Reversal of the TCR stop signal by CTLA-4

J.M. Brewer, Helga Schneider, Jos Downey, Andrew Smith, B.H. Zinselmeyer, Catherine Rush

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The coreceptor cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) is pivotal in regulating the threshold of signals during T cell activation, although the underlying mechanism is still not fully understood. Using in vitro migration assays and in vivo two-photon laser scanning microscopy, we showed that CTLA-4 increases T cell motility and overrides the T cell receptor (TCR)-induced stop signal required for stable conjugate formation between T cells and antigen-presenting cells. This event led to reduced contact periods between T cells and antigen-presenting cells that in turn decreased cytokine production and proliferation. These results suggest a fundamentally different model of reverse stop signaling, by which CTLA-4 modulates the threshold for T cell activation and protects against autoimmunity.
Original languageEnglish
Pages (from-to)1972-1975
Number of pages3
Issue number5795
Publication statusPublished - 2006


  • biophotonics
  • cells
  • microscopy
  • lasers
  • t cells

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