Selective expansion of memory CD4(+) T cells by mitogenic human CD28 generates inflammatory cytokines and regulatory T cells

Eur J Immunol. 2008 Jun;38(6):1522-32. doi: 10.1002/eji.200737929.


Costimulatory signals are important for development of effector and regulatory T cells. In this case, CD28 signaling is usually considered inert in the absence of signaling through the TCR. By contrast, mitogenic rat CD28 mAb reportedly expand regulatory T cells without TCR stimulation. We found that a commercially available human CD28 mAb (ANC28) stimulated PBMC without TCR co-ligation or cross-linking; ANC28 selectively expanded CD4(+)CD25(+)FOXP3(-) (Teff) and CD4(+)CD25(+)FOXP3(+) (Treg) cells. ANC28 stimulated the CD45RO(+) CD4(+) (memory) population, whereas CD45RA(+)CD4(+) (naive) cells did not respond. ANC28 also induced inflammatory cytokines. Treg induced by ANC28 retain the Treg phenotype longer than costimulated Treg. Treg induced by ANC28 suppressed CD25(-) T cells through a contact-dependent mechanism. Purity influenced the response of CD4(+)CD25(+ )cells because bead-purified CD4(+)CD25(+ )cells (85-90% pure) responded strongly to ANC28, whereas 98% pure FACS-sorted CD4(+)CD25(bright) (Treg) did not respond. Purified CD4(+)CD25(int) cells responded similarly to the bead-purified CD4(+)CD25(+) cells. Thus, pre-activated CD4(+) T cells (CD25(int)) respond to ANC28 rather than Treg (CD25(bright)). The ability of ANC28 to expand both effectors producing inflammatory cytokines as well as suppressive regulatory T cells might be useful for ex vivo expansion of therapeutic T cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Androstadienes / pharmacology
  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / pharmacology*
  • CD28 Antigens / immunology*
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / immunology*
  • CD4-Positive T-Lymphocytes / metabolism
  • Cell Differentiation / drug effects
  • Cell Differentiation / immunology
  • Cell Proliferation / drug effects
  • Coculture Techniques
  • Cytokines / metabolism*
  • Enzyme Inhibitors / pharmacology
  • Forkhead Transcription Factors / analysis
  • Humans
  • Immunoglobulin Fab Fragments / immunology
  • Immunoglobulin Fab Fragments / pharmacology
  • Interleukin-2 Receptor alpha Subunit / analysis
  • Leukocyte Common Antigens / analysis
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / metabolism
  • Lymphocyte Activation / drug effects
  • Phosphodiesterase Inhibitors / pharmacology
  • Phosphoinositide-3 Kinase Inhibitors
  • Signal Transduction / drug effects
  • T-Lymphocyte Subsets / drug effects
  • T-Lymphocyte Subsets / immunology
  • T-Lymphocyte Subsets / metabolism
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism
  • T-Lymphocytes, Regulatory / cytology
  • T-Lymphocytes, Regulatory / drug effects
  • T-Lymphocytes, Regulatory / immunology*
  • Wortmannin


  • Androstadienes
  • Antibodies, Monoclonal
  • CD28 Antigens
  • Cytokines
  • Enzyme Inhibitors
  • FOXP3 protein, human
  • Forkhead Transcription Factors
  • Immunoglobulin Fab Fragments
  • Interleukin-2 Receptor alpha Subunit
  • Phosphodiesterase Inhibitors
  • Phosphoinositide-3 Kinase Inhibitors
  • Leukocyte Common Antigens
  • Wortmannin