CD28 costimulation Impairs the efficacy of a redirected t-cell antitumor attack in the presence of regulatory t cells which can be overcome by preventing Lck activation

Mol Ther. 2011 Apr;19(4):760-7. doi: 10.1038/mt.2011.9. Epub 2011 Feb 15.


Adoptive T-cell transfer showed promising efficacy in recent trials raising interest in T cells with redirected specificity against tumors. T cells were engineered with a chimeric antigen receptor (CAR) with predefined binding and CD3ζ signaling to initiate T-cell activation. CD28 costimulation provided by a CD28-CD3ζ signaling CAR moreover improved T cell activation and persistence; however, it failed to meet the expectations with respect to mounting attacks against solid tumors infiltrated with regulatory T (Treg) cells. We revealed that a CD28 CAR-redirected T-cell attack is accompanied by higher numbers of Treg cells infiltrating the tumor and is less efficient against cancer cells in presence of Treg cells than a CD3ζ CAR T-cell attack. Deletion of the lck binding moiety in the CD28 CAR endodomain, however, improved redirected anti-tumor activity in presence of Treg cells without impairing interferon-γ (IFN-γ) secretion, proliferation, and cytolysis. CD28 modification abrogated interleukin-2 (IL-2) induction upon CAR engagement which in turn is no longer available to sustain Treg cell persistence. CARs with the modified CD28 endodomain thereby expedite the implementation of adoptive T-cell therapy in patients with a variety of cancer types that are heavily infiltrated by Treg cells.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD28 Antigens / genetics
  • CD28 Antigens / metabolism*
  • Immunohistochemistry
  • Immunotherapy, Adoptive
  • Interferon-gamma / genetics
  • Interferon-gamma / metabolism
  • Interleukin-2 / genetics
  • Interleukin-2 / metabolism*
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck) / metabolism*
  • Mice
  • Mice, Nude
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology*
  • Receptors, Antigen, T-Cell / metabolism*
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • T-Lymphocytes, Regulatory / immunology*
  • T-Lymphocytes, Regulatory / metabolism


  • CD28 Antigens
  • Interleukin-2
  • Receptors, Antigen, T-Cell
  • Recombinant Fusion Proteins
  • Interferon-gamma
  • Lymphocyte Specific Protein Tyrosine Kinase p56(lck)