Stössel H, Koch F, Kämpgen E, Stöger P, Lenz A, Heufler C, Romani N, Schuler G
Department of Dermatology, University of Innsbruck, Austria.
J Exp Med. 1990 Nov 1;172(5):1471-82. doi: 10.1084/jem.172.5.1471.
Freshly isolated epidermal Langerhans cells (LC) can actively process native protein antigens, but are weak in sensitizing helper T cells. During culture, when LC mature into potent immunostimulatory dendritic cells, T cell sensitizing capacity develops but antigen processing capacity is downregulated. Processing of exogenous antigens for class II-restricted antigen presentation involves acidic organelles. We used the DAMP-technique to monitor acidic organelles at the ultrastructural level in fresh, as well as cultured, mouse and human LC. We observed that the loss of antigen processing capacity with culture of LC was reflected by the disappearance of certain acidic organelles, namely endosomes (particularly early ones), and the hitherto enigmatic LC granules ("Birbeck Granules"). Our findings support the notion that endosomes are critical for antigen processing and suggest that LC granules might be involved as well.
新鲜分离的表皮朗格汉斯细胞（LC）能够积极处理天然蛋白质抗原，但在致敏辅助性T细胞方面能力较弱。在培养过程中，当LC成熟为强效免疫刺激树突状细胞时，T细胞致敏能力会发展，但抗原处理能力会下调。将外源性抗原加工成II类限制性抗原呈递需要酸性细胞器参与。我们使用DAMP技术在超微结构水平监测新鲜的以及培养后的小鼠和人LC中的酸性细胞器。我们观察到，随着LC的培养，抗原处理能力的丧失表现为某些酸性细胞器的消失，即内体（特别是早期内体）以及迄今为止神秘的LC颗粒（“伯贝克颗粒”）的消失。我们的研究结果支持内体对抗原加工至关重要这一观点，并表明LC颗粒可能也参与其中。
