McGillis J P, Hall N R, Goldstein A L
J Immunol. 1983 Jul;131(1):148-51.
Studies by many investigators have demonstrated that the immune system is subject to regular circadian fluctuation. Some rhythms that have been reported include circadian changes in components of the immune system, e.g., lymphocytes, and circadian variation in primary and secondary immune responsiveness. The observation that many of these rhythms are inversely correlated to the glucocorticoid rhythm has led to the suggestion that fluctuations in the immune system may be a result of the glucocorticoid circadian rhythm. This study was designed to see if thymosin-alpha 1 (Tsn-alpha 1), a 28-amino acid polypeptide isolated from bovine thymus that has been reported to influence thymocyte differentiation, might follow a circadian rhythm, and thus play a role in the periodicity of the immune system. In these experiments, groups of 10 C57BL/6 or Swiss Webster mice were sacrificed at 4- or 6-hr intervals over a 24-hr period. Serum Tsn-alpha 1 and corticosterone levels were determined by radioimmunoassay. Results from the first experiment showed that Tsn-alpha 1 undergoes a circadian rhythm (p less than 0.001) with an acrophase (time of peak levels) 1.5 hr after the onset of light, and an amplitude (amount of maximum variation from the 24-hr mean) of 0.493 ng/ml Tsn-alpha 1-like immunoreactivity. These results were confirmed in an experiment in which the animals were placed on a reversed light cycle. In a separate experiment, the Tsn-alpha 1 circadian rhythm persisted in mice thymectomized 6 mo. earlier. In this latter experiment, a significant increase in the amplitude of the corticosterone rhythm in the thymectomized relative to sham-operated controls was also observed. Although these experiments do not imply casuality, it is interesting that the time of peak Tsn-alpha 1 levels can be correlated with the time of optimal immune function.
许多研究者的研究表明，免疫系统会受到规律的昼夜节律波动影响。已报道的一些节律包括免疫系统组成成分（如淋巴细胞）的昼夜变化，以及初次和二次免疫反应性的昼夜变化。许多这些节律与糖皮质激素节律呈负相关的观察结果提示，免疫系统的波动可能是糖皮质激素昼夜节律的结果。本研究旨在观察胸腺素α1（Tsn-α1），一种从牛胸腺中分离出的28个氨基酸的多肽，据报道可影响胸腺细胞分化，是否会遵循昼夜节律，从而在免疫系统的周期性中发挥作用。在这些实验中，将10只C57BL/6或瑞士韦伯斯特小鼠分为一组，在24小时内每隔4或6小时处死一批。通过放射免疫测定法测定血清Tsn-α1和皮质酮水平。第一个实验的结果表明，Tsn-α1呈现昼夜节律（p<0.001），其高峰期（峰值水平时间）在光照开始后1.5小时，振幅（相对于24小时平均值的最大变化量）为0.493 ng/ml Tsn-α1样免疫反应性。这些结果在将动物置于反向光照周期的实验中得到了证实。在另一个实验中，Tsn-α1的昼夜节律在6个月前接受胸腺切除术的小鼠中持续存在。在后者的实验中，还观察到与假手术对照组相比，胸腺切除小鼠的皮质酮节律振幅显著增加。尽管这些实验并不意味着因果关系，但有趣的是，Tsn-α1水平的峰值时间与最佳免疫功能时间相关。
