Waldrop Julie G, Stringfellow David A, Galik Patricia K, Givens M Daniel, Riddell Kay P, Riddell M Gatz, Carson Robert L
College of Veterinary Medicine, Auburn University, 1500 Wire Road, Auburn, AL 36849, USA.
Theriogenology. 2006 Feb;65(3):594-605. doi: 10.1016/j.theriogenology.2005.04.034. Epub 2005 Jul 21.
Two recent studies demonstrated that a high-affinity isolate of BVDV (SD-1), remained associated with a small percentage of in vivo-derived bovine embryos following artificial exposure to the virus and either washing or trypsin treatment. Further, the embryo-associated virus was infective in an in vitro environment. Therefore, the objective of this study was to determine if the quantity of a high-affinity isolate of BVDV associated with single-washed or trypsin-treated embryos could cause infection in vivo. Twenty zona-pellucida-intact morulae and blastocysts (MB) were collected on day 7 from superovulated cows. After collection, all MB were washed according to International Embryo Transfer Society (IETS) standards, and all but 4 MB (negative controls) were exposed for 2 h to 10(5)-10(6) cell culture infective doses (50% endpoint) per milliliter (CCID(50)/mL) of viral strain SD-1. Following exposure, according to IETS standards, one half of the MB were washed and one half were trypsin treated. All MB were then individually sonicated, and sonicate fluids were injected intravenously into calves on day 0. Blood was drawn to monitor for viremia and(or) seroconversion. Seroconversion of calves injected with sonicate fluids from washed and trypsin-treated embryos occurred 38% and 13% of the time, respectively. Therefore, the quantity of a high-affinity isolate of BVDV associated with single-washed or trypsin-treated embryos was infective in vivo.
最近的两项研究表明，牛病毒性腹泻病毒（BVDV）的一种高亲和力分离株（SD-1），在人工感染该病毒并经过冲洗或胰蛋白酶处理后，仍与一小部分体内来源的牛胚胎相关联。此外，与胚胎相关的病毒在体外环境中具有感染性。因此，本研究的目的是确定与单次冲洗或胰蛋白酶处理的胚胎相关的BVDV高亲和力分离株的数量是否会在体内引起感染。在第7天从超排母牛中收集20个完整透明带的桑椹胚和囊胚（MB）。收集后，所有MB均按照国际胚胎移植协会（IETS）标准进行冲洗，除4个MB（阴性对照）外，其余所有MB均暴露于每毫升10(5)-10(6)细胞培养感染剂量（50%终点）（CCID(50)/mL）的病毒株SD-1中2小时。暴露后，按照IETS标准，一半的MB进行冲洗，另一半进行胰蛋白酶处理。然后对所有MB进行单独超声处理，并在第0天将超声处理液静脉注射到犊牛体内。采集血液监测病毒血症和（或）血清转化。注射经冲洗和胰蛋白酶处理胚胎的超声处理液的犊牛血清转化分别发生在38%和13%的时间。因此，与单次冲洗或胰蛋白酶处理的胚胎相关的BVDV高亲和力分离株的数量在体内具有感染性。
