The Staphylococcus aureus and Staphylococcus epidermidis transferrin-binding proteins are expressed in vivo during infection
The Staphylococcus aureus and Staphylococcus epidermidis transferrin-binding proteins are expressed in vivo during infection
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DOI：
10.1099/00221287-144-4-1005
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发表时间：
1998-04-01
期刊：
影响因子：
--
通讯作者：
Williams, P
中科院分区：
文献类型：
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作者：
Modun, BJ;Cockayne, A;Williams, P
葡萄球菌表达42 kDa的细胞壁相关蛋白，其作为哺乳动物铁结合糖蛋白转铁蛋白的受体发挥作用。为了确定这种转铁蛋白结合蛋白（TBP）是否在感染过程中表达，金黄色葡萄球菌和表皮葡萄球菌在大鼠腹腔内植入的腔室中体内生长。直接从腔室回收的葡萄球菌制备的细胞壁蛋白的SD 5-PAGE和Western印迹显示TBP和细菌表面相关的大鼠转铁蛋白的存在。为了获得葡萄球菌TBP在人体内表达的证据，对来自进行持续性非卧床腹膜透析（CAPD）的未感染患者的血清和人腹膜透析液（HPD）以及来自健康人类志愿者的血清进行抗TBP抗体筛选。Western免疫印迹显示，后一组的10份样品中有3份、10份HPD样品中有7份和10份CAPD患者血清样品中含有两种S.金黄色葡萄球菌和表皮为了进一步了解TBP抗体的出现，随时间从CAPD患者中收集HPD样本，这些患者在导管插入后立即采集的HPD样本缺乏抗TBP抗体。在这些患者中的两个中，每个人都经历了由于S.表皮葡萄球菌或人葡萄球菌感染后，在感染后立即收集的HPD中出现TBP抗体。为了确定这种TBP抗体是否能够阻断转铁蛋白与其葡萄球菌受体之间的相互作用，使用蛋白A-琼脂糖珠纯化HPD免疫球蛋白级分。在竞争试验中，这些免疫球蛋白阻断了I-125标记的转铁蛋白与全菌和分离的42 kDa S.金黄色葡萄球菌和表皮这些提供了证据表明，葡萄球菌TBP在感染过程中在体内表达。
Staphylococci express a 42 kDa cell-wall-associated protein which functions as a receptor for the mammalian iron-binding glycoprotein transferrin. To determine whether this transferrin-binding protein (TBP) is expressed during infection, Staphylococcus aureus and Staphylococcus epidermidis were grown in vivo in chambers implanted intraperitoneally in rats. SD5-PAGE and Western blotting of cell wall proteins prepared from staphylococci recovered directly from the chambers revealed the presence of both the TBP and bacterial-surface-associated rat transferrin. To obtain evidence for the in vivo expression of the staphylococcal TBPs in humans, sera and human peritoneal dialysate (HPD) from non-infected patients undergoing continuous ambulatory peritoneal dialysis (CAPD) and sera from healthy human volunteers were screened for anti-TBP antibodies. Western immunoblots revealed that three out of ten samples from the latter group, seven out of ten HPD samples and ten of ten CAPD patient serum samples contained antibodies to the TBP of both S. aureus and S. epidermidis. To gain further insights into the appearance of TBP antibodies, HPD samples were collected over time from CAPD patients whose HPD samples taken immediately after catheter insertion lacked anti-TBP antibodies. In two of these patients, each of whom experienced an episode of peritonitis due to S. epidermidis or Staphylococcus hominis, antibodies to the TBP appeared in the HPD collected immediately post-infection. To determine whether such TBP antibodies were capable of blocking interactions between transferrin and its staphylococcal receptor, HPD immunoglobulin fractions were purified using protein A-Sepharose beads. In competition assays, these immunoglobulins blocked the binding of I-125-labelled transferrin both to whole bacteria and to the isolated 42 kDa TBPs of S. aureus and S. epidermidis. These provide evidence to show that staphylococcal TBPs are expressed in vivo during infection.