[PDF][PDF] Increased TCR avidity after T cell activation: a mechanism for sensing low-density antigen

TM Fahmy, JG Bieler, M Edidin, JP Schneck - Immunity, 2001 - cell.com
TM Fahmy, JG Bieler, M Edidin, JP Schneck
Immunity, 2001cell.com
While activated T cells are known to have enhanced biological responses to antigen
stimulation, the biophysical basis of this increased sensitivity remains unknown. Here, we
show that, on activated T cells, the TCR avidity for peptide-MHC complexes is 20-to 50-fold
higher than the TCR avidity of naive T cells. This increased avidity for peptide-MHC depends
on TCR reorganization and is sensitive to the cholesterol content of the T cell membrane.
Analysis of the binding data indicates the enhanced avidity is due to increases in cross …
Abstract
While activated T cells are known to have enhanced biological responses to antigen stimulation, the biophysical basis of this increased sensitivity remains unknown. Here, we show that, on activated T cells, the TCR avidity for peptide-MHC complexes is 20- to 50-fold higher than the TCR avidity of naive T cells. This increased avidity for peptide-MHC depends on TCR reorganization and is sensitive to the cholesterol content of the T cell membrane. Analysis of the binding data indicates the enhanced avidity is due to increases in cross-linking of TCR on activated T cells. Activation-induced membrane (AIM) changes in TCR avidity represent a previously unrecognized means of increasing the sensitivity of activated T cells to small amounts of antigen in the periphery.
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