Project 2: Design and screening for immunogens to efficiently elicit anti-HIV-1 bNAbs

项目2：设计和筛选有效诱导抗HIV-1 bNAbs的免疫原 有效的HIV疫苗可能需要诱导抗HIV-1 Env的抗体，并在大多数人中和 流行的病毒株(广谱中和抗体；bNAbs)。因为注射的bNAbs具有保护性 在动物模型中对抗HIV-1感染，人们普遍认为诱导bNAbs的疫苗可以预防 感染。疫苗努力尚未成功预防艾滋病毒-1感染和/或引发 BNAbs可能与观察到的推断生殖系(IGL)形式的bNAbs很少与环境结合有关 作为bNAbs靶标的蛋白质。用于疫苗设计的种系靶向方法涉及工程 一种IGL结合的Env蛋白，优先激活bNAb前体并选择多产体细胞 亲和力成熟过程中的超突变(SHM)。产生的存储器B单元然后通过顺序增强 免疫原通过选择额外的生产性SHM来引导bNAb的生产。比约克曼博士和 Nussenzweig建议将这种方法应用于两类HIV-1 bNAb：与PGT121相关的一类 它与V3可变环的碱基结合并与N332gp120多糖(V3/N332 bNAbs)相互作用，以及 IOMA样bNAbs--一类源于VH1-2的新的模拟CD4结合位点(CD4bs)bNAbs 生殖系基因片段。之所以选择V3/N332和IOMA类，是因为(I)V3/N332抗体属于 最有效的bNAbs，通常在产生bNAbs的艾滋病毒感染者中发现，以及 免疫基因研究将是评估被动注射V3/N332的人体临床试验的补充 BNab 10-1074给HIV-1感染者，(Ii)IOMA相对较少的SHM数量及其正常长度 CDRL3提示，它可能比VRC01类VH1-2衍生的CD4b bNAbs更容易诱导，后者是 严重的体细胞突变和含有罕见的5-残基CDRL3，以及(Iii)将促进免疫原的设计 通过与V3/N332bNAb 10-1074结合的天然糖基化的环境三聚体的最近结构和 爱荷马。目标是创建基于SOSIP的环境三聚体，以针对IGL和牧羊人V3/N332的成熟 和IOMA类的bNAbs，比约克曼博士提出了一个与努森茨韦格博士高度合作的项目，以(1) 解决IGL-免疫原复合体的结构问题，以辅助基于结构的免疫原设计和文库 筛选免疫原，(2)采用结构设计结合文库筛选进行鉴定 高亲和力结合V3/N332 IGL的SOSIP三聚体，(3)使用结构信息指导 酵母展示文库以寻找与IOMA IGL高亲和力结合的稀有变体，(4)结合AIMS的结果 2和3创造基于SOSIP的免疫原，结合两种bNAbs的IGL，并在野生型小鼠身上进行评估 Nussenzweig博士生产的携带生殖系回复版本的IOMA和10-1074的小鼠。这些 将使用来自新结构、图书馆屏幕和通过以下方式分离的抗体的屏幕的信息重复AIMS Nussenzweig博士来自HIV幼稚的个体和顺序免疫的动物。

Proj 2: Design and screening for immunogens to efficiently elicit anti-HIV-1 bNAbs PI: Pamela J. Bjorkman An effective HIV vaccine likely requires induction of Abs against HIV-1 Env that neutralize across the majority of circulating viral strains (broadly neutralizing antibodies; bNAbs). Because administered bNAbs are protective against HIV-1 infection in animal models, it is widely believed that a vaccine that elicits bNAbs would prevent infection. The fact that vaccine efforts have not yet succeeded preventing HIV-1 infection and/or eliciting bNAbs may relate to the observation that inferred germline (iGL) forms of bNAbs only rarely bind to Env proteins that are the targets of bNAbs. The germline targeting approach to vaccine design involves engineering an iGL-binding Env protein that preferentially activates bNAb precursors and selects productive somatic hypermutations (SHMs) during affinity maturation. Resulting memory B cells are then boosted by sequential immunogens to shepherd bNAb production by selecting additional productive SHMs. Drs. Bjorkman and Nussenzweig propose to apply this approach to target two classes of HIV-1 bNAb: 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, are commonly found in HIV-infected individuals who develop bNAbs, and immunogen studies will be complementary to human clinical trials evaluating passive delivery of the V3/N332 bNAb 10-1074 to HIV-1–infected patients, (ii) IOMA's relatively low number of SHMs 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 by the recent structure of a natively-glycosylated Env trimer bound to the V3/N332 bNAb 10-1074 and to IOMA. With the goal of creating SOSIP-based Env trimers to target iGLs and shepherd maturation of V3/N332 and IOMA-like bNAbs, Dr. Bjorkman proposes a highly collaborative project with Dr. Nussenzweig to (1) Solve structures of iGL–immunogen complexes to aid in structure-based immunogen design and library screens to select immunogens, (2) Use structure-based design combined with library screening to identify SOSIP 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 with high affinity, (4) Combine results from Aims 2 and 3 to create SOSIP-based immunogens that bind iGLs of both bNAbs and evaluate them in wildtype mice and in mice produced by Dr. Nussenzweig to carry germline-reverted versions of IOMA and 10-1074. These aims will be repeated using information from new structures, library screens, and screens for Abs isolated by Dr. Nussenzweig from HIV-naïve individuals and from sequentially-immunized animals.