Sigurdson Christina J, Barillas-Mury Carolina, Miller Michael W, Oesch Bruno, van Keulen Lucien J M, Langeveld Jan P M, Hoover Edward A
Department of Microbiology, Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Fort Collins, CO 80523-1671, USA1.
Colorado Division of Wildlife, Wildlife Research Center, 317 West Prospect Road, Fort Collins, CO 80526-2097, USA2.
J Gen Virol. 2002 Oct;83(Pt 10):2617-2628. doi: 10.1099/0022-1317-83-10-2617.
Up to 15% of free-ranging mule deer in northeastern Colorado and southeastern Wyoming, USA, are afflicted with a prion disease, or transmissible spongiform encephalopathy (TSE), known as chronic wasting disease (CWD). CWD is similar to a subset of TSEs including scrapie and variant Creutzfeldt-Jakob disease in which the abnormal prion protein isoform, PrP(CWD), accumulates in lymphoid tissue. Experimental scrapie studies have indicated that this early lymphoid phase is an important constituent of prion replication interposed between mucosal entry and central nervous system accumulation. To identify the lymphoid target cells associated with PrP(CWD), we used triple-label immunofluorescence and high-resolution confocal microscopy on tonsils from naturally infected deer in advanced disease. We detected PrP(CWD) primarily extracellularly in association with follicular dendritic and B cell membranes as determined by frequent co-localization with antibodies against membrane bound immunoglobulin and CD21. There was minimal co-localization with cytoplasmic labels for follicular dendritic cells (FDC). This finding could indicate FDC capture of PrP(CWD), potentially in association with immunoglobulin or complement, or PrP(C) conversion on FDC. In addition, scattered tingible body macrophages in the germinal centre contained coarse intracytoplasmic aggregates of PrP(CWD), reflecting either phagocytosis of PrP(CWD) on FDC processes, apoptotic FDC or B cells, or actual PrP(CWD) replication within tingible body macrophages. To compare lymphoid cell targets in early and advanced disease, we also examined: (i) PrP(CWD) distribution in lymphoid cells of fawns within 3 months of oral CWD exposure and (ii) tonsil biopsies from preclinical deer with naturally acquired CWD. These studies revealed that the early lymphoid cellular distribution of PrP(CWD) was similar to that in advanced disease, i.e. in a pattern suggesting FDC association. We conclude that in deer, PrP(CWD) accumulates primarily extracellularly and associated with FDCs and possibly B cells - a finding which raises questions as to the cells responsible for pathological prion production.
在美国科罗拉多州东北部和怀俄明州东南部，高达15%的野生骡鹿感染了一种朊病毒疾病，即传染性海绵状脑病（TSE），称为慢性消耗病（CWD）。CWD类似于TSE的一个子集，包括羊瘙痒病和变异型克雅氏病，其中异常的朊病毒蛋白异构体PrP（CWD）在淋巴组织中积累。实验性羊瘙痒病研究表明，这个早期淋巴阶段是朊病毒复制的一个重要组成部分，介于黏膜进入和中枢神经系统积累之间。为了确定与PrP（CWD）相关的淋巴靶细胞，我们对晚期疾病自然感染鹿的扁桃体进行了三重标记免疫荧光和高分辨率共聚焦显微镜检查。我们检测到PrP（CWD）主要位于细胞外，与滤泡树突状细胞和B细胞膜相关，这是通过与抗膜结合免疫球蛋白和CD21抗体的频繁共定位确定的。与滤泡树突状细胞（FDC）的细胞质标记物的共定位很少。这一发现可能表明FDC捕获了PrP（CWD），可能与免疫球蛋白或补体有关，或者是FDC上的PrP（C）转化。此外，生发中心散在的吞噬细胞含有粗大的细胞质内PrP（CWD）聚集体，这反映了FDC过程、凋亡的FDC或B细胞对PrP（CWD）的吞噬作用，或者是吞噬细胞内实际的PrP（CWD）复制。为了比较早期和晚期疾病中的淋巴细胞靶标，我们还检查了：（i）口服CWD暴露后3个月内小鹿淋巴细胞中PrP（CWD）的分布，以及（ii）自然感染CWD的临床前鹿的扁桃体活检。这些研究表明，PrP（CWD）的早期淋巴细胞分布与晚期疾病相似，即呈现出与FDC相关的模式。我们得出结论，在鹿中，PrP（CWD）主要在细胞外积累，并与FDC以及可能的B细胞相关——这一发现引发了关于负责病理性朊病毒产生的细胞的问题。
