IL-15, a novel T cell growth factor that shares activities and receptor components with IL-2.
Interleukin 15 is a newly discovered cytokine that shares biological activities with IL-2 and, like IL-2, is a member of the four-helix bundle cytokine family. We have shown that IL-15 shares components of the receptor for IL-2: the alpha chain of the IL-2R is not required, but both the beta and gamma chains are needed for IL-15 mediated bioactivities. A defect in IL-15 signaling may therefore contribute to the phenotype of X-linked severe combined immunodeficiency in humans, resulting from mutations in the common gamma chain. Differential ability of cells to bind and respond to IL-2 and IL-15 suggested the existence of an additional IL-15 specific receptor component. We identified an IL-15 specific binding protein (IL-15R alpha) on a murine T cell and isolated the corresponding cDNA. The IL-15R alpha is not a member of the hematopoietin receptor superfamily, but is structurally related to the alpha chain of the IL-2R. Differences in the expression pattern of IL-15 and its receptor compared to the IL-2 system suggest unique in vivo roles for IL-15.
Giri
J G
JG
Immunex Research and Development Corporation, Seattle, WA 98101, USA.
Anderson
D M
DM
Kumaki
S
S
Park
L S
LS
Grabstein
K H
KH
Cosman
D
D
D000818:Animals; D003001:Cloning, Molecular; D006801:Humans; D019409:Interleukin-15; D007376:Interleukin-2 / Q000502:physiology*; D007378:Interleukins / Q000502:physiology*; D008213:Lymphocyte Activation; D051379:Mice; D018123:Receptors, Interleukin / Q000502:physiology*; D015375:Receptors, Interleukin-2 / Q000737:chemistry; D013601:T-Lymphocytes / Q000166:cytology*
D019409:Interleukin-15; D007376:Interleukin-2; D007378:Interleukins; D018123:Receptors, Interleukin; D015375:Receptors, Interleukin-2