Type-2-immune history imprints local training in nerve-airway associated interstitial macrophages (NAMs) for disease tolerance during respiratory viral infection

Using NAM-DTR mice, we show that conditioned NAMs are necessary and sufficient for protection: depletion or replacement with unconditioned NAMs abrogated survival, whereas adoptive transfer of conditioned NAMs conferred tolerance without enhancing viral clearance. Genomic analyses implicated an IL-4–STAT6–PPARγ and Arginase-1 chromatin program that imprints a pro-resolving and reparative NAM state driving programs of tissue repair, type 2 immunity and efferocytosis during lethal respiratory viral infections.

Finally, meta-analysis of human lung single-cell atlases from healthy, IPF and COPD cohorts indicated that reparative NAM-like programs aligned with fibrotic remodeling in IPF but diverged in COPD, supporting context-dependent consequences of sustained repair states. These findings establish local trained immunity in lung-resident macrophages as a mechanism of disease tolerance and a therapeutic entry point for severe inflammatory respiratory infections.