Brown M H, Boles K, van der Merwe P A, Kumar V, Mathew P A, Barclay A N
Medical Research Council Cellular Immunology Unit, Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom.
J Exp Med. 1998 Dec 7;188(11):2083-90. doi: 10.1084/jem.188.11.2083.
2B4 is a cell surface glycoprotein related to CD2 and implicated in the regulation of natural killer and T lymphocyte function. A recombinant protein containing the extracellular region of mouse (m)2B4 attached to avidin-coated fluorescent beads bound to rodent cells, and binding was completely blocked by CD48 monoclonal antibodies (mAbs). Using surface plasmon resonance, we showed that purified soluble mCD48 bound m2B4 with a six- to ninefold higher affinity (Kd approximately 16 microM at 37 degreesC) than its other ligand, CD2. Human CD48 bound human 2B4 with a similar affinity (Kd approximately 8 microM). The finding of an additional ligand for CD48 provides an explanation for distinct functional effects observed on perturbing CD2 and CD48 with mAbs or by genetic manipulation.
2B4是一种与CD2相关的细胞表面糖蛋白，参与自然杀伤细胞和T淋巴细胞功能的调节。一种重组蛋白，其包含与抗生物素蛋白包被的荧光珠相连的小鼠（m）2B4细胞外区域，该荧光珠与啮齿动物细胞结合，且结合作用被CD48单克隆抗体（mAb）完全阻断。利用表面等离子体共振技术，我们发现纯化的可溶性mCD48与m2B4结合的亲和力比其另一个配体CD2高6至9倍（37℃时Kd约为16μM）。人CD48与人2B4以相似的亲和力结合（Kd约为8μM）。发现CD48的另一种配体为用单克隆抗体或通过基因操作干扰CD2和CD48时观察到的不同功能效应提供了解释。
