Andron LA I I, Eigelsbach H T
Infect Immun. 1975 Jul;12(1):137-42. doi: 10.1128/iai.12.1.137-142.1975.
Ribonucleic acid (RNA)-rich extracts derived from the attenuated strain of Francisella tularensis (strain LVS) protected Swiss mice against lethal challenge with F. tularensis strain 425 but not against strain SCHU S4. No killed preparation, including an RNA-rich extract from SCHU S4 itself, offered protection against strain SCHU S4 in contrast to the high level of protection offered against this strain by vaccination with live strain LVS. The protective activity observed against strain 425 was sensitive to ribonuclease but not to Pronase. Protective activity is not a general property of bacterial RNA, since RNA-rich extracts from Staphylococcus aureus offered no protection against tularemia, although disc gel electrophoresis showed similar kinds and amounts of RNA in preparations form F. tularensis and S. aureus. Furthermore, inability to localize activity to a specific region in sucrose gradients suggests a structural rather than an informational role for the RNA in such extracts. RNA-rich extracts from F. tularensis but not from S. aureus were efficient inducers of F. tularensis opsonins in mouse serum, suggesting one mechanism by which such extracts confer protection.
源自土拉弗朗西斯菌减毒株（LVS株）的富含核糖核酸（RNA）的提取物可保护瑞士小鼠免受土拉弗朗西斯菌425株的致死性攻击，但对SCHU S4株无效。与用活LVS株疫苗接种对该菌株提供的高水平保护形成对比的是，包括来自SCHU S4本身的富含RNA的提取物在内的任何灭活制剂均不能提供针对SCHU S4株的保护。观察到的针对425株的保护活性对核糖核酸酶敏感，但对链霉蛋白酶不敏感。保护活性并非细菌RNA的普遍特性，因为来自金黄色葡萄球菌的富含RNA的提取物对兔热病没有保护作用，尽管圆盘凝胶电泳显示来自土拉弗朗西斯菌和金黄色葡萄球菌的制剂中的RNA种类和数量相似。此外，无法将活性定位到蔗糖梯度中的特定区域表明此类提取物中的RNA起结构作用而非信息作用。来自土拉弗朗西斯菌而非金黄色葡萄球菌的富含RNA的提取物是小鼠血清中土拉弗朗西斯菌调理素的有效诱导剂，提示了此类提取物提供保护的一种机制。
