Accelerating Malaria Vaccines with a Custom Preclinical Humanized Mouse Model Platform

项目摘要 2019年有2.29亿例疟疾病例，导致40.9万人死亡;有效的疫苗 是全球健康的优先事项。能够预测人类免疫反应的动物模型 是疫苗临床前测试的重要组成部分。该提案的主要目标是 将巴蒂斯塔实验室的技术创新应用于携带B细胞的小鼠的快速繁殖， 人类B细胞受体（BCR），为疟疾免疫原筛选创造新平台， 发展针对感染性子孢子阶段的疫苗可以抑制 的临床疟疾，和孢子表面密集覆盖环子孢子蛋白 (CSP)目前最先进的疫苗在人体试验中显示这种蛋白质的区域，我们 打算使用我们的鼠标平台来提高他们的目标。对于目标1，我们将使用现有的 小鼠模型，其表达推断的有效单克隆抗体的生殖系版本 (mAb)目前在临床试验中，CIS 43。使用免疫聚焦的方法，提出了一个 CSP的N-末端和中心重复区之间的保守连接表位，我们 不仅概括了这种强效mAb的个体发育，而且还引起了变异 在疟疾挑战实验中更有效的抗体。我们打算挖深矿井 该有效平台通过可变长度的连接表位肽免疫，以1） 鉴定最有希望的候选接合表位免疫原以纳入疫苗中 设计和2）鉴定具有潜在临床效用的保护性成熟抗体。在我们的模型中，B 将携带人源化BCR的细胞滴定至低水平以模拟人生理条件。 对于目标2，我们将使用我们开发的CSP全长和部分探针进行表征 我们的小鼠模型，与单细胞测序串联，以探索前体的频率 人体内的B细胞。我们将使用这些数字来提高鼠标平台的精度， 将人源化细胞滴定到更精确的水平。最后，在目标3中， 通过建立一系列新的小鼠， 表达针对CSP其它亚结构域的人抗体的前体序列。我们将 使用这个小鼠平台来研究由各种不同片段组成的肽的免疫原性， CSP蛋白，其目标是鉴定理想的表位或表位组合，以引发 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 对同一宿主进行免疫原试验，以对抗人源化B细胞的“微型库”。通过创建 这些新的疟疾精确平台，我们打算缩短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.