Lempertz U, Kühn U, Knop J, Becker D
Department of Dermatology, University of Mainz, Germany.
Int Arch Allergy Immunol. 1996 Sep;111(1):64-70. doi: 10.1159/000237347.
Endocytotic activation of epidermal Langerhans cells (LC) by immunogenic haptens is an early event during development of allergic contact dermatitis. In this work a fast and objective flow-cytometric assay for predictive in vitro testing of contact sensitizers by monitoring their influence on endocytotic mechanisms in murine LC was developed. Epidermal cell suspensions were labelled with a monoclonal antibody directed to MHC class II molecules and pH-sensitive fluorochrome-coupled second-step reagents. For untreated LC a significant quenching of fluorescence intensity by internalization of the MHC-antibody complexes into acidic compartments was noticed. Similar results were obtained in the presence of irritants, the lectin concanavalin A and the phorbol ester phorbol 12-myristate 13-acetate. In contrast stimulation with several well-defined sensitizing compounds resulted in partial conservation of the fluorescence intensity due to the internalization of the labelled complexes into less acidic compartments. Monitoring this modulation of endocytosis is an effective in vitro method to test for properties typical for moderate and strong contact sensitizers. It will help to assess the risk of unknown chemicals to act as haptens and should be useful for restriction of animal experimentation in this field.
免疫原性半抗原对表皮朗格汉斯细胞（LC）的内吞激活是过敏性接触性皮炎发生过程中的早期事件。在这项工作中，开发了一种快速且客观的流式细胞术检测方法，通过监测接触性致敏剂对小鼠LC内吞机制的影响，对其进行体外预测性检测。表皮细胞悬液用针对MHC II类分子的单克隆抗体和pH敏感荧光染料偶联的二抗进行标记。对于未处理的LC，可观察到MHC -抗体复合物内化到酸性区室导致荧光强度显著淬灭。在存在刺激物、凝集素伴刀豆球蛋白A和佛波酯佛波醇12 -肉豆蔻酸酯13 -乙酸酯的情况下也获得了类似结果。相比之下，用几种明确的致敏化合物刺激会导致荧光强度部分保留，这是由于标记复合物内化到酸性较弱的区室中。监测这种内吞作用的调节是一种有效的体外方法，可用于检测中度和强接触性致敏剂的典型特性。它将有助于评估未知化学物质作为半抗原的风险，并且应该有助于限制该领域的动物实验。
