CTLA-4-Fas ligand functions as a trans signal converter protein in bridging antigen-presenting cells and T cells
CTLA-4-Fas ligand functions as a trans signal converter protein in bridging antigen-presenting cells and T cells
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DOI：
10.1093/intimm/13.4.529
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发表时间：
2001-04-01
影响因子：
4.4
通讯作者：
Tykocinski, ML
中科院分区：
文献类型：
--
作者：
Huang, JH;Tykocinski, ML
共刺激物阻断和反式抑制信号，分别使用CTLA-4-Ig和Fas配体(FasL)作为抑制致病T细胞的替代策略。这项研究描述了一种新的异质双功能融合蛋白CTLA-4-FasL，它被设计成在单个蛋白中结合共刺激因子阻断和反式抑制信号转导。用CTLA-4和Fast的胞外区编码序列框内连接的嵌合表达盒生产CTLA-4-FasL融合蛋白。免疫荧光和流式细胞术证实CTLA-4-FasL可与表达B7-1/B7-2的Daudi B细胞和表达Fas的Jurkat T细胞结合。Daudi和其他B7-1/B7-2(+)B细胞株的加入可显著增强CTLA-4-FasL诱导Jurkat靶细胞凋亡的能力，为可溶性CTLA-4-融合蛋白提供了膜平台。此外，在双室实验中，预包被CTLA-4-FasL的Daudi细胞表现出细胞接触依赖性的Jurkat抑制活性。值得注意的是，当用于抑制外周血单核细胞的体外细胞增殖时，CTLA-4-FasL的效力类似于广泛鉴定的CTLA-4-Ig融合蛋白的1000倍。此外，CTLA-4-FasL诱导的抑制程度明显超过CTLA-4-Ig和可溶性Fast联合使用时的抑制程度。CTLA-4-FasL代表了一类新的融合蛋白中的第一种，在这里被命名为‘反式信号转换蛋白’，它结合了反式信号掩蔽和直接反式信号功能。
Co-stimulator blockade and trans inhibitory signaling, using agents such as CTLA-4-Ig and Fas ligand (FasL) respectively have been invoked as alternative strategies for suppressing pathogenic T cells. This study describes a novel hetero-bifunctional fusion protein, CTLA-4-FasL, designed to combine within a single protein both co-stimulator blocking and trans inhibitory signaling potentials. A chimeric expression cassette, in which the ectodomain coding sequences for CTLA-4 and Fast were linked in-frame, was used to produce a CTLA-4-FasL fusion protein. CTLA-4-FasL binding to both B7-1/B7-2-expressing Daudi B cells and Fas-expressing Jurkat T cells was documented by immunofluorescence and flow cytometry, The capacity of CTLA-4-FasL to induce apoptosis in Jurkat targets was markedly enhanced by the addition of Daudi and other B7-1/B7-2(+) B cell lines, which provided a membrane platform for the otherwise soluble CTLA-4-fusion protein. Moreover, in dual-chamber experiments, Daudi cells pre-coated with CTLA-4-FasL demonstrated Jurkat inhibitory activity that was cell-contact dependent. Significantly, when used to inhibit In vitro cellular proliferation of peripheral blood mononuclear cells, CTLA-4-FasL was similar to 1000-fold more potent than the extensively characterized CTLA-4-Ig fusion protein. Furthermore, the degree of inhibition induced by CTLA-4-FasL substantially surpassed that observed for CTLA-4-Ig and a soluble Fast when used in combination. CTLA-4-FasL represents the first of a novel class of fusion proteins, designated here as 'trans signal converter proteins', that combine trans signal masking and direct trans signaling functions.