Design of a Non-glycosylated Outer Domain-derived HIV-1 gp120 Immunogen That Binds to CD4 and Induces Neutralizing Antibodies
Design of a Non-glycosylated Outer Domain-derived HIV-1 gp120 Immunogen That Binds to CD4 and Induces Neutralizing Antibodies
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DOI：
10.1074/jbc.m110.152272
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发表时间：
2010-08-27
影响因子：
4.8
通讯作者：
Varadarajan, Raghavan
中科院分区：
文献类型：
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作者：
Bhattacharyya, Sanchari;Rajan, Roshan Elizabeth;Varadarajan, Raghavan
人类免疫缺陷病毒1型（HIV - 1）包膜糖蛋白gp120的外结构域（OD）是疫苗设计的一个重要靶点，因为它包含许多保守表位，其中很大一部分是CD4结合位点。过去设计基于外结构域的免疫原的尝试收效甚微。我们报道了一种基于大肠杆菌表达的、基于外结构域的免疫原（ODEC）的设计和特性，它基于HxBc2毒株的序列。这种设计的ODEC免疫原缺失可变环V1V2和V3，并在gp120的内、外结构域界面处引入了11个设计的突变。生物物理研究表明，ODEC具有折叠结构且耐蛋白酶，而缺失设计突变的ODEC则极易聚集。与先前已鉴定的外结构域构建体不同，ODEC能结合CD4和广泛中和抗体b12，但不结合非中和抗体b6和F105。在兔子体内免疫后，ODEC具有高度免疫原性，其血清对4种B亚型和1种C亚型病毒（包括2种b12抗性病毒）显示出可测量的中和作用。相比之下，用gp120免疫的兔子血清不能中和任何病毒。ODEC是首个基于gp120片段的能产生显著中和抗体的免疫原实例。
The outer domain (OD) of the HIV-1 envelope glycoprotein gp120 is an important target for vaccine design as it contains a number of conserved epitopes, including a large fraction of the CD4 binding site. Attempts to design OD-based immunogens in the past have met with little success. We report the design and characterization of an Escherichia coli-expressed OD-based immunogen (ODEC), based on the sequence of the HxBc2 strain. The ODEC-designed immunogen lacks the variable loops V1V2 and V3 and incorporates 11 designed mutations at the interface of the inner and the outer domains of gp120. Biophysical studies showed that ODEC is folded and protease-resistant, whereas ODEC lacking the designed mutations is highly aggregation-prone. In contrast to previously characterized OD constructs, ODEC bound CD4 and the broadly neutralizing antibody b12 but not the non-neutralizing antibodies b6 and F105. Upon immunization in rabbits, ODEC was highly immunogenic, and the sera showed measurable neutralization for four subtype B and one subtype C virus including two b12-resistant viruses. In contrast, sera from rabbits immunized with gp120 did not neutralize any of the viruses. ODEC is the first example of a gp120 fragment-based immunogen that yields significant neutralizing antibodies.