Hussey R E, Richardson N E, Kowalski M, Brown N R, Chang H C, Siliciano R F, Dorfman T, Walker B, Sodroski J, Reinherz E L
Laboratories of Immunobiology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115.
Nature. 1988 Jan 7;331(6151):78-81. doi: 10.1038/331078a0.
The CD4 (T4) molecule is expressed on a subset of T lymphocytes involved in class II MHC recognition, and is probably the physiological receptor for one or more monomorphic regions of class II MHC (refs 1-3). CD4 also functions as a receptor for the human immunodeficiency virus (HIV) exterior envelope glycoprotein (gp120) (refs 4-9), being essential for virus entry into the host cell and for membrane fusion, which contributes to cell-to-cell transmission of the virus and to its cytopathic effects. We have used a baculovirus expression system to generate mg quantities of a hydrophilic extracellular segment of CD4. Concentrations of soluble CD4 in the nanomolar range, like certain anti-CD4 monoclonal antibodies, inhibit syncytium formation and HIV infection by binding gp120-expressing cells. Perhaps more importantly, class II specific T-cell interactions are uninhibited by soluble CD4 protein, whereas they are virtually abrogated by equivalent amounts of anti-T4 antibody. This may reflect substantial differences in CD4 affinity for gp120 and class II MHC.
CD4（T4）分子在参与II类主要组织相容性复合体（MHC）识别的一部分T淋巴细胞上表达，并且可能是II类MHC一个或多个单态区域的生理受体（参考文献1 - 3）。CD4还作为人类免疫缺陷病毒（HIV）外膜糖蛋白（gp120）的受体发挥作用（参考文献4 - 9），这对于病毒进入宿主细胞和膜融合至关重要，而膜融合有助于病毒的细胞间传播及其细胞病变效应。我们利用杆状病毒表达系统制备了毫克量的CD4亲水性细胞外片段。纳摩尔浓度范围的可溶性CD4，如同某些抗CD4单克隆抗体一样，通过结合表达gp120的细胞来抑制合胞体形成和HIV感染。也许更重要的是，可溶性CD4蛋白不会抑制II类特异性T细胞相互作用，而等量的抗T4抗体实际上会消除这种相互作用。这可能反映出CD4对gp120和II类MHC的亲和力存在显著差异。
