Halliburton B L, Blazkovec A A
Infect Immun. 1975 Jan;11(1):1-7. doi: 10.1128/iai.11.1.1-7.1975.
Randomly bred pigs of both sexes were injected intracardially with one-half of a 50% lethal dose of Listeria monocytogenes. When infected animals were skin tested with 30 mug of a water-soluble extract of sonically disrupted Listeria, both males and females had uniformly detectable levels of delayed hypersensitivity (DH) 4 days after infection. In males, cutaneous hypersensitivity to Listeria antigens reached a peak on day 5 or 6 of infection, and high levels of DH persisted through the 7th week. In females, DH reached a peak on day 6 or 7, remained at this level through the 4th week, and then dropped sharply. Cutaneous reactivity was usually higher for males than for females, and differences between the sexes were statistically significant 5, 6, and 7 weeks after infection. Low levels of DH were still present 41 weeks (females) or 46 weeks (males) after infection. Assays to determine the number of viable Listeria present in spleen homogenates indicated that bacterial multiplication occurred only during the first 24 hours of infection. The number of Listeria declined steadily thereafter, and by day 13 no bacteria could be recovered from the spleens of infected animals. Spleen assays indicated that Listeria-infected animals of both sexes were resistant to a small challenge dose of Listeria given 48 hours, 7 days, or 2 weeks after the primary infection. Resistance to re-infection was absent in females challenged at 41 weeks and in males challenged at 46 weeks.
将50%致死剂量的单核细胞增生李斯特菌的一半通过心内注射给予随机繁殖的雌雄猪。当用30微克经超声破碎的李斯特菌的水溶性提取物对感染动物进行皮肤试验时，感染后4天，雄性和雌性动物均有一致可检测水平的迟发型超敏反应（DH）。在雄性动物中，对李斯特菌抗原的皮肤超敏反应在感染后第5天或第6天达到峰值，高水平的DH持续到第7周。在雌性动物中，DH在第6天或第7天达到峰值，在第4周一直保持在这个水平，然后急剧下降。雄性动物的皮肤反应性通常高于雌性动物，感染后第5、6和7周两性之间的差异具有统计学意义。感染后41周（雌性）或46周（雄性）仍存在低水平的DH。测定脾脏匀浆中活的李斯特菌数量的试验表明，细菌增殖仅发生在感染的最初24小时内。此后，李斯特菌数量稳步下降，到第13天，感染动物的脾脏中无法再分离到细菌。脾脏检测表明，初次感染后48小时、7天或2周给予小剂量李斯特菌攻击时，两性感染李斯特菌的动物均具有抵抗力。在41周时接受攻击的雌性动物和46周时接受攻击的雄性动物中不存在对再感染的抵抗力。
