Role of interleukin-7 in bone and T-cell homeostasis.
Initially defined as a B-cell growth factor, the pleiotropic nature of interleukin-7 (IL-7) has increasingly become appreciated. Besides its well-known roles in B- and T-cell lymphopoiesis, IL-7 is now known to regulate the homeostasis of both mature T cells and bone cells. In bone, the precise nature of how IL-7 affects osteoclasts and osteoblasts is controversial, since it has a variety of actions in different target cells. These activities are gender-specific and are dependent on whether IL-7 is delivered systemically or locally. In mature T cells, IL-7 is essential for the survival of nearly all subsets. Naïve T cells are also dependent on IL-7 for survival and homeostatic proliferation in response to lymphopenia. In addition, IL-7 plays a role in the survival of memory CD8+ cells, and at high concentrations, it can compensate for the absence of IL-15. The role of IL-7 on memory CD4+ cells remains controversial and has yet to be firmly established.
Lee
Sun-Kyeong
SK
University of Connecticut Health Center, Farmington, CT 0630-1850, USA. slee@neuron.uchc.edu
Surh
Charles D
CD
D000818:Animals; D001402:B-Lymphocytes / Q000502:physiology; D001842:Bone and Bones / Q000502:physiology*; D002470:Cell Survival; D006706:Homeostasis; D006801:Humans; D007156:Immunologic Memory; D015851:Interleukin-7 / Q000502:physiology*; D008213:Lymphocyte Activation; D010010:Osteoclasts / Q000502:physiology; D010012:Osteogenesis; D013601:T-Lymphocytes / Q000502:physiology*
D015851:Interleukin-7