Improved Humanized Mouse Models for Vaccine Development

描述（由申请人提供）：本项目的目的是提高“人源化”小鼠的免疫功能，以便为测试HIV/AIDS候选疫苗提供更好的模型。在过去的20年里，在将人细胞转移到免疫缺陷小鼠后产生人免疫功能的技术已经逐渐改进。该项目从目前最好的模型开始，将人CD 34阳性造血祖细胞转移到Rag-2和IL-2受体共同γ链基因遗传破坏的小鼠中，并系统地评估改善该模型中观察到的许多移植人B淋巴细胞功能的策略。该项目特别关注人类B细胞的两个亚群，负责“天然抗体”的B1亚群和负责碳水化合物抗原抗体的边缘区（MZ）B2亚群，因为我们正在评估靶向HIV-1包膜刺突上的碳水化合物的糖缀合物疫苗（由Dennis Burton及其合作者生产）。最近在理解B1和MZ B细胞分化方面的进展为提供支持基质细胞和分化因子提供了基本原理，这些细胞和分化因子应该增强这些人B细胞的存活和功能。在当前人源化小鼠模型中识别的缺陷，即在小鼠上皮细胞上阳性选择的人滤泡树突细胞和人T细胞的缺乏，将通过额外的细胞移植来修复。一种更适合替换缺失的支持细胞的“人工淋巴结”方法也将用于更快速地评估哪种细胞类型对完全功能性免疫应答至关重要。该研究提案直接响应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免受靶向包膜蛋白组分的常规抗体的攻击。该项目具体目标的成功实施将产生一种人源化小鼠模型，能够快速筛选多种HIV-1候选疫苗的免疫原性和抗HIV-1感染的保护作用。这将加速疫苗的开发，减少对灵长类动物攻击模型的依赖。开发一种有效的疫苗来预防艾滋病毒/艾滋病有许多挑战，更有效地应对这些挑战的一种方法是开发一种小动物模型系统，准确地反映人类对候选疫苗的免疫反应。经过多年的努力，这个目标似乎已经接近。这项提案将试图解决“人源化小鼠”中剩下的几个问题，并利用它们来测试一种新的艾滋病疫苗，这种疫苗用病毒的糖基修饰。

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.