Without peripheral interference, thymic deletion is mediated in a cohort of double-positive cells without classical activation
Details
Publication Year 2003-02-04,Volume 100,Issue #3,Page 1197-1202
Journal Title
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
Publication Type
Journal Article
Abstract
Peripheral activation can cause bystander thymocyte death by eliciting a "cytokine storm." This event complicates in vivo studies using exogenous ligand-induced models of negative selection. A stable transgenic model that selectively eliminates peripheral CD4 cells has allowed us to analyze negative selection as direct cognate events in two T cell receptor transgenic mice, OT-II and DO11. Whereas cognate peptide induced a massive deletion in double-positive (DP) cells in mice with peripheral CD4 cells, this DP deletion was modest in mice lacking peripheral CD4 cells. Using BrdUrd and annexin V staining, we found that negative selection primarily occurs in a cohort of DP cells and the absence of single-positive (SP) cells is largely caused by reduction in the cohort of DP precursors. Moreover, the fates of DP cells and SP cells after antigen exposure were vastly different. Whereas SP cells up-regulated uniformly their CD69 and CD44 levels, increased their cell size, and survived after antigen exposure, DP cells had less CD69 and CD44 up-regulation, no size change, and promptly died. Thus, negative selection represents an "abortive" activation different from activation-induced cell death of mature T cells.
Publisher
NATL ACAD SCIENCES
Keywords
RECEPTOR TRANSGENIC MICE; MAJOR HISTOCOMPATIBILITY COMPLEX; T-CELLS; NEGATIVE SELECTION; THYMOCYTE SELECTION; ANTIGEN; APOPTOSIS; EXPRESSION; TOLERANCE; CD4
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Creation Date: 2003-02-04 12:00:00
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