Napolitano M, Seamon K B, Leonard W J
Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development, Bethesda, Maryland 20892.
J Exp Med. 1990 Jul 1;172(1):285-9. doi: 10.1084/jem.172.1.285.
We have identified cell surface receptors for Act-2, a secreted protein expressed upon activation of T cells, B cells, and monocytes. Although 125I-Act-2 showed little, if any, specific binding to resting peripheral blood lymphocytes (PBL) receptors were readily detected on PHA/PMA-activated PBL and a variety of cell lines including MT-2, HL60, DMSO differentiated HL60, HeLa, and K562 cells. The equilibrium dissociation constant (Kd) is 3-12 nM for MT-2, K562, and PBL activated with PHA/PMA for 40-80 h. We have also identified a rabbit polyclonal antiserum that can block Act-2 binding to its receptors. The ability to detect specific Act-2 receptors and the development of a blocking antiserum should prove valuable in efforts to molecularly clone the Act-2 receptor and to dissect the biological actions of Act-2.
我们已经鉴定出Act-2的细胞表面受体，Act-2是一种在T细胞、B细胞和单核细胞激活后表达的分泌蛋白。尽管125I-Act-2与静息外周血淋巴细胞（PBL）几乎没有特异性结合（即便有也很少），但在PHA/PMA激活的PBL以及包括MT-2、HL60、经二甲基亚砜分化的HL60、HeLa和K562细胞在内的多种细胞系上很容易检测到受体。对于MT-2、K562以及用PHA/PMA激活40 - 80小时的PBL，平衡解离常数（Kd）为3 - 12 nM。我们还鉴定出一种兔多克隆抗血清，它能够阻断Act-2与其受体的结合。检测特异性Act-2受体的能力以及阻断抗血清的开发，在分子克隆Act-2受体和剖析Act-2的生物学作用的研究中应具有重要价值。
