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首页> 外文期刊>Infection and immunity >Adherence of Streptococcus agalactiae to synchronously growing human cell monolayers without lipoteichoic acid involvement.
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Adherence of Streptococcus agalactiae to synchronously growing human cell monolayers without lipoteichoic acid involvement.

机译：无乳链球菌对同步生长的人细胞单层的粘附，而无脂磷壁酸的参与。

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Freshly isolated virulent and nonvirulent strains of Streptococcus agalactiae type III were used to study differences in coccal adherence to synchronously dividing, subconfluent human embryonic amnion and fetal lung monolayers in vitro. The adherence frequency by virulent isolates of mid-logarithmically growing cocci to amnion cells varied markedly with host cell age, being highest shortly after eucaryotic cell division. This variation was not observed with lung cell monolayers, suggesting that cyclic production or exposure of coccal receptor sites on the eucaryotic cell surface with age is not a common property of all primary human cells in vitro. However, and regardless of age, not all cells within these synchronously dividing populations bound virulent cocci, indicating that a very small segment of a population may always be unresponsive to host cell interactions with a coccal pathogen. By comparison, adherence of nonvirulent coccal isolates to amnion and lung cells remained constant and of a very low order, regardless of host cell age. Maximal adherence of virulent S. agalactiae to young host cells occurred at early and mid-logarithmic phases of growth. However, at the late stationary growth phase, adherence was reduced to almost that of nonvirulent isolates. Pretreatment of virulent S. agalactiae with anti-lipoteichoic acid (LTA) serum failed to inhibit coccal adherence to these different host cells. Heat negated adherence. Group B coccal LTA was cytotoxic for these host cells. However, pretreatment of amnion and lung cells with nontoxic levels of this amphiphile did not prevent attachment of virulent cocci. Finally, coccal pretreatment with pronase abrogated adherence to either host cell even though surface-exposed LTA was uneffected, as observed by the indirect fluorescent-antibody procedure. Likewise, no observable difference in surface LTA was detected when fresh isolates of virulent and nonvirulent coccal strains were compared by this procedure. These studies suggest that protein involvement, rather than LTA, is primarily responsible for mediating virulent S. agalactiae type III attachment to these synchronously growing, subconfluent eucaryotic monolayers in vitro.
机译：新鲜分离的有毒和无毒力的无乳链球菌III型菌株用于研究球菌对体外同步分离，亚汇合的人胚胎羊膜和胎儿肺单层粘附的差异。对数生长期的球菌的强毒分离株对羊膜细胞的粘附频率随宿主细胞年龄的变化而显着变化，在真核细胞分裂后不久最高。在肺细胞单层中未观察到这种变化，这表明随着年龄的增长，循环产生或真核细胞表面的球蛋白受体位点的暴露并不是所有人类原代细胞的共同特性。但是，无论年龄大小，并不是这些同步分裂的群体中的所有细胞都结合了毒性球菌，这表明一小部分群体可能始终对宿主细胞与球菌病原体的相互作用无反应。相比之下，无毒球菌分离株对羊膜和肺细胞的粘附力保持恒定，并且处于非常低的水平，而与宿主细胞的年龄无关。有毒的无乳链球菌对年轻宿主细胞的最大粘附发生在生长的对数早期和中期。然而，在静止的后期生长阶段，依附性几乎降低至非毒性分离物。用抗脂蛋白酸（LTA）血清预处理强力无乳链球菌未能抑制球菌对这些不同宿主细胞的粘附。热量抵消粘附力。 B组球菌LTA对这些宿主细胞具有细胞毒性。但是，用无毒水平的两亲物预处理羊膜和肺细胞并不能阻止强力球菌的附着。最后，用间接酶抗体程序观察到，即使未暴露于表面的LTA，用链霉蛋白酶进行的球菌预处理也可消除对任一宿主细胞的粘附。同样，通过此程序比较有毒和无毒球菌菌株的新鲜分离株时，未检测到表面LTA的可观察差异。这些研究表明，蛋白质的参与而不是LTA的主要作用是在体外介导毒性III型无乳链球菌附着于这些同步生长，亚汇合的真核单层。

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