CELL CD86 AND CYTOKINE RESPONSIVENESS

描述(摘自申请者的摘要)：我们的长期目标 研究是为了更好地理解 交感神经递质去甲肾上腺素对免疫系统的调节作用 功能。在我们的实验室里，最近有两项重要发现 在体外，需要在体内进行积极的研究。第一，β-2肾上腺素能 去甲肾上腺素或选择性激动剂对B细胞β2受体的刺激作用 体外诱导Th2/IL-4依赖的IgG1量增加，但不 Thl/干扰素-γ依赖的IgG2a，通过一种涉及B增加的机制 细胞对IL-4的反应性以及B细胞水平的增加 细胞相关CD86(B7-2)的表达和信号转导。第二，IgG2a生产 在体外，当刺激TH1细胞上的β-2AR增加时 IgG2a促进细胞因子干扰素-γ的产生水平。另外， Th2/B细胞模型系统中任一Th1/B细胞体内去甲肾上腺素的研究 抑制血清IgG2a和IgG1水平，但抑制脾滤泡 Th2/B细胞模型中的扩增和生发中心形成受到影响 仅限系统。我们建议将目前的研究重点放在解决是否 最初在体外取得的关键发现可以在体内得到验证，也可以 确定B细胞中的CD86信号是否影响B细胞的反应性 细胞对IF-4的作用，但对干扰素-γ的作用不同。我们建议检验一个两部分的假设。 首先，去甲肾上腺素通过与β-2受体结合来增加体内的IgG1水平 B细胞，以增加CD86的表达水平，并在B细胞中发出信号。 第二，去甲肾上腺素通过与β-2受体结合，增加体内IgG2a水平 在Thl细胞上增加产生的干扰素-γ水平，而不影响 B细胞对干扰素-γ的反应性水平。以确定Beta-2 AR和 CD86刺激使B细胞对Th2介导的信号有反应，但不是 对于Th-1介导的信号，将使用体内模型系统，其中SCID 小鼠保持NE完好或NE耗尽，然后用 β-2AR(Neg)-Th2细胞或β-2AR(pos或neg)-Thl细胞和β-2 AR(pos或neg)-B细胞。在重建后，这些小鼠将被注射 各种免疫刺激剂和药理激动剂和拮抗剂。这个 拟议研究的意义在于，它将帮助我们理解 可能调节IgG1和IgG2a水平的内源性稳态机制 中和或溶解传染性疾病所必需的免疫力 生物体，以及这种动态平衡的失调 其发病机制可能与IgG1vS. IgG2a介导的免疫和神经系统疾病。

DESCRIPTION(adapted from applicant's abstract): The long-term objective of our research is to achieve a better understanding of the mechanism by which the sympathetic neurotransmitter norepinephrine (NE) regulates immune system function. In our laboratory, two key discoveries have been made recently in vitro and need to be pursued aggressively in vivo. First, beta-2-adrenergic receptor (beta-2 AR) stimulation on a B cell by NE or a selective agonist in vitro induces an increase in the amount of Th2/IL-4-dependent IgG1, but not Thl/IFN-gamma-dependent IgG2a, via a mechanism that involves an increase in B cell responsiveness to IL-4, as well as an increase in the level of B cell-associated CD86 (B7-2) expression and signaling. Second, IgG2a production in vitro increases when the beta-2 AR on a TH1 cell is stimulated to increase the level of production of the IgG2a-promoting cytokine IFN-gamma. Also, depletion of NE in either a Th1/B cell of Th2/B cell model system in vivo inhibits the level of both serum IgG2a and IgG1, but splenic follicular expansion and germinal center formation are affected in the Th2/B cell model system only. We propose to focus the present study on resolving whether or not the initial key discoveries made in vitro can be validated in vivo, as well as to determine if CD86 signaling in a B cell affects the responsiveness of a B cell to IF-4, but not to IFN-gamma. We propose to test a two part hypothesis. First, NE increases the level of IgG1 in vivo by binding to the beta-2 AR on a B cell to increase the level of CD86 expression on, and signaling in, a B cell. And second, NE increases the level of IgG2a in vivo by binding to the beta-2 AR on a Thl cell to increase the level of IFN-gamma produced, without affecting the level of B cell responsiveness to IFN-gamma. To determine if beta-2 AR and CD86 stimulation render the B cell responsive to Th2-mediated signals, but not to Th-1 mediated signals, an in vivo model system will be used in which a scid mouse is kept NE-intact or is NE-depleted before being reconstituted with either beta-2 AR(neg)-Th2 cells or beta-2 AR(pos or neg)-Thl cells and beta-2 AR(pos or neg)-B cells. After reconstitution, these mice will be administered various immunologic stimuli and pharmacologic agonists and antagonists. The significance of the proposed research is that it will help us to understand an endogenous homeostatic mechanism that may regulate the level of IgG1 and IgG2a immunity that is necessary for either the neutralization or lysis of infectious organisms, respectively, as well as how dysregulation of this homeostatic mechanism may contribute to the development and progression of IgG1-vs. IgG2a-mediated diseases of the immune and nervous system.