小鼠胸腺细胞发育过程中CD4+CD25+T细胞变化的体内外比较

目的比较研究小鼠体内外胸腺细胞CD4^＋CD25^＋双阳性T细胞发育的动态变化，为天然调节性T细胞的研究提供基础数据。方法采用14．5天龄胚鼠胸腺进行体外培养，以FACS检测不同时间点胸腺细胞的表型变化，同时计数每个胸腺小叶的细胞数变化。结果胸腺在体内发育的第14．5、15、16、17、18、19天CD4^＋CD25^＋双阳性T细胞的比例、细胞的数量与在体外胸腺培养的第1～6天在胸腺细胞中的比例、细胞数发育趋势相似；CD4^＋CD25^＋双阳性T细胞占CD4^＋T细胞的比例分别为8．19％、16．41％、24．06％、13．62％、8．10％、2．35％，占CD25^＋细胞的比例分别为0．34％、1．08％、2．40％、10．59％、32．51％、34．04％。与体内结果相似，胸腺细胞体外培养的结果显示：在培养的第1～6天，CD4^＋CD25^＋T细胞占CD4^＋T细胞的比例分别为58．29％、12．14％、6．08％、17．78％、9．06％、4．04％，占CD25^＋T细胞的比例分别为3．75％、10．81％、17．20％、51．93％、61．64％、80．06％。结论体外培养的CD4^＋CD25^＋双阳性胸腺细胞数量和比例变化与体内发育变化趋势一致，在体外培养第4天（约等于18．5天胚鼠）和体内发育的第17天该群细胞比例最大．这将为天然调节性T细胞的发生、发育学研究提供有效的参考。

Comparison of the dynamics of CD4+CD25+ mice thymocytes development in vivo and in vitro

Purpose To compare the dynamic changes of CD4~+CD25~+ thymocytes development in vivo and in vitro. Methods Fetal mice thymus lobes were removed at the age of 14.5 days and cultured in complete RPMI-1640 with 20% FBS in vitro.Phenotypes of the thymocytes were analyzed by FACS and the number of cells per lobe was counted. Results It revealed that from day 14.5 to day 19,the number and the percentage of the CD4~+CD25~+ thymocytes varied similarly as their development as in vitro culture in 6 days.The CD4~+CD25~+/CD4~+ percentage was 8.19%,16.41%,24.06%,13.62%,8.10%,2.35% for each and the CD4~+CD25~+/CD25~+ was 0.34%,1.08%,2.40%,10.59%,32.51%,34.04% respectively.In vitro data showed that during the 6 days in vitro culture,the CD4~+CD25~+/CD4~+ percentage was 58.29%,12.14%,6.08%,17.78%,9.06%,4.04% and the CD4~+CD25~+/CD25~+ percentage was 3.75%,10.81%,17.20%,51.93%,61.64%, 80.06% for each. Conclusions These results suggested that the in vitro and in vivo CD4~+CD25~+ thymocytes development was similar,with its peak development on the 4~th day in vitro and the 17~th days in vivo.The above data might help to understand the development of naturally arising CD4~+CD25~+ regulatory T cells.