Zhang J G, Hilton D J, Willson T A, McFarlane C, Roberts B A, Moritz R L, Simpson R J, Alexander W S, Metcalf D, Nicola N A
Walter and Eliza Hall Institute of Medical Research and the Cooperative Research Centre for Cellular Growth Factors, P.O. Royal Melbourne Hospital, Victoria 3050, Australia.
J Biol Chem. 1997 Apr 4;272(14):9474-80. doi: 10.1074/jbc.272.14.9474.
Interleukin-4 (IL-4) and interleukin-13 (IL-13) are structurally and functionally related cytokines which play an important role in the regulation of the immune response to infection. The functional similarity of IL-4 and IL-13 can be explained, at least in part, by the common components that form their cell surface receptors, namely the IL-4 receptor alpha-chain (IL-4Ralpha) and the IL-13 receptor alpha-chain (IL-13Ralpha). Soluble forms of the IL-4Ralpha have also been described and implicated in modulating the effect of IL-4. In this paper we describe the presence of a 45,000-50,000 Mr IL-13-binding protein (IL-13BP) in the serum and urine of mice. This protein binds IL-13 with a 100-300-fold higher affinity (KD = 20-90 pM) than does the cloned IL-13Ralpha (KD = 3-10 nM). In addition to this functional difference, the IL-13BP appears to be structurally and antigenically distinct from the IL-13Ralpha. Finally, unlike the cloned receptor, the IL-13BP acts as a potent inhibitor of IL-13 binding to its cell surface receptor, raising the possibility that it may be used to modulate the effects of IL-13 in vivo.
白细胞介素-4（IL-4）和白细胞介素-13（IL-13）是结构和功能相关的细胞因子，在调节对感染的免疫反应中起重要作用。IL-4和IL-13的功能相似性至少部分可以通过构成其细胞表面受体的共同成分来解释，即IL-4受体α链（IL-4Rα）和IL-13受体α链（IL-13Rα）。也已描述了IL-4Rα的可溶性形式，并认为其参与调节IL-4的作用。在本文中，我们描述了在小鼠血清和尿液中存在一种45,000 - 50,000道尔顿的IL-13结合蛋白（IL-13BP）。该蛋白与IL-13结合的亲和力（KD = 20 - 90 pM）比克隆的IL-13Rα（KD = 3 - 10 nM）高100 - 300倍。除了这种功能差异外，IL-13BP在结构和抗原性上似乎也与IL-13Rα不同。最后，与克隆的受体不同，IL-13BP可作为IL-13与其细胞表面受体结合的有效抑制剂，这增加了它可能用于在体内调节IL-13作用的可能性。
