Cytotoxic Mechanisms Employed by Mouse T Cells to Destroy Pancreatic β-Cells

  1. Alexander V. Chervonsky
  1. Department of Pathology, University of Chicago, Chicago, Illinois
  1. Corresponding author: Alexander V. Chervonsky, achervon{at}bsd.uchicago.edu.

Abstract

Several cytotoxic mechanisms have been attributed to T cells participating in β-cell death in type 1 diabetes. However, sensitivity of β-cells to these mechanisms in vitro and in vivo is likely to be different. Moreover, CD4+ and CD8+ T cells may use distinct mechanisms to cause β-cell demise that possibly involve activation of third-party cytotoxic cells. We used the transfer of genetically modified diabetogenic T cells into normal, mutant, and bone marrow chimeric recipients to test the contribution of major cytotoxic mechanisms in β-cell death. We found that 1) the killing of β-cells by CD4+ T cells required activation of the recipient’s own cytotoxic cells via tumor necrosis factor-α (TNF-α); 2) CD8+ T-cell cytotoxic mechanisms destroying β-cells were limited to perforin and Fas ligand, as double knockouts of these molecules abrogated the ability of T cells to cause diabetes; and 3) individual CD8+ T-cell clones chose their cytotoxic weaponry by a yet unknown mechanism and destroyed their targets via either Fas-independent or Fas-dependent (∼40% of clones) pathways. Fas-dependent destruction was assisted by TNF-α.

Footnotes

  • Received December 21, 2011.
  • Accepted May 1, 2012.

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  1. Diabetes vol. 61 no. 11 2862-2870
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