Interfacing T-cell effector and regulatory function through CD137 (4-1BB) co-stimulation

Trends Immunol. 2005 Aug;26(8):440-6. doi: 10.1016/


Historically, co-stimulation has been regarded as a prerequisite for T-cell activation. A lack of co-stimulation results in peripheral T-cell tolerance, which manifests as unresponsiveness or death through apoptosis. Recent findings, however, suggest that eliciting co-stimulation can also induce tolerance. Reconciling these diametrically opposed results is certainly of academic importance but more importantly transcends basic immunology and impacts present and future clinical trials that are centered on modulating T-cell co-stimulation. This review will focus on CD137 (4-1BB) and propose a mechanism of action in which CD137-primed CD8 T cells express effector function and also inhibit CD4 T-cell activation. This model suggests that the same CD8 T cells possess antitumor effector function interfaced with regulatory capacity, which ultimately leads to concomitant inhibition of tumorigenesis and autoimmune disease.

Publication types

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

MeSH terms

  • Animals
  • Antigens, CD / immunology*
  • Antigens, CD / metabolism
  • Autoimmunity / immunology
  • Humans
  • Immune Tolerance / immunology
  • Receptors, Nerve Growth Factor / immunology*
  • Receptors, Nerve Growth Factor / metabolism
  • Receptors, Tumor Necrosis Factor / immunology*
  • Receptors, Tumor Necrosis Factor / metabolism
  • Review Literature as Topic
  • T-Lymphocytes / cytology
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • Tumor Necrosis Factor Receptor Superfamily, Member 9


  • Antigens, CD
  • Receptors, Nerve Growth Factor
  • Receptors, Tumor Necrosis Factor
  • TNFRSF9 protein, human
  • Tumor Necrosis Factor Receptor Superfamily, Member 9