Collins F M
Infect Immun. 1973 Dec;8(6):868-75. doi: 10.1128/iai.8.6.868-875.1973.
Specific pathogen-free CD-1 mice are highly susceptible to infection by Pasteurella multocida strain 5A whether introduced intravenously, intraperitoneally, subcutaneously, or aerogenically. The growth of the challenge organism in the blood, liver, spleen, lung, and peritoneal cavity was quantitated hourly for up to 12 h. Unvaccinated mice died 9 to 12 h after intravenous challenge due to the uncontrolled growth of the organism in all tissues tested. The rate of removal of the bacteria from the blood and of phagocytosis by peritoneal macrophages was extremely slow. In the absence of specific opsonins, more than 90% of the unopsonized challenge inoculum remained in the extracellular growth phase throughout the challenge period. Vaccination of mice with two doses of 10(8) heat-killed (60 C for 60 min) P. multocida given 7 days apart protected the mice against 100 to 1,000 lethal challenge doses. Survival data and growth curves obtained for both actively and passively immunized mice indicated that a humorally mediated immune mechanism was involved. Peak resistance to challenge occurred 21 to 28 days after the mice received the second dose of antigen, and this correlated with an 8- to 16-fold increase in specific agglutinin titers over the same time. Resistance to aerogenic challenge by vaccinated mice was less effective than when other routes of infection were used. The significance of these findings is discussed.
无特定病原体的CD-1小鼠无论通过静脉内、腹腔内、皮下或空气传播途径感染多杀巴斯德菌5A菌株均高度易感。在长达12小时的时间内，每小时对攻击菌在血液、肝脏、脾脏、肺和腹腔中的生长情况进行定量。未接种疫苗的小鼠在静脉内攻击后9至12小时死亡，原因是该菌在所有测试组织中不受控制地生长。细菌从血液中清除的速率以及腹膜巨噬细胞的吞噬作用极其缓慢。在没有特异性调理素的情况下，在整个攻击期间，超过90%的未调理攻击接种物仍处于细胞外生长阶段。给小鼠间隔7天接种两剂10(8)个经热灭活（60℃ 60分钟）的多杀巴斯德菌，可保护小鼠抵抗100至1000个致死攻击剂量。对主动免疫和被动免疫小鼠获得的存活数据和生长曲线表明，涉及一种体液介导的免疫机制。小鼠接受第二剂抗原后21至28天出现对攻击的峰值抵抗力，这与同一时间内特异性凝集素滴度增加8至16倍相关。接种疫苗的小鼠对空气传播攻击的抵抗力不如使用其他感染途径时有效。讨论了这些发现的意义。
