Turk J L, Narayanan R B
Immunobiology. 1982 Apr;161(3-4):274-82. doi: 10.1016/S0171-2985(82)80083-1.
Epithelioid cells are cells of the mononuclear phagocyte system found in certain granulomas mainly associated with intense immunological activity. These cells show little phagocytic activity. In certain experimental granulomas such as those produced in guinea pigs sensitive to zirconium, and at sites of intense inflammatory reaction in man, they may contain varying amounts of rough endoplasmic reticulum ("secretory" epithelioid cells). In other situations such as tuberculoid leprosy and in some cases of sarcoidosis they may have the appearance of activated macrophages or take on a multivesicular appearance ("vesicular" epithelioid cells). It is suggested that "vesicular epithelioid cells could develop from "secretory" epithelioid cells by a process of degeneration. In studies comparing granulomas induced in lymph nodes draining the site of intradermal injection of mycobacteria, epithelioid cell granulomas were produced with BCG vaccine, whereas, the granulomas induced by Mycobacterium leprae contained undifferentiated macrophages that contained phagocytosed organisms. The BCG granulomas were in addition characterised by fibroblast infiltration, the presence of collagen and resolution by fibrosis. M. leprae granulomas showed little evidence of fibroblastic activity. Biochemical studies confirmed that BCG granulomas formed new collagen in vitro, whereas this did not take place with M. leprae granulomas. It is suggested that epithelioid cells could play an important role in fibrosis possibly by the secretion of a fibroblast activating factor.
上皮样细胞是单核吞噬细胞系统的细胞，存在于某些主要与强烈免疫活性相关的肉芽肿中。这些细胞几乎没有吞噬活性。在某些实验性肉芽肿中，如在对锆敏感的豚鼠中产生的肉芽肿，以及在人类强烈炎症反应部位，它们可能含有不同数量的粗面内质网（“分泌性”上皮样细胞）。在其他情况下，如结核样麻风病和某些结节病病例中，它们可能具有活化巨噬细胞的外观或呈现多囊泡外观（“泡状”上皮样细胞）。有人提出，“泡状上皮样细胞”可能是由“分泌性”上皮样细胞通过退化过程发展而来。在比较皮内注射分枝杆菌部位引流淋巴结中诱导的肉芽肿的研究中，卡介苗疫苗产生了上皮样细胞肉芽肿，而麻风分枝杆菌诱导的肉芽肿含有未分化的巨噬细胞，其中含有吞噬的生物体。卡介苗肉芽肿的另外特征是有成纤维细胞浸润、存在胶原蛋白并通过纤维化消退。麻风分枝杆菌肉芽肿几乎没有成纤维细胞活性的证据。生化研究证实，卡介苗肉芽肿在体外形成新的胶原蛋白，而麻风分枝杆菌肉芽肿则不会。有人提出上皮样细胞可能通过分泌成纤维细胞活化因子在纤维化中发挥重要作用。
