Egawa M, Maeno M, Kung H F, Schwabe M
Laboratory of Biochemical Physiology, National Cancer Institute-Frederick Cancer Research and Development Center, Maryland, USA.
Cytokine. 1995 Jan;7(1):83-8. doi: 10.1006/cyto.1995.1011.
We investigated the biochemical properties of the 80 kDa binding subunit (gp80) of the human interleukin 6 receptor (IL-6R) in the genetic environment of the amphibian Xenopus laevis. In vitro transcribed mRNA encoding full length human gp80 was microinjected into Xenopus laevis stage VI oocytes. Protein expression was monitored by iodinated IL-6 and human gp80-specific monoclonal antibodies (mAb) PM1 and MT18. Maximal IL-6 binding activity was observed between 36-42 h after injection. Scatchard analysis indicated that gp80-injected oocytes expressed two independent classes of IL-6 binding sites of high- (Kd1 = 9 x 10(-11) M, 20 x 10(6) sites/cell) and low-affinity (Kd2 = 2 x 10(-9) M, 70.3 x 10(6) sites/cell). PM1 but not MT18 completely inhibited IL-6 binding to injected eggs. Our data suggest that the human IL-6R alpha-subunit gp80 is sufficient to confer high- and low-affinity IL-6 binding to Xenopus laevis oocytes.
我们在非洲爪蟾的遗传环境中研究了人白细胞介素6受体（IL-6R）80 kDa结合亚基（gp80）的生化特性。将编码全长人gp80的体外转录mRNA显微注射到非洲爪蟾VI期卵母细胞中。通过碘化IL-6和人gp80特异性单克隆抗体（mAb）PM1和MT18监测蛋白质表达。注射后36 - 42小时观察到最大IL-6结合活性。Scatchard分析表明，注射gp80的卵母细胞表达两类独立的IL-6结合位点，即高亲和力（Kd1 = 9×10⁻¹¹ M，20×10⁶个位点/细胞）和低亲和力（Kd2 = 2×10⁻⁹ M，70.3×10⁶个位点/细胞）。PM1而非MT18完全抑制IL-6与注射卵的结合。我们的数据表明，人IL-6Rα亚基gp80足以赋予非洲爪蟾卵母细胞高亲和力和低亲和力的IL-6结合能力。
