GL7 ligand expression defines a novel subset of CD4⁺ T_RM cells in lungs recovered from pneumococcus.

ABSTRACT: 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^hiCD69⁺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_H1) and T_H2 functions. Thus, we propose that these cells provide novel contributions during pneumococcal pneumonia, serving as important determinants of lung immunity.

SUBMITTER: Lyon De Ana C 

PROVIDER: S-EPMC10591822 | biostudies-literature | 2023 Oct

REPOSITORIES: biostudies-literature