Loss of FOXP3 expression in natural human CD4+CD25+ regulatory T cells upon repetitive in vitro stimulation
Loss of FOXP3 expression in natural human CD4+CD25+ regulatory T cells upon repetitive in vitro stimulation
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DOI：
10.1002/eji.200838904
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发表时间：
2009-04-01
影响因子：
5.4
通讯作者：
Edinger, Matthias
中科院分区：
文献类型：
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作者：
Hoffmann, Petra;Boeld, Tina J.;Edinger, Matthias
CD4(+)CD25（+）自然调节性T细胞（Treg）的过继转移是治疗自身免疫性疾病和预防移植后同种异体反应的一种有前途的策略。临床试验探索这一策略需要有效的体外扩增这种罕见的细胞群。迄今为止开发的方案依赖于在培养开始之前对Treg进行高级纯化，这一过程仍然受到缺乏Treg细胞特异性表面标记物的阻碍。CD127（+）细胞的损耗被证明可以将活化的常规T细胞从天然Treg细胞群中分离出来，从而分离出具有天然Treg所有功能和分子特征的高富集FOXP3（+）细胞。在这里，我们证明了在体外扩增后，FOXP3基因位点保守区域的CpG甲基化在CD4(+)CD25(+)CD127（低）Treg中增加，与FOXP3表达的缺失和促炎细胞因子的出现相关。进一步分析发现，CD45RA(-)FOXP3（+）记忆型Treg是转化细胞的主要来源，而来自同一供体的CD45RA(+)FOXP3(+) Treg在体外扩增3周内没有转化。因此，Treg细胞系分化似乎并不代表最终的命运决定，因为天然Treg在反复的TCR刺激后会失去其细胞类型特异性特征。
The adoptive transfer of CD4(+)CD25(+) natural regulatory T cells (Treg) is a promising strategy for the treatment of autoimmune diseases and the prevention of alloresponses after transplantation. Clinical trials exploring this strategy require efficient in vitro expansion of this rare cell population. Protocols developed thus far rely on high-grade purification of Treg prior to culture initiation, a process still hampered by the lack of Treg cell-specific surface markers. Depletion of CD127(+) cells was shown to separate activated conventional T cells from natural Treg cell populations allowing the isolation of highly enriched FOXP3(+) cells with all functional and molecular characteristics of natural Treg. Here, we demonstrate that upon in vitro expansion, CpG methylation in a conserved region within the FOXP3 gene locus increased in CD4(+)CD25(+)CD127(low) Treg, correlating with loss of FOXP3 expression and emergence of pro-inflammatory cytokines. Further analysis identified CD45RA(-)FOXP3(+) memory-type Treg as the main source of converting cells, whereas CD45RA(+)FOXP3(+) Treg from the same donors showed no conversion within 3 wk of in vitro expansion. Thus, Treg cell lineage differentiation does not seem to represent a final fate decision, as natural Treg can lose their cell-type-specific characteristics after repetitive TCR stimulation.