MECHANISM OF THYMIC ATROPHY INDUCED BY ALCOHOL

描述（由申请人提供）： 饮酒会抑制免疫功能。 酗酒者感染性和自身免疫性疾病的发病率增加。 酒精消耗诱导胸腺重量和细胞结构的损失，但潜在的生物学机制尚不清楚。 在初步实验中，酒精消耗加速胸腺萎缩和衰老。 饮酒显著增加了胸腺中的CD 4 + CD 8 + CD 25+亚群。 这些细胞也随着年龄的增长而增加。 这一建议的假设是，酒精消耗引起的胸腺萎缩是由于胸腺微环境的变化。 这些改变抑制胸腺T细胞的发育并增加CD 4 + CD 8 + CD 25+细胞的百分比。 这些细胞反过来又抑制胸腺细胞生长并加速胸腺萎缩。 因此，外周T细胞区室含有较少的初始T细胞。 记忆T细胞增加以补偿这种减少。 这种减少的新结果是T细胞介导的免疫功能下降。 将在雌性C57 BL/6小鼠中研究20% w/v酒精摄入对胸腺的影响。 具体目的是：1）确定饮酒小鼠胸腺微环境是否发生改变。 确定诱导CD 4 + CD 8 + CD 25+发育、分化和增殖的因素。 2)使用体外和体内模型系统表征CD 4 + CD 8 + CD 25+细胞群的生物学功能。 3)确定特定外周T细胞亚群的改变是否与胸腺CD 4 + CD 8 + CD 25+细胞的增加有关。 在目的1中，将通过RNA酶保护和ELISA测定来评估胸腺细胞因子表达。 采用半定量RT-PCR方法研究饮酒对重组激活基因表达的影响。 将通过BrdU标记和流式细胞术分析确定CD 4 + CD 8 + CD 25+的增殖状态。 在目标2中，将使用胸腺器官培养和SCID小鼠细胞转移实验，在体外和体内模型系统中检查CD 4 + CD 8 + CD 25+细胞群的生物学功能。 在目标3中，将研究酒精消耗对调节外周中的幼稚T细胞和记忆T细胞的影响。 本研究的长期目标是了解由大量饮酒引起的胸腺细胞结构丧失的机制，并确定这种作用的可逆性。

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.