Mahoney M G, Aho S, Uitto J, Stanley J R
Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
J Invest Dermatol. 1998 Aug;111(2):308-13. doi: 10.1046/j.1523-1747.1998.00279.x.
Sera of patients with paraneoplastic pemphigus (PNP) characteristically immunoprecipitate five proteins, observations confirmed with the sera examined in this study. The proteins characterized thus far as autoantigens in PNP all belong to the plakin family of proteins and include desmoplakin, the 230 kDa bullous pemphigoid antigen, and envoplakin. The pattern of bands precipitated from metabolically labeled human keratinocyte extracts by each PNP serum was different, suggesting varying titers of antibodies against unique epitopes in various plakin family members. To further characterize this PNP antibody response, we produced fusion proteins of the homologous tail region of five plakin family members, including the recently cloned periplakin. Immunoblotting of equal amounts of each plakin tail-glutathione S-transferase fusion protein with PNP sera revealed a strong reaction with the envoplakin tail domain. Each sera also recognized periplakin, and certain sera recognized desmoplakin and plectin, and, weakly, bullous pemphigoid antigen 1. PNP sera were affinity purified with periplakin and envoplakin tail fusion proteins. Immunoprecipitation and immunoblotting with these affinity purified antibodies revealed shared as well as unique epitopes in the tail domains of these plakins. This study indicates that a homologous region in the carboxy-terminus of plakins, including the newly characterized periplakin, serves as an antigenic site in PNP.
副肿瘤性天疱疮（PNP）患者的血清典型地能免疫沉淀出五种蛋白质，本研究中检测的血清证实了这一观察结果。迄今为止在PNP中被鉴定为自身抗原的蛋白质均属于plakin蛋白家族，包括桥粒斑蛋白、230 kDa大疱性类天疱疮抗原和内披蛋白。每种PNP血清从经代谢标记的人角质形成细胞提取物中沉淀出的条带模式各不相同，这表明针对各种plakin家族成员中独特表位的抗体滴度各异。为了进一步表征这种PNP抗体反应，我们制备了五种plakin家族成员同源尾部区域的融合蛋白，包括最近克隆的周膜蛋白。用PNP血清对等量的每种plakin尾部 - 谷胱甘肽S - 转移酶融合蛋白进行免疫印迹分析，结果显示与内披蛋白尾部结构域有强烈反应。每种血清也识别周膜蛋白，某些血清识别桥粒斑蛋白和网蛋白，并且对大疱性类天疱疮抗原1的识别较弱。用周膜蛋白和内披蛋白尾部融合蛋白对PNP血清进行亲和纯化。用这些亲和纯化的抗体进行免疫沉淀和免疫印迹分析，揭示了这些plakin尾部结构域中存在共同以及独特的表位。本研究表明，包括新鉴定的周膜蛋白在内的plakin羧基末端的同源区域在PNP中作为抗原位点。
