Addition of the CD28 signaling domain to chimeric T-cell receptors enhances chimeric T-cell resistance to T regulatory cells

Leukemia. 2006 Oct;20(10):1819-28. doi: 10.1038/sj.leu.2404366. Epub 2006 Aug 17.


T cells can be engineered to target tumor cells by transduction of tumor-specific chimeric receptors, consisting of an extracellular antigen-binding domain and an intracellular signaling domain. However, the peripheral blood of cancer patients frequently contains an increased number of T regulatory cells, which appear to inhibit immune reactivity. We have investigated the effects of T regulatory cells on chimeric T cells specific for the B-cell antigen CD19, as B-cell malignancies are attractive targets for chimeric T-cell therapy. When a CD19 single-chain Fv antibody was coupled to the CD3 zeta (zeta) chain, there was sharply reduced activity on exposure to T regulatory cells, measured by CD19+ target-induced proliferation and cytotoxicity. By contrast, expression in T cells of a chimeric receptor consisting of the intracellular portion of the CD28 molecule fused to the zeta-chain and CD19 single-chain Fv not only produced a higher proliferative response and an increased nuclear factor kappaB activation but also sustained these activities in the presence of T regulatory cells. These effects are seen whether the chimeric T cells are derived from normal donors or from patients with B-cell chronic lymphocytic leukemia, indicating the potential for clinical application in B cell malignancies.

Publication types

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

MeSH terms

  • Antigens, CD19 / genetics
  • CD28 Antigens / chemistry
  • CD28 Antigens / genetics*
  • CD3 Complex / genetics
  • Cell Division / immunology
  • Cytokines / metabolism
  • Flow Cytometry
  • Humans
  • Immunotherapy, Adoptive / methods*
  • K562 Cells
  • Leukemia, Lymphocytic, Chronic, B-Cell / immunology
  • Leukemia, Lymphocytic, Chronic, B-Cell / therapy*
  • Mutant Chimeric Proteins / chemistry
  • Mutant Chimeric Proteins / genetics
  • NF-kappa B / metabolism
  • Protein Structure, Tertiary
  • Receptors, Antigen, T-Cell / chemistry
  • Receptors, Antigen, T-Cell / genetics*
  • Signal Transduction / physiology
  • T-Lymphocytes, Cytotoxic / cytology
  • T-Lymphocytes, Cytotoxic / physiology*
  • T-Lymphocytes, Regulatory / cytology
  • T-Lymphocytes, Regulatory / physiology*
  • Transduction, Genetic


  • Antigens, CD19
  • CD28 Antigens
  • CD3 Complex
  • CD3 antigen, zeta chain
  • Cytokines
  • Mutant Chimeric Proteins
  • NF-kappa B
  • Receptors, Antigen, T-Cell