Lymphocyte homeostastis & regulation during aging

B细胞亚群的大小、组成和动态随着年龄的变化而变化，表明B细胞发生了变化 动态平衡和选择性。BLyS及其受体在B细胞动态平衡中起着核心作用。 因此，我们假设BLyS介导的体内平衡过程在老年人中受到干扰。 个体，导致塑造和维持外围设备的动态和选择性事件的变化 B细胞池。这些研究将探索BLyS介导的动态平衡过程之间的关系 B细胞的增龄相关变化。在目标1中，我们将确定与年龄相关的 B细胞亚群的改变和谱系的选择依赖于BLyS-BR3介导的过程。骨髓 不同年龄的A/WySnJ和A/J小鼠的B谱系亚群将被表征为 代表性、规模和流失率。此外，不成熟的、过渡的、 将在不同年龄的A/J和A/WySnJ小鼠中评估卵泡和MZ亚群。这些研究将 采用流感血凝素(HA)特异性反应的有限稀释和精细特异性分析， 以及CDR3长度分析。在目标2中，我们将确定延长的寿命是否 衰老小鼠成熟的B细胞反映了捕获BLyS-BR3信号的能力增强。的水平 BLyS结合和BLyS受体表达以及BLyS和APRIL的下游介体 信号，随着个体年龄的增长而遵循。我们将确定这些转变是否反映了选择与 通过相互骨髓嵌合体分析老年小鼠发育B细胞的内在特性。 我们将确定老年B细胞在领养方面是否享有相对于年轻B细胞的竞争优势 转移，以及这是否被外源性SLYS管理废除。在目标3中，我们将确定 是否与年龄相关的血清自身抗体的出现取决于BLyS介导的事件。 这一目的的实验还将使用A/WSNJ和A/J株进行比较。与年龄相关的 随后将出现ANA，负责ANA抗体形成的B系亚群将 确定了ANA产生的克隆类型，并对产生ANA的克隆类型进行了评估。此外，我们还将直接测试 针对自身反应特异性的过渡性选择是否通过克隆和 表达的VLVH对的分析。在目标1-3中，我们将确定动力学、选择 老年B细胞群体中和/或BLyS受体的表达反映了EBP降低的下游结果 输出，和奥尔曼博士一起。在目标4中，我们将确定操纵BLyS水平是否可以恢复 免疫后强健的B和T细胞反应。我们将检查免疫反应 用BLyS或BLyS对老年人和年轻人进行流感HA检测 受体激动剂可恢复高水平的HA特异性抗体，以及升高的HA特异性T细胞和B细胞 免疫后的频率。

The size, composition, and dynamics of B cell subsets change with age, indicating shifts B cell homeostasis and selection. BLyS and its receptors play a central role in B cell homeostasis. Consequently, we hypothesize that BLyS mediated homeostatic processes are perturbed in aged individuals, leading to alterations in the dynamic and selective events that shape and maintain peripheral B cell pools. These studies will probe the relationship between BLyS-mediated homeostatic processes and age-associated changes among B cells. In aim 1, we will determine whether age-associated shifts in B cell subsets and repertoire selection rely on BLyS-BR3 mediated processes. Marrow and splenic.B lineage subsets of A/WySnJ and A/J mice at various ages will be characterized for representation, magnitude and turnover rate. In addition, repertoire diversity of immature, transitional, follicular, and MZ subsets will be assessed in A/J and A/WySnJ mice at various ages. These studies will employ limiting dilution and fine specificity analyses of the influenza hemagglutinin (HA)-specific response, as well as CDR3 length analyses. In aim 2, we will determine whether the lengthened lifespan of mature B cells in aged mice reflects enhanced ability to capture BLyS-BR3 signals. The levels of BLyS binding and BLyS receptor expression, as well as downstream mediators of BLyS and APRIL signaling, be followed as individuals age. We will establish whether these shifts reflect selection versus an intrinsic property of developing B cells in aged mice through analysis of reciprocal bone marrow chimeras. We will determine whether aged B cells enjoy a competitive advantage over young B cells in adoptive transfer, and whether this is abrogated by exogenous SLyS administration. In aim 3, we will determine whether the age-associated appearance of serum autoantibodies relies on BLyS mediated events. The experiments in this aim will also use the A/WsnJ and A/J strains for comparison. Age-associated appearance of ANAs will be followed, the B lineage subsets responsible for ANA antibody formation will be identified, and the repertoires of ANA producing clonotypes assessed. In addition, we will directly test whether transitional selection against autoreactive specificities changes with age through cloning and analysis of expressed VLVH pairs. In aims 1 -3, we will determine whether shifts in kinetics, selection and/or BLyS receptor expression in aged B cell populations reflect downstream outcomes of reduced EBP output, with Dr. Allman. In aim 4, we will determine whether manipulation of BLyS levels can restore robust B and T cell responses following immunization. We will examine the immune response to influenza HA in aged and young individuals to determine whether pretreatment with BLyS or BLyS receptor agonists restore litres of HA-specific antibody, as well as elevated HA-specific T cell, and B cell frequencies following immunization.