Investigation of the immunocompetent cells that bind early pregnancy factor and preliminary studies of the early pregnancy factor target molecule
Investigation of the immunocompetent cells that bind early pregnancy factor and preliminary studies of the early pregnancy factor target molecule
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DOI：
10.1111/j.0818-9641.2004.01260.x
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发表时间：
2004-08
影响因子：
4
通讯作者：
S. Athanasas-Platsis;Maria J. Somodevilla-Torres;H. Morton;A. Cavanagh
中科院分区：
文献类型：
--
作者：
S. Athanasas-Platsis;Maria J. Somodevilla-Torres;H. Morton;A. Cavanagh
早孕因子（EPF）是一种具有免疫抑制和生长因子特性的分泌蛋白。它已被证明可以抑制小鼠的迟发型超敏反应以及大鼠和小鼠的急性和慢性实验性自身免疫性脑脊髓炎。在之前的研究中，我们已经证明 EPF 与淋巴细胞群结合，并且我们假设它通过与 CD4+ T 细胞结合来介导其抑制作用。在本研究中，我们分离了单核细胞和淋巴细胞亚群，并用荧光素 EPF 标记它们，以确定哪些群体结合 EPF。我们证明 EPF 特异性结合 CD4+、CD8+、CD14+（单核细胞）和 CD56+ NK 细胞，但不结合 CD19+ B 细胞。 EPF 靶向的细胞表面分子的身份尚不清楚，但由于 EPF 是细胞内蛋白伴侣蛋白 10 (Cpn10) 的细胞外同源物，我们研究了 EPF 受体是伴侣蛋白 60 (Cpn60) 膜相关形式的可能性，伴侣蛋白 60 是细胞内 Cpn10 的功能伙伴。通过外源碘化 Cpn10 与细胞的化学交联来可视化淋巴细胞上的 EPF 靶分子，并用抗 Cpn60 进行探测。还检查了抗 Cpn60 对 EPF 生物测定（玫瑰花结抑制试验）活性的影响。在这两种情况下，都没有观察到该抗体与推定受体的特异性相互作用。结论是EPF靶向的细胞表面分子不太可能是Cpn60的同源物。
Early pregnancy factor (EPF) is a secreted protein with immunosuppressive and growth factor properties. It has been shown to suppress the delayed‐type hypersensitivity response in mice as well as acute and chronic forms of experimental autoimmune encephalomyelitis in rats and mice, respectively. In previous studies, we have demonstrated that EPF binds to a population of lymphocytes and we hypothesized that it mediates its suppressive effects by binding to CD4+ T cells. In the present study, we isolated monocytes and subpopulations of lymphocytes and labelled them with fluoresceinated EPF in order to determine which populations bind EPF. We demonstrated that EPF binds specifically to CD4+, CD8+, CD14+ (monocytes) and CD56+ NK cells but not to CD19+ B cells. The identity of the molecule(s) on the cell surface that is targeted by EPF is unknown, but as EPF is an extracellular homologue of the intracellular protein chaperonin 10 (Cpn10), we examined the possibility that the EPF receptor is a membrane‐associated form of chaperonin 60 (Cpn60), the functional associate of Cpn10 within the cell. The EPF target molecule on lymphocytes was visualized by chemical cross‐linking of exogenous iodinated Cpn10 to cells and probed with anti‐Cpn60. The effect of anti‐Cpn60 on activity in the EPF bioassay, the rosette inhibition test, was also examined. In both instances, no specific interaction of this antibody and the putative receptor was observed. It was concluded that the cell surface molecule targeted by EPF is unlikely to be a homologue of Cpn60.