Accelerating Malaria Vaccines with a Custom Preclinical Humanized Mouse Model Platform

项目摘要 2019年有2.29亿疟疾病例，导致40.9万人死亡；有效疫苗 是全球卫生优先事项。能够预测人类免疫反应的动物模型 是疫苗临床前试验的重要组成部分。这项建议的主要目标是 将巴蒂斯塔实验室的技术创新应用于B细胞移植小鼠的快速生成 人类B细胞受体(BCR)为疟疾免疫原筛选和 发展。针对感染性子孢子阶段的疫苗可能会抑制这种建立 临床疟疾，子孢子表面被环子孢子蛋白密集覆盖 (CSP)；目前最先进的人体试验疫苗显示了这种蛋白质的区域，我们 打算使用我们的鼠标平台来提高他们的针对性。对于目标1，我们将使用现有的 小鼠模型，表达推测的有效单抗的种系版本 (MAb)目前正在进行临床试验，Cis43。使用免疫聚焦方法，提出了一种 CSP N-端与中心重复区之间的保守连接表位 不仅概括了这一有效单抗的个体发育过程，而且还引发了变异 在疟疾中更有效的抗体挑战实验。我们打算挖深矿 这个有效的平台通过可变长度的连接表位多肽免疫1) 确定疫苗中最有希望的候选结合表位免疫原 设计和2)鉴定具有潜在临床应用的保护性成熟抗体。在我们的模型中，B 携带人源化BCR的细胞被滴定到低水平，以模拟人类的生理条件。 对于目标2，我们将使用我们开发的全长和部分CSP探针来表征 我们的小鼠模型，结合单细胞测序，探索前体细胞的频率 人类的B细胞。我们将使用这些数字来提高我们鼠标平台的精度， 将人源化细胞滴定到更精确的水平。最后，在目标3中，我们将采用这一点 通过创建一系列新的小鼠来免疫聚焦CSP蛋白的其他区域 表达CSP其他亚区的人抗体前体序列。我们会 利用这一小鼠平台研究由不同节段组成的多肽的免疫原性 CSP蛋白，目的是识别理想的表位或表位组合，以诱导 强大的免疫反应。我们将通过移动多株Ki B细胞来增强我们的模型 到同一宿主，以尝试针对人源化B细胞的“微型曲目”的免疫原。通过创建 这些针对疟疾的新的精确平台，我们打算减少验证潜力所需的时间 候选疫苗。

Project Abstract There were 229 million cases of malaria in 2019, leading to 409,000 deaths; effective vaccines are a global health priority. Animal models capable of prefiguring the human immune response are a vital component of the preclinical testing of vaccines. The major goal of this proposal is to apply the Batista lab's technical innovations in the rapid generation of mice with B cells bearing human B cell receptors (BCRs) to create new platforms for malaria immunogen screening and development. Vaccines targeting the infectious sporozoite stage could inhibit the establishment of clinical malaria, and sporozoite surfaces are densely covered by circumsporozoite protein (CSP); the most advanced current vaccines in human trials display regions of this protein, and we intend to use our mouse platforms to improve their targeting. For Aim 1, we will use our existing mouse model, which expresses the inferred germline version of a potent monoclonal antibody (mAb) currently in clinical trials, CIS43. Using an immunofocused approach, presenting a conserved junctional epitope between the N-terminus and the central repeat region of CSP, we have not only recapitulated the ontogeny of this potent mAb, but have also elicited variant antibodies that are even more effective in malaria challenge experiments. We intend to deep mine this effective platform with immunizations by variable-length junctional epitope peptides to 1) identify the most promising candidate junctional epitope immunogens for inclusion in vaccine design and 2) identify protective matured antibodies with potential clinical utility. In our models, B cells bearing humanized BCRs are titrated to low levels to mimic human physiological conditions. For Aim 2, we will use the CSP full-length and partial probes we have developed for characterizing our mouse models, in tandem with single-cell sequencing, to explore the frequencies of precursor B cells in humans. We will use these numbers to improve the precision of our mouse platform, titrating the humanized cells to more exactingly accurate levels. Finally, in Aim 3, we will take this immunofocusing approach to other regions of the CSP protein by creating a new series of mice expressing the precursor sequences of human antibodies to other subdomains of CSP. We will use this mouse platform to study the immunogenicity of peptides consisting of various sections of the CSP protein, with the goal of identifying the ideal epitope, or combination of epitopes, to elicit robust immune responses. We will enhance our models by moving multiple strains of KI B cells to the same host to try immunogens against “mini-repertoires” of humanized B cells. By creating these new precision platforms for malaria, we intend to cut the time needed to validate potential vaccine candidates.