Internalization of interleukin 1 (IL 1) correlates with IL 1-induced IL 2 receptor expression and IL 2 secretion of EL4 thymoma cells.
The cytokine interleukin 1 (IL 1) plays an important role in the induction of IL 2 secretion and high-affinity IL 2 receptor (IL 2R) expression by T cells. The events that follow binding of IL 1 to IL 1R, however, are still unknown. In this study we describe two variants of the murine thymoma EL4 (5D3 and D6/76) that express comparable numbers of cell surface IL 1 receptors and bind IL 1 with the same affinity, but show distinct IL 1-dependent IL 2 secretion and IL 2R expression. In the presence of the tumor promoter phorbol 12-myristate 13-acetate IL 1 augments IL 2 secretion and IL 2R expression of EL4 5D3 but not of EL4 D6/76 cells. Comparison of the internalization of IL 1 by both clones revealed that EL4 D6/76 was unable to transport cell surface-bound IL 1 to the cytoplasm. These findings suggest that internalization of receptor-bound IL 1 is required for the action of this cytokine.
Von Hoegen
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I
Institute for Immunology and Genetics, German Cancer Research Center, Heidelberg.
Falk
W
W
Kojouharoff
G
G
Krammer
P H
PH
D000818:Animals; D002460:Cell Line; D002999:Clone Cells / Q000378:metabolism; D003432:Cross-Linking Reagents; D007375:Interleukin-1 / Q000378:metabolism* / Q000502:physiology; D007376:Interleukin-2 / Q000096:biosynthesis* / Q000378:metabolism; D007457:Iodine Radioisotopes; D051379:Mice; D012333:RNA, Messenger / Q000096:biosynthesis; D011971:Receptors, Immunologic / Q000032:analysis; D017472:Receptors, Interleukin-1; D015375:Receptors, Interleukin-2 / Q000096:biosynthesis*; D013945:Thymoma / Q000276:immunology / Q000378:metabolism*; D013953:Thymus Neoplasms / Q000276:immunology / Q000378:metabolism*
D003432:Cross-Linking Reagents; D007375:Interleukin-1; D007376:Interleukin-2; D007457:Iodine Radioisotopes; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D017472:Receptors, Interleukin-1; D015375:Receptors, Interleukin-2