PMA和PHA对活化早期人胎儿胸腺细胞表型分化的研究

本文利用妊娠中期水囊引产的人胎儿胸腺细胞，采用双色免疫荧光染色技术用流式细胞计分析了佛波酯（ＰＭＡ，一种ＰＫＣ激酶活化剂）和ＰＨＡ作用于胸腺细胞０．５，３，６，１２和１８小时等不同时间对胸腺细胞ＣＤ４＋ＣＤ８＋亚群（ＤＰ）表型变化的影响。结果表明ＰＭＡ作用３０分钟就可以明显下调ＤＰ亚群ＣＤ４分子表达，而其对ＣＤ８分子的下调作用明显晚于对ＣＤ４分子的作用。ＰＨＡ则不表现对ＣＤ４分子的下调作用。我们发现ＰＭＡ和ＰＨＡ还可下调ＣＤ３的表达，但是ＰＭＡ和ＰＨＡ对ＩＬ－２受体和ＨＬＡ－Ⅰ类抗原的表达有促进作用。而对ＤＲ分子均无明显作用。这些结果证实胸腺ＤＰ细胞在外界活化因子作用下一些重要的细胞表面分子发生了改变，表明胸腺ＤＰ细胞具有继续分化的潜能。提示在ＰＭＡ和ＰＨＡ诱导的胸腺细胞活化和增植过程中细胞表面分子的表达可能受不同细胞活化机制的调控。因此，探讨ＰＭＡ和ＰＨＡ诱导细胞表型变化的机理及其与胸腺细胞活化的关系可能有助于对Ｔ细胞活化机理研究。

STUDY OF PHENOTYPIC DIFFERENTIATION INDUCED BY PMA AND PHA ON HUMAN FETAL THYMOCYTE DURING EARLY ACTIVATION

The effects of phenotypic differentiation induced by PMA an PHA on human fetal thymocytes have been ana-lyzed with double fluorescent- staining and flowcytometry. The results indicated that PMA cultured with (DP)thy-mocytes for very short time(0.5 hour)could obviously induce down-modulation of CD4 expression on human fetalthymocytes.However,the down-modulated expression of CD8 on thymocytes induced by PMA was delayed butPHA did not induce down-modulation of the expression of CD4 on thymocytes.These results suggest that PMAmay have a selective action on CD 4 and CD8 of human fetal thymocytes. We found that both PMA and PHA couldincrease the expression of IL-2 receptor and induce down-modulation of CD3 expression on the thymocytes. Therewere obviously different actions between PMA and PHA on the expression of CD3,CD4,CD8 and CD25 on thy-mocytes. These results suggest that expression of surface molecules on(DP)thymocytes may be controlled by dif-ferent mechanisms during early activation and may play certain important role on T cell differentiation and activa-tion, On the other hand,we found that CPZ (Chlorpromazine)which is a Ca inhibitor could obviously inhibitthe action of PMA on the expression of CD4 and CD8 on thymocyte. It shows that Ca might have some impor-tant modulation action on activation and proliferation of T cells induced by PMA.our results indicated that during early activation by PMA the expression of CD3 and CD4 on human fetal thy-mocytes were at low level,the significance of this appearance on T cell differentiation and activation should be fur-ther studied.It may be very useful for understanding the mechanisms of T cell activation.