Pintor M, Gómez J A, Ferrón L, Ferreirós C M, Criado M T
Departamento de Microbiología y Parasitología, Facultad de Farmacia, Universidad de Santiago de Compostela, Spain.
J Med Microbiol. 1998 Sep;47(9):757-60. doi: 10.1099/00222615-47-9-757.
Iron uptake analysis suggested that the Neisseria meningitidis transferrin (Tf) binding proteins, TbpA and TbpB, form only one type of receptor complex. Mutants defective in the synthesis of either TbpA or TbpB, but not defective in both proteins, can bind Tf, suggesting that both proteins are surface exposed and function in Tf binding. Also, iron uptake from Tf into the meningococci did not require the presence of both Tbps. The TbpB-defective mutant incorporated c. 37% of the iron taken up by the wild-type strain, but this was insufficient for bacterial growth. The TbpA-defective mutant incorporated c. 50% of the iron taken up by the wild-type strain and was able to grow with Tf as the only iron source. Mouse antibodies specific for TbpA were able to block c. 70% of the iron uptake from Tf in the wild-type strain, whereas they blocked only 22% of iron uptake in the TbpB-defective mutant and did not block uptake in the TbpA-defective strain. These results emphasise that TbpA should be considered in future vaccine trials in which iron-restricted proteins are to be included in the vaccine formulation.
铁摄取分析表明，脑膜炎奈瑟菌转铁蛋白（Tf）结合蛋白TbpA和TbpB仅形成一种类型的受体复合物。在TbpA或TbpB合成方面存在缺陷，但并非两种蛋白都有缺陷的突变体能够结合Tf，这表明这两种蛋白都暴露于表面并在Tf结合中发挥作用。此外，铁从Tf进入脑膜炎球菌并不需要两种Tbp同时存在。TbpB缺陷型突变体摄取的铁约为野生型菌株摄取量的37%，但这不足以支持细菌生长。TbpA缺陷型突变体摄取的铁约为野生型菌株摄取量的50%，并且能够以Tf作为唯一铁源生长。针对TbpA的小鼠抗体能够阻断野生型菌株中约70%的铁从Tf摄取，而在TbpB缺陷型突变体中仅阻断22%的铁摄取，在TbpA缺陷型菌株中则不阻断铁摄取。这些结果强调，在未来将铁限制蛋白纳入疫苗配方的疫苗试验中应考虑TbpA。
