IL-7 and IL-15: biology and roles in T-Cell immunity in health and disease

Crit Rev Immunol. 2008;28(4):325-39. doi: 10.1615/critrevimmunol.v28.i4.40.

Abstract

Cytokines IL-7 and IL-15 are essentially involved in T-cell homeostasis. IL-7 is required for developing mature T cells in the thymus, whereas in the periphery, it promotes the survival of naïve and memory T cells by upregulating the antiapoptotic molecule Bcl-2. IL-15 potently induces the proliferation of memory CD8+ T cells independently of antigen and augments their effector function. Although IL-7 and IL-15 may help to defend the host against microorganisms and tumors by promoting T-cell immunity, dysregulated production of IL-7 and IL-15 can be harmful. In fact, increased levels of IL-15 in the circulation and inflamed tissues have been reported in various autoimmune diseases, including rheumatoid arthritis (RA), possibly contributing to the pathogenesis. In addition, IL-7, which may induce the production of inflammatory cytokines from T cells and monocytes, are found to be elevated in the joints of patients with RA. Here, we review what is currently known about the roles of these cytokines in T-cell immunity, in general, as well as in RA, in particular, focusing on recent discoveries.

Publication types

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

MeSH terms

  • Animals
  • Arthritis, Rheumatoid / etiology
  • Arthritis, Rheumatoid / immunology
  • Humans
  • Interleukin-15 / immunology*
  • Interleukin-7 / immunology*
  • Receptors, Interleukin-15 / physiology
  • Receptors, Interleukin-7 / physiology
  • T-Lymphocytes / immunology*

Substances

  • Interleukin-15
  • Interleukin-7
  • Receptors, Interleukin-15
  • Receptors, Interleukin-7