Howard D K, Schlom J
Proc Natl Acad Sci U S A. 1978 Nov;75(11):5718-22. doi: 10.1073/pnas.75.11.5718.
Host-range variants of mouse mammary tumor virus (MMTV) have been isolated that have the ability to productively infect cells in vitro with high efficiency (at multiplicities of infection </=1) and with extremely short latent periods to the production of de novo virus (as short as 4 days after infection). These variants of the highly oncogenic MMTV of RIII, C3H, and GR mice were obtained by serial virus passage in feline cells. The resultant variant stocks react in group-specific radioimmunoassays for the MMTV major external glycoprotein (gp52) and major internal protein (p28), possess a protein profile similar to that of wild-type MMTV, and contain a virion-associated DNA polymerase with a magnesium cation preference. Addition of dexamethasone and insulin to culture media enhances the titer of de novo MMTV to levels of approximately 10(10) particles per 75-cm(2) flask (containing 5 x 10(6) cells) per 24 hr. Variant stocks exhibit no evidence of contamination with either murine or feline type C retroviruses, as assayed by various techniques. The variants of MMTV derived from C3H and RIII mice exhibit differential host ranges that include the ability to productively infect feline, canine, bat, mink, murine, and human cells. Use of these MMTV host-range variants now facilitates the study of the complete replicative cycle of MMTV as well as an elucidation of the interaction of MMTV with various hormones, physical or chemical carcinogens, and tumor promoters in the initiation and promotion of mammary neoplasia.
已分离出小鼠乳腺肿瘤病毒（MMTV）的宿主范围变体，这些变体能够在体外高效地（感染复数≤1）、以极短的潜伏期（感染后短至4天）产生新病毒，从而有效感染细胞。这些来自RIII、C3H和GR小鼠的高度致癌MMTV变体是通过在猫细胞中连续传代病毒获得的。所得的变体病毒株在针对MMTV主要外膜糖蛋白（gp52）和主要内膜蛋白（p28）的群特异性放射免疫分析中发生反应，具有与野生型MMTV相似的蛋白质谱，并含有一种偏好镁阳离子的病毒体相关DNA聚合酶。向培养基中添加地塞米松和胰岛素可将新产生的MMTV滴度提高到每24小时约10（10）个颗粒/75平方厘米培养瓶（含5×10（6）个细胞）的水平。通过各种技术检测，变体病毒株没有显示出被鼠类或猫类C型逆转录病毒污染的迹象。源自C3H和RIII小鼠的MMTV变体表现出不同的宿主范围，包括能够有效感染猫、犬、蝙蝠、水貂、鼠和人类细胞。这些MMTV宿主范围变体的使用现在有助于研究MMTV的完整复制周期，以及阐明MMTV在乳腺肿瘤发生的起始和促进过程中与各种激素、物理或化学致癌物以及肿瘤促进剂的相互作用。
