AMD3100干预调节性T细胞迁移机制研究

AMD3100 imposes blockade on CXCR4^+ regulatory T cell migration

CXCR4+细胞在CD4+CD25+Foxp3+调节性T细胞亚群中占有一定的比例。趋化因子CXCL12与细胞表面的特异性受体CXCR4相互作用,调节这些细胞的迁移和归巢等生理过程。AMD3100是一种人工合成的大环类拮抗剂,可特异性拮抗CXCR4。本研究采用磁珠亲和细胞分选术纯化BALB/c小鼠脾脏CD4+CD25+调节性T细胞,并采用transwell共培养系统,研究AMD3100对调节性T细胞迁移的影响。研究发现,AMD3100以剂量依赖性模式抑制CXCR4+CD4+CD25+T细胞从transwell培养系统的上室迁移至下室,采用中和抗体阻断CXCR4可观察到相似效应。当AMD3100终浓度为2.0μg/ml时,迁移到下室的CXCR4+细胞占总数的2.2%,显著低于磷酸盐缓冲液对照组(36.2%)(P<0.01)。此外,CD4+CD25+细胞24h迁移率也显著下降(AMD3100处理组和磷酸盐缓冲液对照组分别为3.1%和35.5%,P<0.01)。提示AMD3100可特异性抑制CXCR4+CD4+CD25+细胞迁移。由于CXCR4是CXCL12的特异性受体,这一效应提示AMD3100可削弱CXCL12的作用。此外,由于AMD3100处理后可使CD4+CD25+细胞24h迁移率下降,提示这种拮抗剂有可能短时间内削弱调节性T细胞的功能。

It is known that a fraction of Foxp3^＋ CD4^＋ CD25^＋ regulatory T cells express CXCR4 molecule. CXCL12 may interact with CXCR4 on these cells and modulate their migration and homing. The mechanism remains to be clarified. AMD3100 is known as a pharmacologic inhibitor of CXCR4. In the current study, splenic CD4^＋ CD25^＋ regulatory T cells were isolated from BALB/c mice by magnetic affinity cell sorting and cultured in a transwell system. The effect of AMD3100 on regulatory T cell migration was evaluated and compared with neutralizing antibody against CXCR4. It showed that AMD3100 inhibited CXCR4^＋ regulatory T cell migration from the upper chamber to the lower chamber in a dose-dependent manner, similar to the effect of neutralizing antibody against CXCR4. Upon AMD3100 treatment at a concentration of 2.0 μg/ml, the percentage of CXCR4^＋ subset was significantly decreased to a level of 2.2 % in the ceils harvested from the lower chamber, which was significantly lower than that in the control phosphate-buffered solution （PBS） group （36.2%） （P（0.01）. In addition, the percentage of migrated CD4^＋ CD25^＋ cell after cultured for 24h was significantly decreased （3.1% in AMD3100-treated group versus 35.5 % in control PBS group; P（0.01）. These results implied that AMD3100 specifically inhibit CXCR4^＋ CD4^＋ CD25^＋ cell migration. Since CXCR4 is a specific receptor for CXCL12, it is likely that AMD3100 may inhibited CXCL12 function. Moreover, since the proportion of migrated CD4^＋ CD25^＋ cells at 24 h was markedly decreased in response to AMD3100 treatment, it suggests that AMD3100 may shortly inhibit regulatory T cell function under certain conditions.