Improved Humanized Mouse Models for Vaccine Development

描述(申请人提供)：该项目的目标是改善人源化小鼠的免疫功能，以便为测试艾滋病毒/艾滋病候选疫苗提供更好的模型。在过去的20年里，通过将人类细胞转移到免疫缺陷小鼠身上来产生人类免疫功能的技术已经逐步改进。该项目从目前最好的模型开始，将人CD34阳性的造血祖细胞转移到RAG-2和IL-2受体共同的伽马链基因遗传中断的小鼠中，并系统地评估了在该模型中观察到的许多移植的人类B淋巴细胞的功能改善策略。该项目特别关注人类B细胞的两个子集，B1子集负责“天然抗体”，边缘带(MZ)B2子集负责碳水化合物抗原抗体，因为我们正在评估针对HIV-1包膜尖峰上的碳水化合物的糖结合疫苗(由Dennis Burton和合作者生产)。最近对B1和MZ B细胞分化的了解的进展为提供支持基质细胞和分化因子提供了理论基础，这些分化因子应该增强这些人类B细胞的存活和功能。目前人源化小鼠模型中认识到的缺陷，即缺乏在小鼠上皮细胞上阳性选择的人滤泡树突状细胞和人T细胞，将通过额外的细胞移植来修复。一种更易于替换缺失的支持细胞的“人工淋巴结”方法也将被用来更快地评估哪种细胞类型对完全功能的免疫反应至关重要。这项研究提案直接响应RFA-AI-07-015，因为它试图表征B1和MZ B细胞对碳水化合物的反应，这些碳水化合物保护HIV-1免受针对包膜蛋白成分的传统抗体的攻击。项目特定目标的成功执行将产生一种人源化的小鼠模型，能够快速筛选多种艾滋病毒-1候选疫苗，既具有免疫原性，又能预防艾滋病毒-1感染。这将加快疫苗的开发，并减少对灵长类挑战模型的依赖。开发预防艾滋病毒/艾滋病的有效疫苗面临许多挑战，而更有效地应对这些挑战的方法之一是开发一种能够准确反映人类对候选疫苗的免疫反应的小动物模型系统。经过多年的努力，这一目标似乎即将实现。这项提议将试图解决“人源化小鼠”中仅存的几个问题，并用它们来测试一种新的艾滋病疫苗，该疫苗上装饰着来自病毒的糖基。

DESCRIPTION (provided by applicant): This goal of this project is to improve the immune function of "humanized" mice in order to provide a better model for testing candidate vaccines for HIV/AIDS. Over the past 20 years, techniques for generating human immune function following transfer of human cells to immunodeficient mice have gradually improved. This project begins with the best of the current models, transfer of human CD34-positive hematopoietic progenitor cells to mice with genetic disruption of Rag-2 and IL-2 receptor common gamma chain genes, and systematically evaluates strategies to improve the function of the many engrafted human B lymphocytes observed in this model. The project specifically focuses on two subsets of human B cells, the B1 subset responsible for "natural antibodies" and the marginal zone (MZ) B2 subset responsible for antibodies to carbohydrate antigens, because we are evaluating glycoconjugate vaccines (produced by Dennis Burton and collaborators) that target carbohydrates on the envelope spike of HIV-1. Recent advances in understanding the differentiation of B1 and MZ B cells provide the rationale for supplying supporting stromal cells and differentiation factors that should enhance the survival and function of these human B cells. The deficits recognized in the current humanized mouse model, absence of human follicular dendritic cells and human T cells that are positively selected on mouse epithelial cells, will be repaired by additional cell transplants. An "artificial lymph node" approach that is more amenable to replacing missing supporting cells will also be used to more rapidly evaluate which cell type is critical for fully functional immune responses. This research proposal is directly responsive to RFA-AI-07-015 in that it attempts to characterize B1 and MZ B cell responses to carbohydrates that shield HIV-1 from attack by conventional antibodies targeting protein components of the envelope. Successful execution of the project specific aims will result in a humanized mouse model capable of rapidly screening multiple HIV-1 candidate vaccines for both immunogenicity and protection against HIV-1 infection. This would speed vaccine development and reduce reliance on primate challenge models. There are many challenges to developing an effective vaccine to prevent HIV/AIDS, and one way to more effectively confront these challenges is to develop a small animal model system that accurately reflects the human immune response to candidate vaccines. After many years of work, that goal seems close. This proposal will attempt to fix the few remaining problems in "humanized mice", and use them to test a new AIDS vaccine decorated with sugar groups from the virus.