CD103hi lung-resident regulatory T cells constrain the fibrotic responses induced by CD103low tissue-resident pathogenic CD4 T cells

Tissue-resident memory T (TRM) cells are crucial mediators of adaptive immunity in non-lymphoid tissues. However, the functional heterogeneity and pathogenic roles of CD4+ TRM cells that reside within chronic inflammatory lesions remain unknown. We found that CD69hiCD103low CD4+ TRM cells produced effector cytokines and promoted the inflammation and fibrotic responses induced by chronic exposure to Aspergillus fumigatus. Simultaneously, immunosuppressive CD69hiCD103hiFoxp3+ CD4+ regulatory T (Treg) cells were induced and constrained the ability of pathogenic CD103low TRM cells to cause fibrosis. Thus, lung tissue-resident CD4+ T cells play crucial roles in the pathology of chronic lung inflammation, and CD103 expression defines pathogenic effector and immunosuppressive tissue-resident cell subpopulations in the inflamed lung. Overall design: T cells in lung treated with Aspergillus antigen are assessed by RNA-seq and ATAC-Seq.