Streptococcus pneumoniae is the most common etiology of bacterial pneumonia, one of the leading causes of death in children and the elderly worldwide. During non-lethal infections with S. pneumoniae, lymphocytes accumulate in the lungs and protect against reinfection with serotype-mismatched strains. Cluster of differentiation CD4^{+} resident memory T (T_{RM}) cells are known to be crucial for this protection, but the diversity of lung CD4^{+} T_{RM} cells has yet to be fully delineated. We aimed to identify unique subsets and their contributions to lung immunity. After recovery from pneumococcal infections, we identified a distinct subset of CD4^{+} T cells defined by the phenotype CD11a^{hi}CD69^{+}GL7^{+} in mouse lungs. Phenotypic analyses for markers of lymphocyte memory and residence demonstrated that GL7^{+} T cells are a subset of CD4^{+} T_{RM} cells. Functional studies revealed that unlike GL7^{-} T_{RM} subsets that were mostly (RAR-related Orphan Receptor gamma T) RORγT^{+}, GL7^{+} T_{RM} cells exhibited higher levels of (T-box expressed in T cells) T-bet and Gata-3, corresponding with increased synthesis of interferon-γ, interleukin-13, and interleukin-5, inherent to both T helper 1 (T_{H}1) and T_{H}2 functions. Thus, we propose that these cells provide novel contributions during pneumococcal pneumonia, serving as important determinants of lung immunity.
GL7 ligand expression defines a novel subset of CD4+ TRM cells in lungs recovered from pneumococcus
[Category] 폐렴구균 감염증,
[Article Type] article
[Source] pubmed
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