Bolin S R, Littledike E T, Ridpath J F
USDA, Agricultural Research Service, National Animal Disease Center, Ames, IA 50010.
Am J Vet Res. 1991 Jul;52(7):1033-7.
Samples of sera were obtained from 5,725 cows in a semiclosed herd. In each of the preceding 7 years, the herd was vaccinated against bovine viral diarrhea (BVD) with killed virus. Neutralizing antibody tests were done on all samples of sera, using cytopathic virus, BVD-TGAC virus, that was antigenically distinct from the vaccine virus. Most samples of sera had high titers of neutralizing antibodies against BVD-TGAC virus. In 48 samples of sera, neutralizing antibodies were not detected against BVD-TGAC virus, but were detected against the vaccine virus. Neutralizing antibodies against selected noncytopathic BVD viruses were not detected in several samples of serum that had neutralizing antibodies against the vaccine virus and BVD-TGAC virus. Noncytopathic BVD virus was isolated from sera obtained from 3 cows less than 4 years old. Two cows were available for further testing, and persistent infection with BVD virus was confirmed in both cows. The BVD viruses isolated from those cows were not neutralized by several samples of sera. Immunoprecipitation of polypeptides induced by the vaccine virus was done with selected samples of serum. Two patterns of immuno-precipitated viral-induced polypeptides were identified. One pattern was consistent with exposure of cows with live virus. The other pattern was consistent with exposure of cows with only the killed virus vaccine.
从一个半封闭牛群的5725头奶牛中采集血清样本。在之前的7年里，该牛群每年都接种灭活病毒的牛病毒性腹泻（BVD）疫苗。使用细胞病变病毒BVD-TGAC病毒（其抗原性与疫苗病毒不同）对所有血清样本进行中和抗体检测。大多数血清样本对BVD-TGAC病毒具有高滴度的中和抗体。在48份血清样本中，未检测到针对BVD-TGAC病毒的中和抗体，但检测到了针对疫苗病毒的中和抗体。在一些对疫苗病毒和BVD-TGAC病毒具有中和抗体的血清样本中，未检测到针对选定的非细胞病变BVD病毒的中和抗体。从3头4岁以下奶牛的血清中分离出非细胞病变BVD病毒。有2头奶牛可供进一步检测，且证实这两头奶牛均存在BVD病毒持续感染。从这些奶牛中分离出的BVD病毒不能被几份血清样本中和。用选定的血清样本对疫苗病毒诱导的多肽进行免疫沉淀。鉴定出两种免疫沉淀的病毒诱导多肽模式。一种模式与奶牛感染活病毒一致。另一种模式与奶牛仅接触灭活病毒疫苗一致。
