quell, Ibrahim Osman, Fanny Ender, Torsten Schröder, Ian Lewkowich, Simon Hogan, Markus Huber-Lang, Franziska Gumprecht, Peter König, Jörg Köhl*, Yves Laumonnier*

*Corresponding author for this work
1 Citation (Scopus)

Abstract

Background: Pulmonary eosinophils comprise at least two distinct populations of resident eosinophils (rEOS) and inflammatory eosinophils (iEOS), the latter recruited in response to pulmonary inflammation. Here, we determined the impact of complement activation on rEOS and iEOS trafficking and function in two models of pulmonary inflammation. Methods: BALB/c wild-type and C5ar1−/− mice were exposed to different allergens or IL-33. Eosinophil populations in the airways, lung, or mediastinal lymph nodes (mLN) were characterized by FACS or immunohistochemistry. rEOS and iEOS functions were determined in vivo and in vitro. Results: HDM and IL-33 exposure induced a strong accumulation of iEOS but not rEOS in the airways, lungs, and mLNs. rEOS and iEOS expressed C3/C5 and C5aR1, which were significantly higher in iEOS. Initial pulmonary trafficking of iEOS was markedly reduced in C5ar1−/− mice and associated with less IL-5 production from ILC2 cells. Functionally, adoptively transferred pulmonary iEOS from WT but not from C5ar1−/− mice-induced airway hyperresponsiveness (AHR), which was associated with significantly reduced C5ar1−/− iEOS degranulation. Pulmonary iEOS but not rEOS were frequently associated with T cells in lung tissue. After HDM or IL-33 exposure, iEOS but not rEOS were found in mLNs, which were significantly reduced in C5ar1−/− mice. C5ar1−/− iEOS expressed less costimulatory molecules, associated with a decreased potency to drive antigen-specific T cell proliferation and differentiation into memory T cells. Conclusions: We uncovered novel roles for C5aR1 in iEOS trafficking and activation, which affects key aspects of allergic inflammation such as AHR, ILC2, and T cell activation.

Original languageEnglish
JournalAllergy: European Journal of Allergy and Clinical Immunology
Volume78
Issue number7
Pages (from-to)1893-1908
Number of pages16
ISSN0105-4538
DOIs
Publication statusPublished - 07.2023

Research Areas and Centers

  • Academic Focus: Center for Infection and Inflammation Research (ZIEL)

DFG Research Classification Scheme

  • 204-05 Immunology
  • 205-22 Clinical Immunology and Allergology

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