Visser L G, Hiemstra P S, van den Barselaar M T, Ballieux P A, van Furth R
Department of Infectious Diseases, Leiden University Hospital, The Netherlands.
Infect Immun. 1996 May;64(5):1653-8. doi: 10.1128/iai.64.5.1653-1658.1996.
The virulence plasmid pYVe of Yersinia enterocolitica codes for the production of the outer membrane protein YadA and the secretion of several proteins, called Yops, which may protect this bacterium against killing by human granulocytes. Granulocytes kill ingested microorganisms by oxygen-dependent and oxygen-independent mechanisms, the latter including antimicrobial polypeptides. The aim of this study was to determine whether virulent (pYVe+) Y. enterocolitica and plasmid-cured avirulent (pYVe-) Y. enterocolitica differ in susceptibility to antimicrobial polypeptides extracted from granules of human granulocytes. The acetic acid granule extract contained several polypeptides with antimicrobial activity against Y. enterocolitica as determined by gel overlay and radial diffusion assays. Two of these polypeptides were identified as lysozyme and defensins. pYVe+ Y. enterocolitica was less susceptible than pYVe- Y. enterocolitica to the antimicrobial activity of granule extract, lysozyme, and defensins as determined in a suspension assay, which indicated that the pYVe plasmid mediates a reduced susceptibility to these polypeptides. The role of YadA in the resistance to antimicrobial polypeptides was analyzed by using mutants of Y. enterocolitica that specifically lack or express YadA. The results demonstrated that YadA conferred resistance to the killing of Y. enterocolitica by the granule extract. Together, these results indicate that the plasmid-encoded factor YadA contributes to the resistance of Y. enterocolitica to the killing by antimicrobial polypeptides of human granulocytes.
小肠结肠炎耶尔森菌的毒力质粒pYVe编码外膜蛋白YadA的产生以及几种被称为Yops的蛋白的分泌，这些蛋白可能保护该细菌免受人类粒细胞的杀伤。粒细胞通过依赖氧和不依赖氧的机制杀死摄入的微生物，后者包括抗菌多肽。本研究的目的是确定有毒力的（pYVe+）小肠结肠炎耶尔森菌和质粒消除后的无毒力的（pYVe-）小肠结肠炎耶尔森菌在对从人类粒细胞颗粒中提取的抗菌多肽的敏感性上是否存在差异。通过凝胶覆盖法和径向扩散试验确定，乙酸颗粒提取物含有几种对小肠结肠炎耶尔森菌具有抗菌活性的多肽。其中两种多肽被鉴定为溶菌酶和防御素。在悬浮试验中确定，pYVe+小肠结肠炎耶尔森菌比pYVe-小肠结肠炎耶尔森菌对颗粒提取物、溶菌酶和防御素的抗菌活性更不敏感，这表明pYVe质粒介导了对这些多肽的敏感性降低。通过使用特异性缺乏或表达YadA的小肠结肠炎耶尔森菌突变体分析了YadA在对抗菌多肽抗性中的作用。结果表明，YadA赋予了小肠结肠炎耶尔森菌对颗粒提取物杀伤的抗性。总之，这些结果表明，质粒编码因子YadA有助于小肠结肠炎耶尔森菌抵抗人类粒细胞抗菌多肽的杀伤。
