Takemoto K K, Mattern C F, Stone L B, Coe J E, Lavelle G
J Virol. 1971 Mar;7(3):301-8. doi: 10.1128/JVI.7.3.301-308.1971.
Progressive pneumonia virus, the causative agent of a slow, pulmonary disease of Montana sheep, was shown to be antigenically related to two other slow viruses of sheep, visna and maedi. Electron microscopic examination of infected cells revealed that the virus matures by a budding process and that the budding particles as well as the mature, extracellular virions bear striking resemblances to the oncogenic ribonucleic acid (RNA) viruses. Recent findings of an RNA-dependent deoxyribonucleic acid polymerase associated with the virions of this group of slow viruses lend further support to the notion that they may tentatively be classified with the oncogenic RNA tumor viruses.
进行性肺炎病毒是蒙大拿州绵羊一种慢性肺部疾病的病原体，已证明它在抗原性上与绵羊的另外两种慢病毒——维斯纳病毒和梅迪病毒相关。对受感染细胞的电子显微镜检查显示，该病毒通过出芽过程成熟，并且出芽颗粒以及成熟的细胞外病毒粒子与致癌核糖核酸（RNA）病毒有显著相似之处。最近发现与这组慢病毒的病毒粒子相关的一种依赖RNA的脱氧核糖核酸聚合酶，进一步支持了它们可能暂时归类为致癌RNA肿瘤病毒的观点。
