Early immune signals may shape long-term lung inflammation by programming how tissues respond to future exposures.
Excessive inflammation underpins many allergic and autoimmune conditions, but while immunological memory is well characterised, how tissue-resident cells shape long-term inflammatory responses remains less clear.
This latest study explored protease hypersensitivity in the lungs, uncovering a mechanism by which initial immune responses can either amplify or suppress future allergic reactions.
Lung Inflammation Altered by Early Immune Signals
Using a mouse model of acute lung protease hypersensitivity, researchers examined how exposure to a protease allergen triggered a type 2 immune response, commonly linked to allergic conditions such as asthma.
They found that when this response was counteracted early by a type 1 immune signal – induced using Toll-like receptor ligands or bacterial components – the typical eosinophilic inflammation was markedly reduced.
The findings showed that early immune cross-regulation played a decisive role in controlling protease hypersensitivity. Mice exposed to this protective type 1 response did not develop the usual eosinophilic inflammation upon later re-exposure to the allergen.
In contrast, those without this early modulation experienced heightened allergic inflammation weeks later.
This suggests that the nature of the initial immune response determines whether protease hypersensitivity becomes amplified or suppressed over time. Such insights are particularly relevant for understanding chronic allergic diseases, where repeated exposures can worsen symptoms.
Cellular Memory Drives Protease Hypersensitivity Outcomes
Crucially, the study identified lung stromal cells as key players in storing this immunological memory. These cells exhibited long-term changes in gene accessibility, particularly in the Ccl11 gene, which is linked to eosinophil recruitment. This epigenetic reprogramming depended on interleukin-4 and interleukin-13 signalling and was inhibited by interferon gamma.
This discovery highlights that protease hypersensitivity is not solely governed by immune cells but also by structural cells within tissues that retain a “memory” of past inflammation.
While the study was conducted in mice, the implications are significant. It suggests that early-life exposures or interventions could shape long-term susceptibility to allergic disease by modifying how tissues respond to future insults.
Further research is needed to determine whether similar mechanisms operate in humans. However, these findings open new avenues for preventing chronic inflammation by targeting early immune responses and tissue-level memory.
Reference
Ryu J et al. Long-term inhibition of protease hypersensitivity by initial immunological cross-regulation and epigenetic memory in lung stromal cells. Nat Immunol. 2026; DOI:10.1038/s41590-026-02439-0.
Featured image: Jenjira on Adobe Stock
