Shimoji Y, Yokomizo Y, Sekizaki T, Mori Y, Kubo M
National Institute of Animal Health, Ibaraki, Japan.
Infect Immun. 1994 Jul;62(7):2806-10. doi: 10.1128/iai.62.7.2806-2810.1994.
Three avirulent insertional mutants of Erysipelothrix rhusiopathiae were obtained by the technique of transposon mutagenesis with the self-conjugative transposon Tn916. The interactions between murine polymorphonuclear leukocytes and parent and mutant strains were studied in vitro. In the presence of normal serum, the virulent parent strain was resistant to phagocytosis, whereas the avirulent mutant strains were efficiently phagocytosed. In the presence of immune serum, the parent and the mutant strains were both efficiently phagocytosed. Electron microscopic examination of the parent strain demonstrated the presence of a structure resembling a capsule which was absent on the mutant strains, suggesting that a capsule may be involved in virulence. This was confirmed in studies in which an avirulent mutant strain reverted to virulence following acquisition of a capsule when the transposon was lost by spontaneous excision. These results strongly suggest that virulence of E. rhusiopathiae is associated, at least in part, with resistance to phagocytosis by polymorphonuclear leukocytes and that this antiphagocytic ability of the bacterium results from its possession of a capsule.
通过使用自共轭转座子Tn916的转座子诱变技术，获得了3株猪丹毒杆菌无毒插入突变体。在体外研究了小鼠多形核白细胞与亲本菌株和突变菌株之间的相互作用。在正常血清存在的情况下，有毒力的亲本菌株对吞噬作用具有抗性，而无毒力的突变菌株则被有效地吞噬。在免疫血清存在的情况下，亲本菌株和突变菌株均被有效地吞噬。对亲本菌株的电子显微镜检查显示存在一种类似于荚膜的结构，而突变菌株上不存在这种结构，这表明荚膜可能与毒力有关。这在以下研究中得到了证实：当转座子通过自发切除而丢失时，一株无毒力的突变菌株在获得荚膜后恢复了毒力。这些结果强烈表明，猪丹毒杆菌的毒力至少部分与对多形核白细胞吞噬作用的抗性有关，并且该细菌的这种抗吞噬能力是由于其具有荚膜。
