Kim H, O'Rourke K I, Walter M, Purchase H G, Enck J, Shin T K
Pennsylvania Animal Diagnostic Laboratory System, Pennsylvania Veterinary Laboratory, Harrisburg 17025, USA.
J Vet Diagn Invest. 2001 Jan;13(1):89-91. doi: 10.1177/104063870101300120.
Following diagnosis of scrapie in a clinically suspect Suffolk sheep, 7 clinically normal flockmates were purchased by the Pennsylvania Department of Agriculture to determine their scrapie status using an immunohistochemical procedure. Two of the 7 euthanized healthy sheep had positive immunohistochemical staining of the prion protein of scrapie (PrP-Sc) in their brains, nictitating membranes, and tonsils. The PrP-Sc was localized in the areas of the brain where, histopathologically, there was neurodegeneration and astrocytosis. The PrP-Sc occurred within germinal centers of the affected nictitating membranes and tonsils and was located in the cytoplasm of the dendrite-like cells, lymphoid cells, and macrophages. These results confirm that immunohistochemical examination of the nictitating membrane can be used as a screen for the presence of scrapie infection in clinically normal sheep at a capable veterinary diagnostic laboratory. In sheep with a PrP-Sc-positive nictitating membrane, the diagnosis of scrapie should be confirmed by histopathology and immunohistochemical examination of the brain following necropsy. Following full validation, immunohistochemistry assays for detection of PrP-Sc in nictitating membrane lymphoid tissues can improve the effectiveness of the scrapie control and eradication program by allowing diagnosis of the disease in sheep before the appearance of clinical signs.
在一只临床疑似患痒病的萨福克绵羊被诊断出患有痒病后，宾夕法尼亚州农业部购买了7只临床正常的同群羊，用免疫组织化学方法确定它们的痒病感染状况。7只安乐死的健康绵羊中有2只在其大脑、瞬膜和扁桃体中，朊病毒蛋白（PrP-Sc）的免疫组织化学染色呈阳性。PrP-Sc定位于大脑中组织病理学上出现神经变性和星形细胞增生的区域。PrP-Sc出现在受影响瞬膜和扁桃体的生发中心内，位于树突状细胞、淋巴细胞和巨噬细胞的细胞质中。这些结果证实，在有能力的兽医诊断实验室，对瞬膜进行免疫组织化学检查可作为筛查临床正常绵羊痒病感染情况的一种方法。对于瞬膜PrP-Sc呈阳性的绵羊，应在尸检后通过组织病理学和大脑免疫组织化学检查来确诊痒病。经过全面验证后，用于检测瞬膜淋巴组织中PrP-Sc的免疫组织化学检测方法，可在绵羊出现临床症状之前诊断出疾病，从而提高痒病防控和根除计划的有效性。
