Developing Immunogens to Elicit Broadly Neutralizing anti-HIV-1 Antibodies

联合国艾滋病规划署记录了每年数百万新的HIV-1感染病例，因此HIV-1疫苗具有很高的安全性 令人向往。到目前为止，尽管作出了许多努力，但没有一种免疫方案能够重复地产生广泛的中和作用。 抗HIV-1抗体(BNAbs)。最近可用的类本地HIV-1包膜尖峰(Env)三聚体诱导 中和自体第二层病毒的抗体，但这些抗体的效力和广度有限。 推测bNAbs的生殖系(IGL)抗体前体一般不与HIV-1环境结合的观察 蛋白质或中和HIV-1表明，合理设计的IGL靶向Env免疫原将是 启动bNAb响应所需的。比约克曼博士和努森茨韦格博士提出了一个高度合作的项目 将这种方法应用于两类HIV-1 bNAbs的靶表位：一类与PGT121相关的结合 与V3可变环的碱基结合，并与N332gp120多聚糖(V3/N332 bNAbs)和IOMA样蛋白相互作用 BNAbs，一类源于VH1-2生殖系基因的新的模拟CD4结合位点(CD4bs)bNAbs 细分市场。之所以选择V3/N332和IOMA类，是因为(I)V3/N332抗体是最有效的 (Ii)IOMA相对较低 体细胞超突变的数量及其正常长度的CDRL3表明，它可能比 VRC01类VH1-2衍生的CD4bs bNAbs是严重体细胞突变的，含有稀有的5-残基 CDRL3，和(Iii)免疫原设计将有助于天然糖基化环境的晶体结构 与V3/N332bNAb 10-1074和IOMA结合的三聚体。比约克曼实验室将制造免疫原来瞄准 IGLS和牧羊人bNAb成熟，而Nussenzweig实验室开发免疫计划以诱导 使用所设计的免疫原的bNAbs。Nussenzweig实验室的具体目标是：(1)开发和简化 在IGL敲入小鼠中诱导抗V3/N332抗体的免疫方案，(2)适应免疫方案 针对V3/N332 bNAbs在转基因小鼠、野生型和携带未重排的AlivaMab小鼠中的研制 人类抗体位点，(3)制定免疫方案以诱导IOMA样抗体，以及(4)确定 未感染人群幼稚B细胞库中IOMA和V3/N332bNAb前体的频率 捐赠者。比约克曼实验室的具体目标是：(1)解决免疫球蛋白免疫原复合体的结构，以帮助 基于结构的免疫原设计，(2)利用基于结构的设计和文库筛选来鉴定环境 与V3/N332免疫球蛋白高亲和力结合的三聚体，(3)利用结构信息指导酵母的构建 展示文库以寻找与IOMA IGL结合的稀有变体，(4)结合结果创建环境三聚体免疫原 与两种bNAbs的免疫球蛋白结合，并与Nussenzweig博士合作评估双重和单一免疫原 老鼠。这些努力将得到核心A(自动细胞/生化分析)和核心B(蛋白质)的支持 表达)。拟议的实验将通过以下方式产生在猕猴身上进行的候选免疫原测试 合作者马尔科姆·马丁博士和疫苗在人体上的试验。

UNAIDS has documented millions of new HIV-1 infections every year, thus a vaccine for HIV-1 is highly desirable. To date, despite numerous efforts, no immunization regimen reproducibly elicits broadly neutralizing antibodies (bNAbs) against HIV-1. Recently available native-like HIV-1 envelope spike (Env) trimers elicit antibodies that neutralize autologous tier-2 viruses but these antibodies have only limited potency and breadth. The observations that inferred germline (iGL) antibody precursors of bNAbs do not generally bind HIV-1 Env proteins or neutralizing HIV-1 suggested that rationally designed iGL-targeting Env immunogens would be required to initiate bNAb responses. Drs. Bjorkman and Nussenzweig propose a highly collaborative project to apply this approach to target epitopes of two classes of HIV-1 bNAbs: a class related to PGT121 that binds to the base of the V3 variable loop and interacts with the N332gp120 glycan (V3/N332 bNAbs), and IOMA-like bNAbs, a new class of CD4-mimetic CD4 binding site (CD4bs) bNAbs derived from the VH1-2 germline gene segment. The V3/N332 and IOMA classes were chosen because (i) V3/N332 Abs are among the most potent of bNAbs and are commonly found in HIV-infected individuals who develop bNAbs, (ii) IOMA's relatively low number of somatic hypermutations and its normal-length CDRL3 suggest it may be more easily elicited than VRC01-class VH1-2–derived CD4bs bNAbs that are heavily somatically mutated and contain rare 5-residue CDRL3s, and (iii) immunogen design will be facilitated the crystal structure of a natively-glycosylated Env trimer bound to the V3/N332 bNAb 10-1074 and to IOMA. The Bjorkman lab will create immunogens to target iGLs and shepherd bNAb maturation, while the Nussenzweig lab develops immunization schemes to elicit bNAbs using the designed immunogens. The Nussenzweig lab specific aims are: (1) Develop and simplify immunization protocols that elicit bNAbs to V3/N332 in iGL knock-in mice, (2) Adapt immunization protocols developed for V3/N332 bNAbs in knock-in mice to wild type and AlivaMab mice that carry un-rearranged human antibody loci, (3) Develop an immunization protocol to elicit IOMA-like antibodies, and (4) Determine the frequency of IOMA and V3/N332 bNAb precursors in the naïve B cell repertoire of un-infected human donors. The Bjorkman lab specific aims are: (1) Solve structures of iGL–immunogen complexes to aid in structure-based immunogen design, (2) Use structure-based design and library screening to identify Env trimers that bind V3/N332 iGLs with high affinity, (3) Use structural information to guide construction of a yeast display library to find rare variants that bind IOMA iGL, (4) Combine results to create Env trimer immunogens that bind iGLs of both bNAbs and work with Dr. Nussenzweig to evaluate double and single immunogens in mice. These efforts will be supported by Core A (Automated cell/biochemical assays) and Core B (Protein Expression). The proposed experiments will produce candidate immunogens testing in macaques by collaborator Dr. Malcolm Martin and for vaccine trials in humans.