ABSTRACT
Tissue-resident memory T cells (Trm) are retained in peripheral tissues after infection for enhanced protection against secondary encounter with the same pathogen. We have previously shown that the transcription factor Hobit and its homolog Blimp-1 drive Trm development after viral infection, but how and when these transcription factors mediate Trm formation remains poorly understood. In particular, the major impact of Blimp-1 in regulating several aspects of effector T-cell differentiation impairs study of its specific role in Trm development. Here, we used the restricted expression of Hobit in the Trm lineage to develop mice with a conditional deletion of Blimp-1 in Trm, allowing us to specifically investigate the role of both transcription factors in Trm differentiation. We found that Hobit and Blimp-1 were required for the upregulation of CD69 and suppression of CCR7 and S1PR1 on virus-specific Trm precursors after LCMV infection, underlining a role in their retention within tissues. The early impact of Hobit and Blimp-1 favored Trm formation and prevented the development of circulating memory T cells. Thus, our findings highlight a role of Hobit and Blimp-1 at the branching point of circulating and resident memory lineages by suppressing tissue egress of Trm precursors early during infection.
Subject(s)
CD8-Positive T-Lymphocytes , Immunologic Memory , Lymphocytic Choriomeningitis , Lymphocytic choriomeningitis virus , Positive Regulatory Domain I-Binding Factor 1 , Transcription Factors , Animals , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , CD8-Positive T-Lymphocytes/pathology , Lymphocytic Choriomeningitis/immunology , Lymphocytic Choriomeningitis/pathology , Lymphocytic choriomeningitis virus/immunology , Mice , Positive Regulatory Domain I-Binding Factor 1/immunology , Transcription Factors/genetics , Transcription Factors/immunology , Transcription Factors/metabolismABSTRACT
Innate lymphoid cells (ILCs) are crucial for the immune surveillance at mucosal sites. ILCs coordinate early eradication of pathogens and contribute to tissue healing and remodeling, features that are dysfunctional in patients with cystic fibrosis (CF). The mechanisms by which ILCs contribute to CF-immunopathology are ill-defined. Here, we show that group 2 ILCs (ILC2s) transdifferentiated into IL-17-secreting cells in the presence of the epithelial-derived cytokines IL-1ß, IL-23 and TGF-ß. This conversion is abrogated by IL-4 or vitamin D3. IL-17 producing ILC2s induce IL-8 secretion by epithelial cells and their presence in nasal polyps of CF patients is associated with neutrophilia. Our data suggest that ILC2s undergo transdifferentiation in CF nasal polyps in response to local cytokines, which are induced by infectious agents.
