Human cytotoxic T lymphocytes with reduced sensitivity to Fas-induced apoptosis

Blood. 2005 Jun 15;105(12):4677-84. doi: 10.1182/blood-2004-08-3337. Epub 2005 Feb 15.


Effector-memory T cells expressing Fas (Apo-1/CD95) are switched to an apoptotic program by cross-linking with Fas-ligand (FasL). Consequently, tumors that express FasL can induce apoptosis of infiltrating Fas-positive T lymphocytes and subdue any antitumor host immune response. Since Epstein-Barr virus (EBV)-associated tumors such as Hodgkin lymphoma (HL) and nasopharyngeal carcinoma (NPC) express FasL, we determined whether EBV-specific cytotoxic T lymphocytes (EBV-CTLs) could be modified to resist this evasion strategy. We show that long-term down-modulation of Fas can be achieved in EBV-CTLs by transduction with small interfering RNA (siRNA) encoded in a retrovirus. Modified T cells resisted Fas/FasL-mediated apoptosis compared with control cells and showed minimal cleavage of the caspase3 substrate poly(ADP-ribose) polymerase (PARP) protein after Fas engagement. Prolonged Fas stimulation selected a uniformly Fas(low) and FasL resistant population. Removal of responsiveness to this single death signal had no other discernible effects on EBV-CTLs. In particular, it did not lead to their autonomous growth since the modified EBV-CTLs remained polyclonal, and their survival and proliferation retained dependence on antigen-specific stimulation and on the presence of other physiologic growth signals. EBV-CTLs with knocked down Fas should have a selective functional and survival advantage over unmodified EBV-CTLs in the presence of tumors expressing FasL and may be of value for adoptive cellular therapy.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Antigens / metabolism
  • Apoptosis*
  • Blotting, Western
  • CD3 Complex / biosynthesis
  • COS Cells
  • Caspase 3
  • Caspases / metabolism
  • Cell Death
  • Cell Line
  • Cell Proliferation
  • Cell Survival
  • Chromium / metabolism
  • Down-Regulation
  • Enzyme-Linked Immunosorbent Assay
  • Fas Ligand Protein
  • Humans
  • Immunophenotyping
  • Interferon-gamma / metabolism
  • Jurkat Cells
  • Membrane Glycoproteins / metabolism
  • Plasmids / metabolism
  • Poly(ADP-ribose) Polymerases / metabolism
  • RNA, Small Interfering / metabolism
  • Retroviridae / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • T-Lymphocytes / metabolism
  • T-Lymphocytes, Cytotoxic / immunology*
  • T-Lymphocytes, Cytotoxic / metabolism
  • fas Receptor / biosynthesis
  • fas Receptor / metabolism*


  • Antigens
  • CD3 Complex
  • FASLG protein, human
  • Fas Ligand Protein
  • Membrane Glycoproteins
  • RNA, Small Interfering
  • fas Receptor
  • Chromium
  • Interferon-gamma
  • Poly(ADP-ribose) Polymerases
  • CASP3 protein, human
  • Caspase 3
  • Caspases