United States Department of Agriculture, Agricultural Research Service, Pullman, WA 99164, USA.
BMC Vet Res. 2012 Apr 2;8:42. doi: 10.1186/1746-6148-8-42.
The United States control program for classical ovine scrapie is based in part on the finding that infection is typically spread through exposure to shed placentas from infected ewes. Transmission from goats to sheep is less well described. A suitable rodent model for examining the effect of caprine scrapie isolates in the ovine host will be useful in the ovine scrapie eradication effort. In this study, we describe the incubation time, brain lesion profile, glycoform pattern and PrPSc distribution patterns in a well characterized transgenic mouse line (Tg338) expressing the ovine VRQ prion allele, following inoculation with brain from scrapie infected goats.
First passage incubation times of caprine tissue in Tg338 ovinized mice varied widely but second passage intervals were shorter and consistent. Vacuolation profiles, glycoform patterns and paraffin-embedded tissue blots from terminally ill second passage mice derived from sheep or goat inocula were similar. Proteinase K digestion products of murine tissue were slightly smaller than the original ruminant inocula, a finding consistent with passage of several ovine strains in previous reports.
These findings demonstrate that Tg338 mice propagate prions of caprine origin and provide a suitable baseline for examination of samples identified in the expanded US caprine scrapie surveillance program.
美国对经典绵羊痒病的控制计划部分基于这样的发现，即感染通常是通过接触感染绵羊的脱落胎盘传播的。从山羊到绵羊的传播情况描述得较少。一种合适的啮齿动物模型，用于研究山羊痒病分离株对绵羊宿主的影响，将有助于绵羊痒病的根除工作。在这项研究中，我们描述了在感染山羊痒病的脑组织接种后，在表达绵羊 VRQ 朊病毒等位基因的特征明确的转基因小鼠系（Tg338）中潜伏期、脑病变谱、糖型模式和 PrPSc 分布模式。
第一阶段山羊组织在 Tg338 绵羊化小鼠中的潜伏期差异很大，但第二阶段的间隔时间更短且一致。来自绵羊或山羊接种物的终末期第二阶段感染小鼠的空泡形成谱、糖型模式和石蜡包埋组织印迹相似。与以前报道的几株绵羊株的传播一致，来自鼠组织的蛋白酶 K 消化产物略小于原始反刍动物接种物。
这些发现表明，Tg338 小鼠可传播源自山羊的朊病毒，并为检查在美国扩大的山羊痒病监测计划中发现的样本提供了合适的基线。
