Expression of factor H binding protein in meningococcal strains can vary at least 15-fold and is genetically determined
Expression of factor H binding protein in meningococcal strains can vary at least 15-fold and is genetically determined
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DOI：
10.1073/pnas.1521142113
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发表时间：
2016-03-08
影响因子：
11.1
通讯作者：
Masignani, Vega
中科院分区：
文献类型：
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作者：
Biagini, Massimiliano;Spinsanti, Marco;Masignani, Vega
因子H结合蛋白（fHbp）是脑膜炎奈瑟氏菌的脂蛋白，其对于该细菌在人血液中的存活是重要的，并且是两种最近许可的针对血清群B脑膜炎球菌（MenB）的疫苗的组分。基于866个不同的氨基酸序列，该蛋白被分为三个变体或两个家族。蛋白质的定量通过免疫测定法（例如ELISA或流式细胞仪）进行，这些测定法对蛋白质的序列变异和表达水平敏感。在此，选择反应监测质谱法用于代表MenB群体多样性的一大组菌株中fHbp的绝对定量。分析显示，fHbp表达水平可以变化至少15倍，并且变体1菌株比变体2或变体3菌株表达显著更多的蛋白质。对补体介导的杀伤的敏感性与不同脑膜炎球菌菌株表达的蛋白质的量相关，这可以从启动子区域的核苷酸序列预测。最后，绝对定量允许每个细胞的fHbp分子的数量的计算，并提出一个C1q，补体级联的识别组件的参与的机制模型。
Factor H binding protein (fHbp) is a lipoprotein of Neisseria meningitidis important for the survival of the bacterium in human blood and a component of two recently licensed vaccines against serogroup B meningococcus (MenB). Based on 866 different amino acid sequences this protein is divided into three variants or two families. Quantification of the protein is done by immunoassays such as ELISA or FACS that are susceptible to the sequence variation and expression level of the protein. Here, selected reaction monitoring mass spectrometry was used for the absolute quantification of fHbp in a large panel of strains representative of the population diversity of MenB. The analysis revealed that the level of fHbp expression can vary at least 15-fold and that variant 1 strains express significantly more protein than variant 2 or variant 3 strains. The susceptibility to complement-mediated killing correlated with the amount of protein expressed by the different meningococcal strains and this could be predicted from the nucleotide sequence of the promoter region. Finally, the absolute quantification allowed the calculation of the number of fHbp molecules per cell and to propose a mechanistic model of the engagement of C1q, the recognition component of the complement cascade.