Visualization of T Cell Migration in the Spleen Reveals a Network of Perivascular Pathways that Guide Entry into T Zones

Immunity. 2020 May 19;52(5):794-807.e7. doi: 10.1016/j.immuni.2020.03.010. Epub 2020 Apr 15.

Abstract

Lymphocyte homeostasis and immune surveillance require that T and B cells continuously recirculate between secondary lymphoid organs. Here, we used intravital microscopy to define lymphocyte trafficking routes within the spleen, an environment of open blood circulation and shear forces unlike other lymphoid organs. Upon release from arterioles into the red pulp sinuses, T cells latched onto perivascular stromal cells in a manner that was independent of the chemokine receptor CCR7 but sensitive to Gi protein-coupled receptor inhibitors. This latching sheltered T cells from blood flow and enabled unidirectional migration to the bridging channels and then to T zones, entry into which required CCR7. Inflammatory responses modified the chemotactic cues along the perivascular homing paths, leading to rapid block of entry. Our findings reveal a role for vascular structures in lymphocyte recirculation through the spleen, indicating the existence of separate entry and exit routes and that of a checkpoint located at the gate to the T zone.

Keywords: GPCRs; T cells; bridging channels; intravital imaging; lymphocyte trafficking; spleen; vascular-guided migration.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • B-Lymphocytes / cytology
  • B-Lymphocytes / immunology
  • B-Lymphocytes / metabolism
  • Cell Movement / immunology*
  • Humans
  • Immunologic Surveillance / immunology
  • Intravital Microscopy
  • Luminescent Proteins / genetics
  • Luminescent Proteins / metabolism
  • Lymphocytes / cytology
  • Lymphocytes / immunology
  • Lymphocytes / metabolism
  • Mice, Inbred C57BL
  • Mice, Transgenic
  • Receptors, CCR7 / genetics
  • Receptors, CCR7 / immunology*
  • Receptors, CCR7 / metabolism
  • Signal Transduction / immunology
  • Spleen / cytology
  • Spleen / immunology*
  • Spleen / metabolism
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism

Substances

  • Luminescent Proteins
  • Receptors, CCR7