Hioe C E, Frelinger J A
Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599, USA.
Mol Immunol. 1995 Jul;32(10):725-31. doi: 10.1016/0161-5890(95)00040-l.
We have investigated mutation of a dominant cytotoxic T cell (CTL) epitope from the nucleoprotein (NP) of lymphocytic choriomeningitis virus (LCMV). Five NP peptide analogs with single substitutions at the predicted anchor residues (designated by the wild type amino acid, the position number and the new amino acid: P2A, P2R, M9L and M9K) and at a non-anchor position (S5N) were examined for binding to class I, H-2 Ld molecules. Each of the substitutions decreased or abolished the capacity of the NP peptide to increase cell surface Ld expression and to induce Ld stabilization in the cell lysates, indicating that these substitutions significantly affected peptide binding to Ld. We tested the peptide analogs for recognition by bulk primary CTL specific for LCMV, and for their ability to stimulate in vitro the CTL originally induced by wild type LCMV. Except for the M9L change, all mutations reduced CTL recognition by at least 100-fold, and the analogs failed to stimulate the CTL in vitro. The M9L peptide was recognized by the CTL and stimulated CTL in vitro almost as well as wild type; however, this peptide induced Ld stabilization in the cell lysates to a much lesser extent than wild type. Overall, this study demonstrates that mutations in the NP epitope affected peptide binding to the Ld molecule and CTL recognition.
我们研究了淋巴细胞性脉络丛脑膜炎病毒（LCMV）核蛋白（NP）中一个显性细胞毒性T细胞（CTL）表位的突变情况。检测了五个NP肽类似物，它们在预测的锚定残基处有单个替换（由野生型氨基酸、位置编号和新氨基酸指定：P2A、P2R、M9L和M9K）以及在一个非锚定位置（S5N），检测其与I类H-2 Ld分子的结合情况。每个替换都降低或消除了NP肽增加细胞表面Ld表达以及在细胞裂解物中诱导Ld稳定的能力，这表明这些替换显著影响了肽与Ld的结合。我们测试了这些肽类似物被针对LCMV的大量初级CTL识别的情况，以及它们在体外刺激最初由野生型LCMV诱导的CTL的能力。除了M9L变化外，所有突变至少使CTL识别降低了100倍，并且这些类似物在体外未能刺激CTL。M9L肽能被CTL识别，并且在体外刺激CTL的效果几乎与野生型一样好；然而，该肽在细胞裂解物中诱导Ld稳定的程度比野生型小得多。总体而言，这项研究表明NP表位中的突变影响了肽与Ld分子的结合以及CTL识别。
