TARGETED DISRUPTION OF THE MHC CLASS-II AA GENE IN C57BL/6 MICE
TARGETED DISRUPTION OF THE MHC CLASS-II AA GENE IN C57BL/6 MICE
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DOI：
10.1093/intimm/5.8.957
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发表时间：
1993-08-01
影响因子：
4.4
通讯作者：
BLUETHMANN, H
中科院分区：
文献类型：
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作者：
KONTGEN, F;SUSS, G;BLUETHMANN, H
通过在来自C57 BL/6小鼠的胚胎干（ES）细胞中靶向突变破坏MHC II类基因Aa以防止MHC II类分子的表达。与之前的报道相反，在C57 BL/6小鼠中研究了无效突变对T细胞发育的影响，这提供了明确的遗传背景。通过使用抗A（B）和抗Ia特异性单克隆抗体的细胞荧光分析，直接证明了B6-Aa 0/Aa 0纯合突变小鼠中完全缺乏MHC II类分子的细胞表面表达。胸腺中CD 4 + CD 8- T细胞的发育基本上不存在，除了少数表达高水平CD 4和低量CD 8的胸腺细胞。这些细胞中的大多数以高密度表达TCR。虽然在胸腺中未检测到成熟的CD 4 + CD 8- T细胞，但在淋巴结和脾脏中发现了一些具有CD 4 + CD 8-TCR（高）表型的T细胞。来自突变小鼠的外周T细胞可以在体外用丝裂原伴刀豆球蛋白A多克隆活化。然而，它们不能在自体淋巴细胞反应中被葡萄球菌肠毒素B刺激，从而证明这些小鼠中没有MHC II类表达。B6-Aa 0/Aa 0突变体中的外周B细胞是功能性的，并且通过产生与野生型细胞相似的抗原特异性IgM抗体来响应T细胞非依赖性抗原莱万。本研究中描述的B6-Aa 0/Aa 0突变小鼠代表了研究MHC II类分子参与淋巴细胞成熟和免疫应答的重要工具。
The MHC class II gene Aa was disrupted by targeted mutation in embryonic stem (ES) cells derived from C57BL/6 mice to prevent expression of MHC class II molecules. Contrary to previous reports, the effect of the null-mutation on T cell development was investigated in C57BL/6 mice, which provide a defined genetic background. The complete lack of cell surface expression of MHC class II molecules in B6-Aa0/Aa0 homozygous mutant mice was directly demonstrated by cytofluorometric analysis using anti-A(b) and anti-Ia specific mAbs. Development of CD4+CD8- T cells in the thymus was largely absent except for a small population of thymocytes expressing high levels of CD4 together with low amounts of CD8. The majority of these cells express the TCR at high density. Although mature CD4+CD8- T cells were undetectable in the thymus, some T cells with a CD4+CD8-TCR(high) phenotype were found in lymph nodes and spleen. Peripheral T cells from the mutant mice can be polyclonally activated in vitro with the mitogen concanavalin A. However, they could not be stimulated with staphylococcal enterotoxin B in autologous lymphocyte reactions, thereby demonstrating the absence of MHC class II expression in these mice. Peripheral B cells in B6-Aa0/Aa0 mutants were functional and responded to the T cell independent antigen levan by the production of antigen-specific IgM antibodies similar to wild-type cells. The B6-Aa0/Aa0 mutant mice described in this study represent an important tool to investigate the involvement of MHC class II molecules in lymphocyte maturation and the immune response.