Role of WASP and N-WASP in B cell maturation, homing and function

Wiskott-Aldrich综合征（WAS）是一种严重的免疫缺陷，由WASP突变引起， 属于控制从头肌动蛋白成核的蛋白质家族。目前尚不清楚体液免疫缺陷是否 在WASP患者和WASP-/-小鼠中观察到免疫反应反映了WASP对B细胞的B细胞内在作用 分化和功能，以及N-WASP是否可能在这些过程中发挥补偿作用。 我们将检验WASP和/或N-WASP表达缺乏影响B淋巴细胞的假设。 成熟、归巢和以细胞内在方式发挥功能。 为此，我们将研究人体内WASP+和WASP-细胞之间的体内竞争模型， 小鼠我们还将开发条件性敲除模型，其中WASP和/或N-WASP的表达是 在B淋巴细胞中消融。具体而言，我们将： 1)分析WASP在B细胞发育和成熟中的作用，通过体内实验分析WASP对B细胞发育和成熟的影响。 在小鼠和人类中的竞争模型。 将在WASP+和WASP-细胞中分析记忆和幼稚B细胞的比例。 XLT。我们还将分析WASP在老年中枢反应和体细胞超变中的作用， 在WASP+/-小鼠和其中N-WASP表达在B细胞中缺失的WASP+/-小鼠中进行免疫。 2)检验WASP和/或N-WASP的B细胞特异性缺乏影响B细胞成熟的假设， 归巢和体内功能。 为此，我们将开发一种B细胞中WASP缺乏的条件模型。我们将测试 B细胞特异性缺乏小鼠外周血B细胞的分布、归巢及免疫应答 WASP和/或N-WASP。我们将分析具有B细胞特异性WASP缺陷的小鼠对以下疾病的易感性： 入侵S.肺炎感染，并探讨IgM记忆B细胞的数量可能存在的缺陷， WASP基因突变的患者。 3)检验WASP和/或N-WASP的B细胞特异性缺乏影响体外B细胞功能的假设。 为了这个目的，将在体外研究来自以下的B细胞中的趋化性、活化和类别转换重组： B细胞特异性缺乏WASP和/或N-WASP的小鼠。 我们预计，该项目的结果将使我们更好地了解WAS的生物学， 对于开发WAS的新治疗形式，包括基因治疗，具有重要意义。

The Wiskott-Aldrich syndrome (WAS) is a severe immune deficiency, caused by mutations of WASP, that belongs to a family of proteins that control de novo actin nucleation. It is unclear whether defects in humoral immunity observed in patients with WAS and in WASP-/- mice reflect a B-cell intrinsic role of WASP for B cell differentiation, and function, and whether N-WASP may play a compensatory role in these processes. We will test the hypothesis that lack of expression of WASP and/or N-WASP affects B lymphocyte maturation, homing and function in a cell-intrinsic fashion. To this purpose, we will study in vivo competition models between WASP+ and WASP- cells in humans and mice. We will also develop conditional knock-out models in which expression of WASP and/or N-WASP is ablated in B lymphocytes. Specifically, we will: 1) analyze the role of WASP in B cell development and maturation, through the analysis of in vivo competition models both in mice and in humans. The proportion of memory and naive B cells will be analyzed among WASP+ and WASP- cells in carriers of XLT. We will also analyze the role of WASP in germinal center reaction and somatic hypermutation following immunization in WASP+/- mice and in WASP+/- mice in which expression of N-WASP is deleted in B cells. 2) test the hypothesis that the B-cell specific lack of WASP and/or N-WASP affects B cell maturation, homing and function in vivo. To this purpose, we will develop a conditional model of WASP deficiency in B cells. We will test the peripheral distribution and homing of B cells, and response to immunization in mice with B-cell specific lack of WASP and/or N-WASP. We will analyze susceptibility of mice with B-cell-specific deficiency of WASP to invasive S. pneumoniae infection, and explore possible defects in the number of IgM memory B cells in patients with WASP gene mutations. 3) test the hypothesis that the B-cell specific lack of WASP and/or N-WASP affects B cell function in vitro. To this purpose, chemotaxis, activation and class-switch recombination will be studied in vitro in B cells from mice with B-cell specific lack of WASP and/or N-WASP. We anticipate that the results of .this project will allow a better understanding of the biology of WAS, and will be important for development of novel forms of treatment of WAS, including gene therapy.