CYTOKINE EFFECTS OF CD23 ARE MEDIATED BY AN EPITOPE DISTINCT FROM THE IGE BINDING-SITE
CYTOKINE EFFECTS OF CD23 ARE MEDIATED BY AN EPITOPE DISTINCT FROM THE IGE BINDING-SITE
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DOI：
10.1002/j.1460-2075.1992.tb05531.x
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发表时间：
1992-12-01
期刊：
影响因子：
11.4
通讯作者：
SARFATI, M
中科院分区：
文献类型：
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作者：
MOSSALAYI, MD;AROCK, M;SARFATI, M
人 CD23 及其可溶形式 (sCD23) 除了具有 IgE 结合功能 (IgE/BF) 外，还表现出多种生物活性。 IgE 结合域最近被定位到 Cys163 和 Cys282 之间的残基，但其与 IgE 无关的 CD23 功能的参与仍然未知。为了阐明这一点，在CHO细胞中表达了一系列CD23或sCD23的N端、C端和内部缺失突变体，并测试了它们的能力（i）与IgE结合，（ii）诱导人骨髓前体细胞形成集落，（iii）促进早期前胸腺细胞表达成熟T细胞标志物，以及（iv）调节IgE合成。本研究表明细胞因子活性需要 Cys288 的存在，而该氨基酸对于 IgE/BF 来说不是必需的。使用各种构象敏感单克隆抗体的封闭实验进一步表明，细胞因子测定中 CD23 的活性表位与 IgE/BF 中涉及的活性表位不同。
Human CD23 and its soluble forms (sCD23) display various biological activities, in addition to their IgE binding function (IgE/BF). The IgE binding domain was recently mapped to residues between Cys163 and Cys282 but its involvement in IgE-independent, CD23 functions remains unknown. In order to clarify this point, a series of N-terminal, C-terminal and internal deletion mutants of CD23 or sCD23 were expressed in CHO cells and tested for their ability (i) to bind to IgE, (ii) to induce colony formation by human myeloid precursor cells, (iii) to promote mature T cell marker expression by early prothymocytes, and (iv) to regulate IgE synthesis. The present study indicates that cytokine activities require the presence of Cys288, while this amino acid is not necessary for IgE/BF. Blocking experiments using various conformation-sensitive monoclonal antibodies further suggest that active epitope(s) of CD23 in cytokine assays is(are) distinct from those involved in IgE/BF.