AGED MICROENVIRONMENT EFFECT ON T CELL EXPANSION

衰老微环境对 T 细胞增殖的影响

• 批准号: 6372390
• 负责人: WILLIAM T LEE
• 金额: $ 16.28万
• 依托单位: WADSWORTH CENTER
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2003-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6372390
• 关键词: B lymphocyte; aging; antigen presenting cell; cell cell interaction; flow cytometry; genetically modified animals; helper T lymphocyte; immunologic memory; immunosenescence; interleukin 1; interleukin 6; laboratory mouse; leukocyte activation /transformation; neutralizing antibody; ovalbumin; passive immunization; tissue /cell culture; tumor necrosis factor alpha

As aging is associated with a decline in protective immunity to foreign pathogens, understanding how the immune system changes with age is important for the design of both therapeutic interventions and vaccines to treat infectious diseases in the elderly. Since CD4 T cells play a central role in mediating the response to foreign antigens, many studies have directly compared the function of young and aged CD4 T cells. However, during immune responses CD4 T cells do not function independently of the rest of the immune system, rather, they interact with other cell types and are exposed to different cytokines. The objective of this proposal is to study the context in which CD4 cells are activated, that is, the effect of the aged microenvironment on antigen-specific CD4 T cell responses. An adoptive transfer model will be employed in which CD4 T cell responses can be monitored in vivo. By transferring antigen-specific T cells into young and aged mice, the effect of the different microenvironments in which CD4 T cells function can be directly compared. By characterizing the transferred T cell population at different stages of the response, it will be possible to determine how the aged microenvironment effects T cell activation and expansion, activation- induced cell death, and memory T cell development. T cells from DO11.10 T cell receptor transgenic mice specifically recognize a peptide derived from ovalbumin (OVA) in the context of self-MHC class II molecules. These T cells can be adoptively transferred into BALB/c mice, and following immunization with OVA, the response of these T cells can be monitored. The specific aims of this proposal are: (1) To characterize the rate and magnitude of CD4 T cell expansion in young and aged animals. Flow cytometry will be used to enumerate the number of OVA-responsive cells after immunization. Further, differences in the number of recovered T cells in young versus aged recipients will be related to the degree of cell growth or to levels of cell death. (2) To determine the role of antigen presenting cells in the aged and young microenvironment. The primary focus will be on young versus aged B cells and their ability to modulate T cell activation in vitro and in vivo. (3) To determine the role of pro-inflammatory cytokines in modulating activated T cell numbers in aged and young mice. Age-related changes in the basal and induced levels of these cytokines will be determined. Further, the effects of these cytokines on the in vivo CD4 T cell response will be determined by administering neutralizing antibodies in conjunction with adoptive transfer of T cells. These studies will further the understanding of the physiological basis of age-related changes that occur in the immune system, and may help explain the decline in protective immunity in the elderly.

由于衰老与对外来病原体的保护性免疫的下降有关，因此了解免疫系统随着年龄的变化而对设计治疗干预措施和疫苗的设计很重要，以治疗老年人的传染病。 由于CD4 T细胞在介导对外国抗原的反应中起着核心作用，因此许多研究已直接比较了年轻和老化的CD4 T细胞的功能。但是，在免疫反应过程中，CD4 T细胞与免疫系统的其余部分不独立起作用，而是与其他细胞类型相互作用，并暴露于不同的细胞因子。该建议的目的是研究激活CD4细胞的背景，即老化微环境对抗原特异性CD4 T细胞反应的影响。 将采用一种收养转移模型，在该模型中可以在体内监测CD4 T细胞响应。 通过将抗原特异性T细胞转移到年轻小鼠和老年小鼠中，可以直接比较CD4 T细胞功能的不同微环境的影响。通过表征在反应的不同阶段转移的T细胞种群，可以确定老化的微环境如何影响T细胞激活和扩张，激活诱导的细胞死亡以及记忆T细胞的发育。来自DO11.10 T细胞受体转基因小鼠的T细胞特异性地识别自MHC II类分子的背景下源自卵蛋白（OVA）的肽。可以将这些T细胞转移到BALB/C小鼠中，并在用OVA免疫后，可以监测这些T细胞的响应。该提案的具体目的是：（1）表征年轻动物和老年动物中CD4 T细胞膨胀的速率和幅度。 流式细胞仪将用于列举免疫后的OVA反应性细胞数量。此外，年轻人与老年接受者中回收T细胞数量的差异将与细胞生长程度或细胞死亡水平有关。 （2）确定抗原呈递细胞在老化和年轻微环境中的作用。主要的重点将放在年轻的B细胞和年龄的B细胞上及其在体外和体内调节T细胞激活的能力。 （3）确定促炎性细胞因子在调节年龄和幼鼠中活化的T细胞数量中的作用。将确定这些细胞因子的基础和诱导水平与年龄相关的变化。此外，这些细胞因子对体内CD4 T细胞反应的影响将通过与T细胞的过继转移结合施用中和抗体来确定。这些研究将进一步理解免疫系统中与年龄相关的变化的生理基础，并可能有助于解释老年人保护性免疫的下降。