Ham Don-Il, Kim Stephen J, Chen Jun, Vistica Barbara P, Fariss Robert N, Lee Robert S, Wawrousek Eric F, Takase Hiroshi, Yu Cheng-Rong, Egwuagu Charles E, Chan Chi-Chao, Gery Igal
Laboratory of Immunology, National Eye Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Invest Ophthalmol Vis Sci. 2004 Mar;45(3):857-62. doi: 10.1167/iovs.03-1028.
Different conclusions have been reached in recent studies concerning the immune response or tolerance of transgenic (Tg) mice expressing foreign antigens under control of retinal antigen promoters. The present study was aimed at analyzing the state of tolerance in Tg mice expressing hen egg lysozyme (HEL) under control of the rhodopsin promoter.
Tg mice expressing HEL under control of the rhodopsin promoter (RhHEL-Tg) were generated and tested by conventional methods for immune responses against HEL. These Tg mice were also mated with Tg mice expressing HEL-specific receptor on their T lymphocytes and the double-Tg mice were examined for increased apoptosis in their thymi by the TUNEL assay, as well as for loss of HEL-specific T cells, by flow cytometry and proliferative response. The presence of HEL mRNA in mouse thymi was determined by RT-PCR.
RhHEL-Tg mice developed tolerance to HEL, shown by reduced cellular and humoral responses to HEL, as well as by the failure of ocular inflammation to develop after immunization with HEL. RhHEL-Tg mice expressed HEL mRNA in their thymus, and the tolerogenic mechanism in these mice was shown to be thymic deletion of HEL-specific T cells by the following observations in the double-Tg mice: (1) increased apoptosis in their thymi, (2) remarkable reduction in the proportion of the HEL-specific T cells, and (3) loss of lymphocyte response to low concentrations of HEL.
Tg mice expressing HEL under control of the rhodopsin promoter develop a tolerance for the foreign antigen, apparently as a result of thymic expression of HEL and deletion of T cells specific to this antigen.
在近期关于在视网膜抗原启动子控制下表达外源抗原的转基因（Tg）小鼠的免疫反应或耐受性的研究中得出了不同结论。本研究旨在分析在视紫红质启动子控制下表达鸡卵溶菌酶（HEL）的Tg小鼠的耐受状态。
构建在视紫红质启动子控制下表达HEL的Tg小鼠（RhHEL-Tg），并通过常规方法检测其对HEL的免疫反应。这些Tg小鼠还与在其T淋巴细胞上表达HEL特异性受体的Tg小鼠交配，通过TUNEL法检测双转基因小鼠胸腺中凋亡增加情况，通过流式细胞术和增殖反应检测HEL特异性T细胞的损失情况。通过RT-PCR测定小鼠胸腺中HEL mRNA的存在情况。
RhHEL-Tg小鼠对HEL产生耐受性，表现为对HEL的细胞和体液反应降低，以及在用HEL免疫后未发生眼部炎症。RhHEL-Tg小鼠在胸腺中表达HEL mRNA，双转基因小鼠的以下观察结果表明这些小鼠的致耐受机制是HEL特异性T细胞的胸腺缺失：（1）胸腺中凋亡增加；（Ⅱ）HEL特异性T细胞比例显著降低；（3）淋巴细胞对低浓度HEL的反应丧失。
在视紫红质启动子控制下表达HEL的Tg小鼠对外源抗原产生耐受性，显然是由于HEL在胸腺中的表达以及该抗原特异性T细胞的缺失。
