脲溶性牛黑素相关抗原的提取及其致葡萄膜炎活性的初步研究

目的 探讨眼葡萄膜组织中致葡萄膜炎性的自身抗原。方法 采用生化方法提取牛虹膜睫状体中脲溶性牛黑素相关抗原,对其进行凝胶电泳分析、检测氨基酸组成成分及含量;用脲溶性牛黑素相关抗原加佐剂对F344大鼠和Lewis大鼠进行免疫,诱发实验性脲溶性牛黑素相关抗原诱导的自身免疫性葡萄膜炎（experimental urea soluble farction of the bovine melanin-associated-antigen-induces uveitis,FMIU),并观察脲溶性牛黑素相关抗原的生物活性。结果 脲溶性牛黑素相关抗原相对分子质量约为64000,含有17种氨基酸,可诱发F344大鼠和Lewis大鼠的EMIU,炎性反应主要发生在前葡萄膜,严重者可伴发局灶性脉络膜炎,不伴有视网膜炎和松果体炎。结论 脲溶性牛黑素相关抗原可能是葡萄膜组织中致葡萄膜炎性活的主要自身抗原,其诱发的EMIU有别于视网膜可溶性抗原所诱导的实验性自身免疫性葡萄膜视网膜炎,不伴视网膜炎和松果体炎。

Urea soluble fraction of bovine melanin associated antigen and experimental study on its uveitogenic activity

OBJECTIVE: The purpose of this study was to investigate the uveitogenic activity of autoantigen in the bovine iris-ciliary body. METHODS: Urea soluble fraction of boveine melanin associated antigen (USF-BMAA) was isolated from the bovine iris-ciliary body biochemically and determined by SDS-PAGE as well as amino acid analysis. Lewis rats and F344 rats were immunized with USF-BMAA emulsified with equal volume complete Freud's adjuvant and Bordetella pertussis. RESULTS: A strongly stained protein band was observed in the USF-BMAA by SDS-PAGE whose molecular weight is approximate 64 000. Amino acid analysis of USF-BMAA showed that it contains 17 kinds of amino acids with high content of Glu, Leu and Asp. The experimental melanin associated antigen-induced uveitis (EMIU) was successfully incited in both eyes of the Lewis and F344 rats. The inflammation was mainly located in the anterior uvea, and spontaneously recovered. Mild focal choroiditis was present in the rats with severe lesion. However, the inflammation was not observed in the retina and pineal gland. CONCLUSIONS: USF-BMAA may be the major part of autoantigen of the uveal tract with uveitogenic activity. Unlike experimental autoimmune uveoretinitis (EAU) which is incited by the retinal soluble antigen (S-Ag) in the rats, no involvement of the retina and pineal gland is found in EMIU.