Following clearance of viral infection memory T cells are retained to protect the host from reinfection. Central memory (CM) T cells efficiently migrate within the loose network of fibroblastic reticular cells inside the lymph node (LN) parenchyma and monitor antigen presenting cells for cognate antigen. Tissue-resident effector memory (EM) T cells cope with the denser environment within peripheral organs, migrating between endo- and epithelial cells and dense extracellular matrix. Little is known about migration behavior and mechanisms required for EM T cell tissue surveillance. In this study we compare the migratory behavior of CM and EM T cells within the same mouse by consecutive multiphoton intravital imaging of the popliteal LN and the salivary gland (SG), respectively. We establish intravital imaging of the SG as a model for a peripheral organ harboring tissue-resident effector memory cells in between the tightly packaged endo- and epithelial cells. Comparison of the migratory behavior of cognate T cells during the acute and the memory phase of a LCMV infection revealed efficient migration of effector T cells within the SG at all timepoints, although with reduced velocity compared to the LN parenchyma. During the memory phase of infection EM T cells show a probing phenotype, projecting dendrites in between the epithelial cells. Using the ROCK-inhibitor Y27632 and DOCK8-deficient T cells we refine the picture of EM T cell migration within peripheral organs.
- Copyright © 2013 by The American Association of Immunologists, Inc.