Designing and optimizing candidate HIV vaccines and boosting protocols

摘要 HIV-1疫苗研究的一个主要目标是设计能够广泛诱导 结合病毒包膜糖蛋白（Env）的中和抗体（bnAb）。虽然许多艾滋病毒 已经从慢性感染的患者中分离出bnAb，通过免疫接种来提高bnAb已经被证明是有效的。 难主要问题似乎是（1）bnAb表位是亚显性的，因此 反应必须以这样一种方式启动和加强，以避免脱靶反应和有利于 （2）大多数形式的Env与未突变的bnAb前体结合较差， bnAb反应通常没有适当地引发，（3）我们不知道如何最好地 一旦引发产生bnAb，则增强反应，所述bnAb通常具有不寻常量的体细胞免疫应答。 突变在这个建议中，我们通过研究bnAb中的工程免疫原来解决这些问题 敲入老鼠 我们专注于两类bnAb，VRC 01和PGT 130，我们预测它们将很容易通过 使用适当工程化的免疫原在人类中进行疫苗接种。VRC 01是 识别CD 4结合位点（CD 4 bs）和PGT 130的一类是一类 结合Env上的V3环和甘露糖片的聚糖依赖性bnAb。两种抗体类别 已在许多HIV感染者中描述，并且特别有效和广泛 这表明能够引发这种抗体的疫苗将在相对低的抗体水平下提供保护， 浓度的 我们先前已经产生了携带具有生殖系回复的（gl）-VRC 01的B细胞的小鼠 免疫球蛋白重链（H）和轻链（L），在这里，我们建议产生新的基因敲入小鼠 携带gl-PGT 130 H-和L-链基因。小鼠表达了B细胞受体， 触发并成熟以生成VRC 01或PGT 130类bnAb，并将用于研究 免疫原和免疫策略。对于引发，我们将使用现有的种系靶向 我们将产生靶向gl-VRC 01的新型工程化免疫原， PGT 130和。为了加强免疫，我们将测试一系列工程和天然免疫原， 增强bnAb成熟的中间和最终步骤。 这项研究将测试我们的生殖细胞靶向方法的通用性，发现新的疫苗， 候选人，并教我们如何最大限度地发挥亚显性抗病毒反应， 为人类疫苗接种策略提供信息。

Abstract A major goal of HIV-1 vaccine research is the design of immunogens capable of inducing broadly neutralizing antibodies (bnAbs) that bind to the viral envelope glycoprotein (Env). While many HIV bnAbs have been isolated from chronically infected patients, raising bnAbs by immunization has been difficult. The principal problems appear to be (1) that bnAb epitopes are sub-dominant and so the response must be primed and boosted in such a way as to avoid off-target responses and favor the desired specificities, (2) that most forms of Env bind poorly to unmutated precursors of bnAbs so that bnAb responses are not typically primed appropriately and (3) we do not understand how best to boost responses once primed to yield bnAbs that typically have an unusual amount of somatic mutation. In this proposal, we address these problems by study of engineered immunogens in bnAb knockin mice. We focus on two classes of bnAbs, VRC01 and PGT130, which we predict will be readily raised by vaccination in humans using appropriately engineered immunogens. VRC01 is the prototype bnAb of a class that recognizes the CD4 binding site (CD4bs) and PGT130 is a representative of a class of glycan-dependent bnAbs that bind the V3 loop and mannose patch on Env. Both antibody classes have been described in many HIV infected individuals and are particularly potent and broad suggesting that a vaccine able to elicit such Abs would provide protection at relatively low Ab concentrations. We have previously generated mice engineered to carry B cells with germline reverted (gl)-VRC01 immunoglobulin heavy (H) and light (L)-chains, and here we propose to generated new knock-in mice carrying gl-PGT130 H- and L-chain genes. The mice express the B cell receptors that should be triggered and matured to generate VRC01 or PGT130 class bnAbs and will be used to investigate immunogens and immunization strategies. For priming, we will use existing germline-targeting immunogens reactive to gl-VRC01 and we will generate novel engineered immunogens targeting gl- PGT130 and. For boosting we will test a range of engineered and natural immunogens to focus and enhance intermediate and final steps in bnAb maturation. This study will test the generality of our germline-targeting approach, discover new vaccine candidates, and teach us lessons on how to maximize subdominant anti-viral responses that should inform human vaccination strategies in general.