Signal transduction through the human IL-2 receptor beta-chain expressed in IL-6-dependent mouse B cell hybridoma.
Non-covalent association between at least two polypeptides, alpha (p55) and beta (p70), yields a high-affinity interleukin 2 receptor (IL-2R). Recent findings suggest that the beta-chain can mediate IL-2 signals on its own, while the alpha-chain is not involved in IL-2 signal transduction. To study the role of the beta-chain, directly, we transfected with the human IL-2R beta-chain cDNA a murine IL-6-dependent B cell hybridoma, F12-28, which originally did not express IL-2R. We established a stable transformant, beta E12, expressing the beta-chain (Kd = 1300 pM, 3000 sites/cell) in the absence of any detectable alpha-chain. We showed that (i) beta E12 manifested the intermediate affinity IL-2 binding, which was completely blocked with anti-human beta-chain antibody (Mik-beta 1); (ii) beta E12 acquired an ability to proliferate in response to IL-2 (greater than 0.1 nM) in a dose-dependent manner. These results clearly demonstrate that the beta-chain itself is directly involved in IL-2 signal transduction in the absence of the alpha-chain. Our results also suggest that a certain IL-6-dependent B cell line possesses cellular components) capable of transducing IL-2 signals.
Tanaka
T
T
Department of Immunology, Tokyo Metropolitan Institute of Medical Science, Japan.
Tsudo
M
M
Karasuyama
H
H
Toyama
N
N
Hatakeyama
M
M
Taniguchi
T
T
Miyasaka
M
M
D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology; D004247:DNA / Q000235:genetics; D006801:Humans; D006825:Hybridomas / Q000276:immunology; D015850:Interleukin-6 / Q000494:pharmacology; D051379:Mice; D015375:Receptors, Interleukin-2 / Q000737:chemistry / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction / Q000276:immunology*; D014162:Transfection
D015850:Interleukin-6; D015375:Receptors, Interleukin-2; D004247:DNA