AUTHOR=Goplen Nick P. , Cheon In Su , Sun Jie 

TITLE=Age-Related Dynamics of Lung-Resident Memory CD8+ T Cells in the Age of COVID-19

JOURNAL=Frontiers in Immunology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.636118

DOI=10.3389/fimmu.2021.636118

ISSN=1664-3224

ABSTRACT=<p>Following respiratory viral infections or local immunizations, lung resident-memory T cells (T<sub>RM</sub>) of the CD8 lineage provide protection against the same pathogen or related pathogens with cross-reactive T cell epitopes. Yet, it is now clear that, if homeostatic controls are lost following viral pneumonia, CD8 T<sub>RM</sub> cells can mediate pulmonary pathology. We recently showed that the aging process can result in loss of homeostatic controls on CD8 T<sub>RM</sub> cells in the respiratory tract. This may be germane to treatment modalities in both influenza and coronavirus disease 2019 (COVID-19) patients, particularly, the portion that present with symptoms linked to long-lasting lung dysfunction. Here, we review the developmental cues and functionalities of CD8 T<sub>RM</sub> cells in viral pneumonia models with a particular focus on their capacity to mediate heterogeneous responses of immunity and pathology depending on immune status.</p>