Jeffrey M, Martin S, Thomson J R, Dingwall W S, Begara-McGorum I, González L
Lasswade Veterinary Laboratory, Veterinary Laboratories Agency, Pentlands Science Park, Penicuik, Midlothian, EH26 0PZ, UK.
J Comp Pathol. 2001 Jul;125(1):48-57. doi: 10.1053/jcpa.2001.0476.
Tonsillar biopsies (single or multiple) or necropsies, or both, were performed on sheep taken from a Suffolk flock in which frequent cases of scrapie had occurred over a period of several years. Clinically affected sheep of the susceptible PrP(AQ/AQ)genotype had widespread disease-specific PrP accumulation in the central nervous system (CNS), lymphoreticular system and peripheral ganglia. In nine healthy PrP(AQ/AQ)Suffolk sheep between 4 and 7 years of age, PrP could not be demonstrated post mortem in any of the lymphoreticular tissues, or in the peripheral ganglia or CNS. Tonsillar biopsies taken from animals of the resistant PrP(AR/AR)and PrP(AR/AQ)genotypes at age 3, 8, 14, 20 or 26 months did not show PrP accumulation. Disease- specific PrP accumulation in tonsillar biopsies from PrP(AQ/AQ)sheep was not seen in 20 animals aged 3 months, but was found in two of 10 animals at age 8 months and in eight of 10 animals at age 20 months. The numbers of PrP-positive tonsillar biopsies obtained from sheep previously biopsied on more than one occasion was greater than the number of positive tonsils obtained from other susceptible sheep of comparable ages. The earliest disease-specific PrP accumulation seen was in tingible body macrophages within germinal centres and only later was it detected in cells resembling follicular dendritic cells. Fourteen PrP(AQ/AQ)sheep examined post mortem at up to 17 months of age and which had not previously been biopsied or were biopsied only once had no CNS or tonsillar PrP accumulations. Two of these sheep subjected to necropsy at 14 months had PrP accumulation in lymphoreticular tissue, where it was confined to the mesenteric lymph nodes. In susceptible sheep, only low levels of immunohistochemically detectable PrP were present in a minority of follicles from tonsillar biopsies of young lambs, but by 14 months of age widespread PrP accumulation, affecting many or even all follicles, was present. Although clinical cases had widespread PrP accumulations in viscera, susceptible survivors had no such accumulations in tissues of the lymphoreticular system, peripheral nervous system or CNS, suggesting that some animals were not exposed to infection or were exposed to a non-infectious dose.
对取自一个萨福克羊群的绵羊进行了扁桃体活检（单次或多次）或尸检，或两者皆做，该羊群在几年时间里频繁出现羊瘙痒病病例。临床受影响的具有易感PrP(AQ/AQ)基因型的绵羊在中枢神经系统（CNS）、淋巴网状系统和外周神经节中出现广泛的疾病特异性PrP蓄积。在9只4至7岁的健康PrP(AQ/AQ)萨福克绵羊中，死后在任何淋巴网状组织、外周神经节或CNS中均未检测到PrP。对3、8、14、20或26月龄的具有抗性PrP(AR/AR)和PrP(AR/AQ)基因型的动物进行扁桃体活检，未发现PrP蓄积。在20只3月龄的PrP(AQ/AQ)绵羊的扁桃体活检中未见到疾病特异性PrP蓄积，但在10只8月龄的动物中有2只出现，在10只20月龄的动物中有8只出现。从之前多次接受活检的绵羊获得的PrP阳性扁桃体活检数量多于从其他年龄相当的易感绵羊获得的阳性扁桃体数量。最早见到的疾病特异性PrP蓄积出现在生发中心的吞噬细胞内，随后才在类似滤泡树突状细胞的细胞中检测到。对14只年龄达17个月且此前未接受活检或仅接受过一次活检的PrP(AQ/AQ)绵羊进行尸检，其CNS或扁桃体中均无PrP蓄积。其中2只在14个月时进行尸检的绵羊在淋巴网状组织中有PrP蓄积，局限于肠系膜淋巴结。在易感绵羊中，幼龄羔羊扁桃体活检的少数滤泡中仅存在低水平的免疫组化可检测PrP，但到14月龄时出现广泛的PrP蓄积，影响许多甚至所有滤泡。虽然临床病例在内脏中有广泛的PrP蓄积，但易感存活者在淋巴网状系统、外周神经系统或CNS的组织中没有此类蓄积，这表明一些动物未接触感染或接触的是无感染性剂量。
