Abstract
T cell activation is driven by the TCR and complemented by costimulation. We have studied the dynamics of ligand-engagement of the costimulatory receptor CD2 in T cell/APC couples. Thousands of ligand-engaged CD2 molecules were included in a large T cell invagination at the center of the cellular interface within l min of cell couple formation. The structure and regulation of this invagination shared numerous features with phagocytosis and macropinocytosis. Tnree observations further characterize the invagination and the inclusion of CD2: 1) numerous ligand-engaged receptors were enriched in and internalized through the T cell invagination, none as prominently as CD2; 2) dissolution of the T cell invagination and CD2 engagement were required for effective proximal T cell signaling; and 3) the T cell invagination was uniquely sensitive to the affinity of the TCR for peptide-MHC. Based on this characterization, we speculate that the T cell invagination, aided by CD2 enrichment, internalizes parts of the TCR signaling machinery to reset T cell signaling upon agonist-mediated, stable APC contact.
Original language | English (US) |
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Pages (from-to) | 4402-4413 |
Number of pages | 12 |
Journal | Journal of Immunology |
Volume | 177 |
Issue number | 7 |
DOIs | |
State | Published - Oct 1 2006 |
ASJC Scopus subject areas
- Immunology and Allergy
- Immunology