Narayan O, Griffin D E, Silverstein A M
J Infect Dis. 1977 May;135(5):800-6. doi: 10.1093/infdis/135.5.800.
The influence of the age and immune status of the host on the slow replication and persistence of visna virus in sheep was studied. Twenty-five randomly bred fetal American lambs were inoculated intracerebrally with visna virus. Eight of these fetuses were immunosuppressed by thymectomy and antiserum to lymphocytes before inoculation. Fetuses were sacrificed sequentially, and tissues were processed for viral quantitation. No exponential increase of virus occurred in either the normal or immunosuppressed fetuses, and virus was recovered mainly by explanation of tissues. This finding indicated that the viral genome was present in tissue cells but that the extent of replication in the early phase of infection was restricted by factors unassociated with maturation or immune status of the host. In addition, virus isolated from the peripheral blood leukocytes of a sheep one year after inoculation was antigenically distinct from the plaque-purified virus used for inoculation. This distinction suggested that a major antigenic shift of the agent had occurred and provided another mechanism for the maintenance of the persistent infection.
研究了宿主的年龄和免疫状态对绵羊中维斯纳病毒缓慢复制和持续存在的影响。将25只随机繁育的美国胎羊脑内接种维斯纳病毒。其中8只胎羊在接种前通过胸腺切除术和淋巴细胞抗血清进行免疫抑制。依次处死胎羊，并对组织进行病毒定量处理。正常胎羊和免疫抑制胎羊中均未出现病毒的指数增长，且主要通过组织裂解来回收病毒。这一发现表明病毒基因组存在于组织细胞中，但感染早期的复制程度受到与宿主成熟或免疫状态无关的因素限制。此外，接种一年后从一只绵羊外周血白细胞中分离出的病毒在抗原性上与用于接种的噬斑纯化病毒不同。这种差异表明该病原体发生了主要的抗原转变，并为维持持续性感染提供了另一种机制。
