Rescue of human T cells by interleukin-9 (IL-9) from IL-2 deprivation-induced apoptosis: correlation with alpha subunit expression of the IL-9 receptor.
Interleukin-9 (IL-9) is a Th2-derived cytokine that uses the gamma-chain of the IL-2 receptor for signaling. Therefore, the responsiveness of human Th1 and Th2 cell clones to IL-9 was measured by examining the ability of this cytokine to prevent apoptosis induced by IL-2 deprivation. A time course study demonstrated that both subsets of T cell clones underwent apoptosis with similar kinetics when deprived of IL-2 and that viability could be maintained by the addition of either IL-4 or IL-7. Interestingly, IL-9 prevented apoptosis in only 2 (Th2) of 14 clones tested. Analysis of IL-9R alpha subunit expression on 18 T cell clones revealed that IL-9 responsiveness was directly proportional to the expression of the high-affinity receptor. IL-9 responsiveness was also dependent on long-term culturing because neither freshly isolated nor 3-day phytohemagglutinin (PHA)-stimulated peripheral blood lymphocytes (PBL) expressed IL-9R alpha. In summary, the data showed that IL-9 can rescue only a small subset of Th2 cells from apoptosis induced by growth factor withdrawal and that expression of IL-9R alpha is required for the antiapoptotic signals mediated by this cytokine.
Perdow-Hickman
S
S
Department of Microbiology and Immunology, Temple University School of Medicine, Philadelphia, PA 19140, USA.
Salgame
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P
D017209:Apoptosis / Q000187:drug effects* / Q000276:immunology; D002999:Clone Cells; D006801:Humans; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D015851:Interleukin-7 / Q000494:pharmacology; D016906:Interleukin-9 / Q000494:pharmacology*; D007700:Kinetics; D008213:Lymphocyte Activation; D021122:Protein Subunits; D018123:Receptors, Interleukin / Q000737:chemistry / Q000378:metabolism*; D053651:Receptors, Interleukin-9; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000276:immunology*; D018417:Th1 Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology; D018418:Th2 Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology
C508045:IL9R protein, human; D007376:Interleukin-2; D015851:Interleukin-7; D016906:Interleukin-9; D021122:Protein Subunits; D018123:Receptors, Interleukin; D053651:Receptors, Interleukin-9; D015847:Interleukin-4