Interleukin 5 is a differentiation factor for cytotoxic T lymphocytes.
The role of IL-5 on the generation of cytotoxic T lymphocytes (CTL) was analysed using a culture system in which production of T helper cell factors was abrogated by exposure of the stimulator cells to ultraviolet irradiation. Supernatants from a T helper cell line (2.19 sup), recombinant (r) IL-2, rIL-4 and rIL-5 were then tested for the capacity to replace T cell help, on the generation of CTL. The results showed that the specific CTL response, in unseparated spleen cells, could be reconstituted by either 2.19 sup, IL-2 or IL-4. However, if the responder cells were purified in nylon wool, only 2.19 sup or rIL-4 plus rIL-5, but not each lymphokine per se, reconstituted the CTL response. Because IL-5 does not support T cell proliferation, it is suggested that IL-5 induces differentiation of immature precursors into CTL. Based on these findings and in an attempt to conciliate the conflicting views that have emerged from different reports, as to whether IL-2 by itself could support generation of CTL in purified T cells, a hypothesis is formulated, suggesting that T cell at different stages of differentiation require distinct lymphokines to acquire CTL effector function.
Ramos
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Unit for Applied Cell and Molecular Biology, University of Umeå, Sweden.
D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D002478:Cells, Cultured; D003601:Cytotoxicity Tests, Immunologic; D004247:DNA / Q000378:metabolism; D007376:Interleukin-2 / Q000502:physiology; D015847:Interleukin-4; D015848:Interleukin-5; D007378:Interleukins / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D011994:Recombinant Proteins; D013154:Spleen; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000528:radiation effects
D007376:Interleukin-2; D015848:Interleukin-5; D007378:Interleukins; D011994:Recombinant Proteins; D015847:Interleukin-4; D004247:DNA