Biological activity of serum antibodies to a nonacylated form of lipoprotein D of Haemophilus influenzae
Biological activity of serum antibodies to a nonacylated form of lipoprotein D of Haemophilus influenzae
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DOI：
10.1128/iai.64.11.4586-4592.1996
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发表时间：
1996-11-01
影响因子：
3.1
通讯作者：
Forsgren, A
中科院分区：
文献类型：
--
作者：
Akkoyunlu, M;Janson, H;Forsgren, A
蛋白D是一种表面暴露的42 kDa膜脂蛋白，在b型和非分型流感嗜血杆菌菌株中都很保守，被认为是预防流感嗜血杆菌感染的疫苗。在这里，我们报道了从高表达蛋白D(Pdm)的大肠杆菌的周质空间中大规模纯化一种非酰化形式的蛋白D(Pdm)。对人血清中的丙二醛抗体水平的筛查表明，6个月以下婴儿的免疫球蛋白G(IgG)抗体水平高于背景水平。在6个月至1岁的年龄组中，随着背景值的下降，免疫球蛋白抗体水平在1岁后开始上升，同时IgA抗体水平也开始上升。血清IgM抗体首次出现在6个月至1岁的婴儿，其抗体水平已降至出生后背景水平。来自人类和来自pdm免疫的大鼠的亲和纯化抗体检测到通常暴露在细菌表面的蛋白D表位。在酸性缓冲液中洗脱的亲和力分离的人抗丙二醛抗体对流感嗜血杆菌无杀菌作用。在这种缓冲液中可能会发生杀菌活性的丧失，正如在同一缓冲液中孵育后具有高杀菌活性的混合人血清中所证明的那样。丙型肝炎病毒超强免疫大鼠后，可产生较高水平的抗体，对同源和异种流感嗜血杆菌均有明显的杀菌活性。
Protein D, a surface-exposed 42-kDa membrane lipoprotein, is well conserved among both type b and non-typeable Haemophilus influenzae strains, and is considered a vaccine against H. influenzae infections. Here, we report the large-scale purification of a nonacylated form of protein D (PDm) from the periplasmic space of Escherichia coli overexpressing PDm. Screening of human sera for levels of antibodies to PDm demonstrated that the immunoglobulin G (IgG) antibody level is above background levels in infants less than 6 months of age. Following a drop to background values in the age group 6 months to 1 year, IgG antibody levels start to increase, together with IgA antibody levels, after 1 year of age. The first appearance of serum IgM antibodies is in 6-month to 1-year-old infants whose IgG antibody levels have dropped to the postnatal background level. Affinity-purified antibodies from humans and from PDm-immunized rats detected epitopes of protein D which are normally exposed on the bacterial surface. Affinity-isolated human anti-PDm antibodies eluted in acidic buffer were not bactericidal against H. influenzae. Loss of bactericidal activity may occur in this buffer, as was demonstrated in pooled human sera with high bactericidal activity after incubation in the same buffer. Hyperimmunization of rats with PDm induced high levels of serum IgG and IgA antibodies against PDm and significant bactericidal activity against homologous and heterologous H. influenzae strains.