MECHANISM OF THYMIC ATROPHY INDUCED BY ALCOHOL

描述(由申请人提供)： 饮酒会抑制免疫功能。酗酒者患传染病和自身免疫性疾病的几率增加。饮酒会导致胸腺重量和细胞密度下降，但其潜在的生物学机制尚不清楚。在初步实验中，饮酒加速了胸腺的萎缩和衰老。饮酒显著增加胸腺中的CD4+CD8+CD25+亚群。这些细胞也随着年龄的增长而增加。这一假设认为，饮酒导致的胸腺萎缩是由于胸腺微环境的变化。这些改变抑制了胸腺T细胞的发育，增加了CD4+CD8+CD25+细胞的百分比。这些细胞反过来抑制胸腺细胞的生长，加速胸腺萎缩。因此，外周T细胞室含有较少的原始T细胞。记忆T细胞增加以补偿这种减少。这种下降的新结果是T细胞介导的免疫功能下降。将在雌性C57BL/6小鼠身上研究20%w/v酒精摄入量对胸腺的影响。具体目的是：1)确定饮酒小鼠的胸腺微环境是否发生了变化。确定诱导CD4+CD8+CD25+发育、分化和增殖的因素。2)利用体外和体内模型系统研究CD4+CD8+CD25+细胞群的生物学功能。3)确定外周T细胞亚群的改变是否与胸腺中CD4+CD8+CD25+细胞的增加有关。在目标1中，胸腺细胞因子的表达将通过核糖核酸酶保护和酶联免疫吸附试验进行评估。半定量RT-PCR将用于研究饮酒对重组激活基因表达的影响。通过BrdU标记和流式细胞仪分析，确定CD4+CD8+CD25+细胞的增殖状态。目的2通过对SCID小鼠进行胸腺器官培养和细胞移植实验，在体外和体内模型系统中检测CD4+CD8+CD25+细胞群的生物学功能。目的3研究酒精对外周幼稚T细胞和记忆性T细胞的调节作用。这项研究的长期目标是了解高饮酒导致胸腺细胞丧失的机制，并确定这种影响的可逆性。

DESCRIPTION (provided by applicant): Alcohol consumption suppresses immune function. Alcoholics have an increased incidence of infectious and autoimmune diseases. Alcohol consumption induces loss in thymic weight and cellularity, but the underlying biological mechanism is unknown. In preliminary experiments alcohol consumption accelerated thymus atrophy and aging. Alcohol consumption dramatically increased the CD4+CD8+CD25+ subpopulation in the thymus. These cells were also increased with age., The hypothesis of this proposal is that the thymic atrophy from alcohol consumption is due to changes in the microenvironment of the thymus. These alterations inhibit the development of thymic T cells and increase the percentage of CD4+CD8+CD25+ cells. These cells in turn suppress thymocyte growth and accelerate thymic atrophy. Thus, the peripheral T cell compartment contains fewer naive T cells. The memory T cells increase to compensate for this decrease. The new result of this decrease is a decline in T cell- mediated immune function. The effects of 20% w/v alcohol consumption on the thymus will be studied in female C57BL/6 mice. The specific aims are: 1) Determine if the microenvironment of the thymus is altered in alcohol-consuming mice. Identify the factors that induce CD4+CD8+CD25+ development, differentiation and proliferation. 2) Characterize the biological functions of the CD4+CD8+CD25+ cell population using in vitro and in vivo model systems. 3) Determine if the alteration of specific peripheral T cell subpopulations is related to the increase in thymic CD4+CD8+CD25+ cells. In aim 1, thymic cytokine expression will be assessed by Rnase protection and ELISA assays. Semi-quantitative RT-PCR will be used to study the effect of alcohol consumption on expression of the recombination activating gene. The proliferative state of the CD4+CD8+CD25+ will be determined by BrdU labeling and flow cytometric analysis. In aim 2 the biological functions of the CD4+CD8+CD25+ cell population will be examined in vitro and in vivo model systems using thymic organ culture and cell transfer experiments into SCID mice. In aim 3 the effect of alcohol consumption to modulate naive T cells and memory T cells in the periphery will be studied. The long term objective of this research is to understand the mechanism underlying the loss in thymic cellularity induced by high alcohol consumption and to determine the reversibility of this effect.