Hormaeche C E
Immunology. 1979 Jun;37(2):311-8.
The mechanisms of natural resistance to intravenous challenge with Salmonella typhimurium C5 are complex. LD50 determinations showed inbred mouse strains of low, intermediate and high natural resistance, with BALB/c and B10 strains the most susceptible, A/J the most resistant. Delayed (footpad) hypersensitivity was not by itself a measure of natural resistance. Resistant mouse strains sensitized either s.c. or i.v. with an attenuated salmonella strain showed positive 48 h footpad reactions when tested 8 days later with a salmonella extract, but three very susceptible strains also showed positive reactions. Determinations of the in vivo net growth rate of salmonellae in the liver and spleen during the first phase of the infection (up to day 4) arrange the different mouse strains into two categories of fast and slow net growth rate. All fast net growth rate strains are susceptible, but not all slow net growth rate strains are resistant. Besides slow net growth rate, resistance requires the participation of other factors appearing in the second phase of the infection (towards the end of the first week) probably involving the cellular immune response, which halts further bacterial growth. Not all slow net growth rate strains are equally capable of suppressing bacterial growth in this second phase. The host mechanism determining slow net growth rate is inherited as a dominant trait, and appears to be operating before the main cellular immune response. The influence of this mechanism on net growth rate is reflected in the time to death following a given dose of salmonellae. The present results suggest that overall resistance to salmonellae is polygenic, but that the mechanism responsible for the differences in early net growth rate is less complex.
对鼠伤寒沙门氏菌C5静脉内攻击产生天然抵抗力的机制很复杂。半数致死量（LD50）测定显示，近交系小鼠存在低、中、高天然抵抗力，其中BALB/c和B10品系最易感，A/J品系最具抵抗力。迟发型（足垫）超敏反应本身并非天然抵抗力的衡量指标。用减毒沙门氏菌菌株经皮下或静脉注射致敏的抗性小鼠品系，在8天后用沙门氏菌提取物检测时，48小时足垫反应呈阳性，但三个非常易感的品系也呈阳性反应。在感染的第一阶段（至第4天），对肝脏和脾脏中沙门氏菌的体内净生长速率进行测定，可将不同的小鼠品系分为净生长速率快和慢的两类。所有净生长速率快的品系都易感，但并非所有净生长速率慢的品系都有抗性。除了净生长速率慢之外，抗性还需要感染第二阶段（接近第一周结束时）出现的其他因素参与，可能涉及细胞免疫反应，从而阻止细菌进一步生长。并非所有净生长速率慢的品系在第二阶段抑制细菌生长的能力都相同。决定净生长速率慢的宿主机制作为显性性状遗传，并且似乎在主要细胞免疫反应之前起作用。这种机制对净生长速率的影响反映在给予一定剂量沙门氏菌后的死亡时间上。目前的结果表明，对沙门氏菌的总体抗性是多基因的，但导致早期净生长速率差异的机制不太复杂。
