Site of nonrestrictive binding of SEA to class II MHC antigens.
Site of nonrestrictive binding of SEA to class II MHC antigens.
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SEA 与 II 类 MHC 抗原的非限制性结合位点。
DOI：
10.1159/000235288
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Johnson,HM
中科院分区：
文献类型：
--
作者：
Pontzer,CH;Russell,JK;Jarpe,MA;Johnson,HM
我们使用合成肽方法表明，葡萄球菌肠毒素 A (SEA) 的 N 端 45 个氨基酸（SEA(1–45)）构成其在 II 类主要组织相容性复合体 (MHC) 分子上结合位点的重要部分。通过流式细胞术评估，SEA(1-45) 和较小程度的 SEA(1-27) 能够在 Raji 细胞上取代 HLA-DR 中的 SEA，并在直接结合测定中与放射性标记的 SEA 竞争与 HLA-DR 的相互作用。 SEA与鼠A-20细胞上的la的特异性结合可以被相同的肽抑制[即。 SEA(1–45) > SEA(1–27)] 阻断与 HLA-DR 的结合。因此，不同的 II 类 MHC 分子与 SEA 上的相同功能位点相关。此外，使用 ELISA 系统证明 SEA(1–45) 能够直接结合小鼠合成的 I-Aβbp 肽 I-Aβb(65–85)，该肽包含参与 SEA 呈递给 T 细胞的 II 类 MHC 分子的结合位点。因此，我们在SEA上定位了一个参与与II类MHC抗原选择性表面缔合的位点，并鉴定了该位点结合的II类MHC抗原上的区域。
We have used the synthetic peptide approach to show that the N-terminal 45-amino acids of staphylococcal enterotoxin A (SEA), SEA(1–45), constitute an important part of its binding site on class II major histocompatibility complex (MHC) molecules. SEA(1–45) and to a lesser extent SEA(1–27) were able to displace SEA from HLA-DR on Raji cells as assessed by flow cytometry and to compete with radiolabeled SEA for interaction with HLA-DR in a direct binding assay. Specific binding of SEA to la on murine A-20 cells could be inhibited by the same peptides [i.e. SEA(1–45) > SEA(1–27)] that blocked binding to HLA-DR. Therefore, different class II MHC molecules associate with the same functional site on SEA. Further, an ELISA system was used to demonstrate that SEA(1–45) is able to directly bind to a mouse synthetic I-Aβbpeptide, I-Aβb(65–85), which contains a binding site of the class II MHC molecule involved in SEA presentation to T cells. Thus, we have localized a site on SEA that is involved in selective surface association with class II MHC antigens and identified the region on the class II MHC antigen to which that site binds.