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Updated: Aug 9, 2026

HLA-Ig Based Artificial Antigen Presenting Cells for Efficient ex vivo Expansion of Human CTL
07:18

HLA-Ig Based Artificial Antigen Presenting Cells for Efficient ex vivo Expansion of Human CTL

Published on: April 11, 2011

A novel approach to antigen-specific deletion of CTL with minimal cellular activation using alpha3 domain mutants of

X N Xu1, M A Purbhoo, N Chen

  • 1MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, Headington, OX3 9DS, Oxford, United Kingdom. xiaoning@molbiol.ox.ac.uk

Immunity
|May 24, 2001
PubMed

Insights

Blocking CD8 binding on T cells surprisingly maintains FasL expression and T cell apoptosis, even with reduced signaling and killing. This finding may enable targeted deletion of harmful T cells without full activation side effects.

Area of Science:

  • Immunology
  • Cellular Biology
  • Molecular Medicine

Background:

  • Cytotoxic T lymphocytes (CTLs) are crucial for adaptive immunity.
  • CTL effector functions, including target cell killing and apoptosis, are mediated through T cell receptor (TCR) and CD8 coreceptor interactions.
  • Understanding the precise mechanisms regulating CTL activation and apoptosis is vital for immunotherapy.

Purpose of the Study:

  • To compare effector functions and fate of human CTL clones upon interaction with variant peptides.
  • To investigate the role of CD8 coreceptor binding in TCR signaling, target cell killing, and CTL apoptosis.
  • To explore the potential for dissociating CTL activation pathways for therapeutic benefit.

Main Methods:

  • In vitro and ex vivo analysis of human CTL clones.
  • Utilized variant peptides presented on cell surfaces and in soluble multimeric formats.
  • Employed alpha3 domain mutants of MHC class I to block CD8 binding.
  • Assessed TCR signaling, target cell killing, and FasL-mediated CTL apoptosis.

Main Results:

  • CD8 coreceptor binding correlated well with TCR signaling, target cell killing, and CTL apoptosis.
  • Blocking CD8 binding significantly reduced TCR signaling and target cell killing.
  • Surprisingly, FasL expression and CTL apoptosis remained largely unaffected when CD8 binding was blocked.

Conclusions:

  • CD8 coreceptor engagement is not strictly required for FasL induction and subsequent CTL apoptosis.
  • The ability to decouple CTL signaling/killing from apoptosis opens possibilities for selective elimination of antigen-specific CTLs.
  • This dissociation may offer a therapeutic strategy to remove pathological CTL populations without causing detrimental effects associated with full CTL activation.

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