Lymphocyte homeostastis & regulation during aging

随着年龄的增长，B细胞亚群的大小、组成和动态发生变化，表明B细胞亚群的变化与年龄有关。 自我平衡和选择BLyS及其受体在B细胞稳态中起着重要作用。 因此，我们假设BLyS介导的稳态过程在老年人中受到干扰， 个体，导致动态和选择性事件的改变，这些事件塑造和维持了周边 B细胞池。这些研究将探讨BLyS介导的稳态过程之间的关系， 以及B细胞中与年龄相关的变化。在目标1中，我们将确定是否与年龄相关 B细胞亚群的变化和库选择依赖于BLyS-BR 3介导的过程。骨髓 将表征不同年龄的A/WySnJ和A/J小鼠的B谱系亚群， 代表性、规模和周转率。此外，剧目多样性的不成熟，过渡， 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CDR 3长度分析。在目标2中，我们将确定延长的寿命是否 老年小鼠中的成熟B细胞反映了增强的捕获BLyS-BR 3信号的能力。水平 BLyS结合和BLyS受体表达，以及BLyS和APRIL的下游介质 信号，随着个体年龄的增长。我们将确定这些变化是否反映了选择， 从骨髓嵌合体分析老年小鼠发育中B细胞内在特性 我们将确定老化的B细胞在过继性中是否比年轻的B细胞具有竞争优势 转移，以及这是否被外源性SLyS施用所废除。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依赖于BLyS介导的事件。 在此目的的实验中，还将使用A/WsnJ和A/J菌株进行比较。年龄相关 ANA出现后，负责ANA抗体形成的B谱系亚群将 鉴定，并评估ANA产生克隆型的库。此外，我们将直接测试 通过克隆，针对自身反应特异性的过渡性选择是否随年龄而改变， 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细胞群体中的BLyS和/或BLyS受体表达反映了EBP降低的下游结果 输出，与博士奥尔曼。在目标4中，我们将确定BLyS水平的操纵是否可以恢复 免疫后的强B和T细胞应答。我们将检查免疫反应， 老年人和年轻人中的流感HA，以确定是否使用BLyS或BLyS进行预处理 受体激动剂恢复HA特异性抗体的升数，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.