CLASS-II-RESTRICTED IGG2AB-SPECIFIC T-CELLS RECOGNIZE A SIGNAL-MINUS FORM OF THE V-CH3B ANTIGEN
CLASS-II-RESTRICTED IGG2AB-SPECIFIC T-CELLS RECOGNIZE A SIGNAL-MINUS FORM OF THE V-CH3B ANTIGEN
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DOI：
10.1002/eji.1830210613
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发表时间：
1991-06-01
影响因子：
5.4
通讯作者：
BIKOFF, EK
中科院分区：
文献类型：
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作者：
BIKOFF, EK
为了研究自我肽何时何地与主要组织相容性复合物II类分子相关以诱导耐受性的问题，我们最近开发了一种系统，其中可以使用基因克隆技术操纵抗原表达的细胞内位点。 我们先前构建了截短的IgG 2a基因，其包含来自IgG 2a（B）重（H）链的可变（V）结构域和C（H）3结构域（不包括膜外显子）。 在Ia+ B淋巴瘤细胞中，在IG H链增强子的控制下，分泌形式的V-CH 3b蛋白以高水平表达，并被II类限制性IgG 2a（B）特异性T细胞杂交体有效识别。 在这里，我们描述了一种修饰的V-CH 3b基因构建体，其中编码信号肽的序列被删除。 一个强有力的论据可以作出的信号较少的V-CH 3b蛋白主要是在胞质溶胶中表达。 我们表明，表达无信号形式的V-CH 3 B蛋白的转染L细胞系可以刺激II类限制性IgG 2a（B）特异性T细胞。 细胞混合实验表明，这种反应不可能是由于被动摄取的可溶性抗原肽释放到培养上清液。 这些实验表明，没有明显的手段到达细胞表面的细胞质蛋白质可以被呈递给II类限制性T细胞。
To study the question when and where self peptides become associated with major histocompatibility complex class II molecules for tolerance induction, we recently developed a system in which the intracellular site(s) of antigen expression could be manipulated using gene cloning techniques. We previously constructed a truncated IgG2a gene comprising a variable (V) domain and the C(H)3 domain (not including the membrane exons) from the IgG2a(b) heavy (H) chain. The secreted form of the V-CH3b protein was expressed at high levels under control of the Ig H chain enhancer in Ia+ B lymphoma cells and was efficiently recognized by class II-restricted IgG2a(b)-specific T cell hybrids. Here we describe a modified V-CH3b gene construct in which the sequences encoding the signal peptide were deleted. A strong argument can be made that the signal-less V-CH3b protein is predominantly expressed in the cytosol. We show that transfected L cell lines expressing the signal-less form of the V-CH3b protein can stimulate class II-restricted IgG2a(b)-specific T cells. Cell mixing experiments indicate that this response cannot be due to passive uptake of soluble antigenic peptides released into culture supernatants. These experiments demonstrate that a cytoplasmic protein having no obvious means of reaching the cell surface can be presented to class II-restricted T cells.