Narayan O, Kennedy-Stoskopf S, Zink M C
Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD 21205.
Ann Neurol. 1988;23 Suppl:S95-100. doi: 10.1002/ana.410230725.
The biological properties of the ruminant animal lentiviruses, visna and caprine arthritis-encephalitis viruses, closely resemble those of their human counterparts, the human immunodeficiency viruses (HIV). All of these viruses are morphologically identical and are disseminated from host to host in nature during exchange of body fluids. Artificial conditions that favor excess exchange of such fluids precipitate epidemics by these viruses. The strategy of replication of the animal viruses in tissue culture and in vivo are very similar to that of the human virus. Virus replication is highly productive in tissue culture and leads to cytopathic effects characterized by fusion. In vivo, the rate of virus replication is restricted and lesions, suggestive of an immunopathological origin, develop after prolonged periods of subclinical infection. Similar to the animal viruses, the human viruses have a tropism for macrophages in vivo, and this leads somehow to a loss of T helper lymphocytes and proliferation of cytotoxic lymphocytes. In addition, the viruses are highly neurotropic and this results in acute fulminating disease in neonatal hosts and chronic encephalopathy in adults. Both animal and human viruses cause persistent infections and have similar strategies for eluding host immune responses. These include sequestration of neutralizing epitopes, induction of low titers of neutralizing antibodies, and antigenic drift during persistent infection. Despite close homology between genetic sequences of HIV-I and -II, these two viruses seem to have as much biological disparity from each other as does visna virus from caprine arthritis-encephalitis virus. The latter two viruses induce neutralizing antibodies that are highly strain specific and show no cross protection.(ABSTRACT TRUNCATED AT 250 WORDS)
反刍动物慢病毒（绵羊肺腺瘤病毒和山羊关节炎-脑炎病毒）的生物学特性与人类对应病毒——人类免疫缺陷病毒（HIV）极为相似。所有这些病毒在形态上相同，在自然界中通过体液交换在宿主间传播。有利于此类液体过度交换的人工条件会引发这些病毒的流行。动物病毒在组织培养和体内的复制策略与人类病毒非常相似。病毒在组织培养中复制高效，并导致以融合为特征的细胞病变效应。在体内，病毒复制速度受限，在长期亚临床感染后会出现提示免疫病理起源的病变。与动物病毒类似，人类病毒在体内对巨噬细胞具有嗜性，这在某种程度上导致辅助性T淋巴细胞减少和细胞毒性淋巴细胞增殖。此外，这些病毒具有高度嗜神经性，这在新生宿主中导致急性暴发性疾病，在成年宿主中导致慢性脑病。动物病毒和人类病毒都会引起持续性感染，并且在逃避宿主免疫反应方面有相似的策略。这些策略包括中和表位的隔离、低滴度中和抗体的诱导以及持续性感染期间的抗原漂移。尽管HIV-I和-II的基因序列高度同源，但这两种病毒之间的生物学差异似乎与绵羊肺腺瘤病毒和山羊关节炎-脑炎病毒之间的差异一样大。后两种病毒诱导的中和抗体具有高度毒株特异性，且无交叉保护作用。（摘要截选至250词）
