Wang JM, Xu L, Murphy WJ, Taub DD, Chertov O
Biological Carcinogenesis and Development Program, SAIC Frederick, Frederick, Maryland, 21702
Methods. 1996 Aug;10(1):135-44. doi: 10.1006/meth.1996.0087.
Although IL-8 has been reported to be a chemoattractant for T cells in vivo and in vitro, this has been a controversial issue. By using freshly purified human T cells (>90% CD3(+)), we demonstrated consistent T-cell migration in response to recombinant human IL-8 in vitro. However, highly purified T cells, when incubated at 37°C for more than 12 h or cultured overnight in the presence of anti-CD3 antibody, showed a markedly reduced capacity to migrate in response to IL-8. This reduction in chemotaxis was associated with a decrease in binding of 125I-IL-8 to T cells. Northern blots showed that freshly purified T cells expressed both IL-8 receptor type A and type B transcripts. Steady-state levels of mRNA for IL-8RA and IL-8RB in T cells were progressively reduced with time by incubation of the cells at 37°C with or without anti-CD3. The inability of cultured T cells to migrate in response to IL-8 accounts for the contradictory published reports on this issue. In vivo administration of IL-8 in rats resulted in the infiltration at the injection site of neutrophils followed by T cells, and this later T-cell infiltration was reported to be partially blocked by selective depletion of neutrophils. These observations raised the possibility that IL-8 may trigger neutrophils to release a factor(s) that may also participate in the T-cell recruitment. Neutrophil granule proteins, defensins, and CAP37/azurocidin released upon stimulation of cells by IL-8 were shown to induce human T-cell migration in vitro. Subcutaneous injection of defensins into SCID mice engrafted with human PBL resulted in significant infiltration by human CD3(+) T lymphocytes. These results indicate that IL-8 is able not only to act directly and induce migration of T lymphocytes that express IL-8 receptors, but also to act indirectly by activating neutrophils to release additional T-cell chemoattractants.
尽管有报道称白细胞介素-8（IL-8）在体内和体外都是T细胞的趋化因子，但这一直是一个有争议的问题。通过使用新鲜纯化的人T细胞（>90% CD3(+)），我们证实在体外重组人IL-8能一致地诱导T细胞迁移。然而，高度纯化的T细胞在37℃孵育超过12小时或在抗CD3抗体存在下过夜培养后，对IL-8的迁移反应能力显著降低。这种趋化性的降低与125I-IL-8与T细胞结合的减少有关。Northern印迹显示，新鲜纯化的T细胞表达A、B两型IL-8受体转录本。在有或无抗CD3的情况下，将细胞在37℃孵育，T细胞中IL-8RA和IL-8RB的mRNA稳态水平随时间逐渐降低。培养的T细胞对IL-8无迁移反应，这解释了关于该问题已发表报道的矛盾之处。在大鼠体内注射IL-8导致中性粒细胞先于T细胞在注射部位浸润，据报道，随后的T细胞浸润会因中性粒细胞的选择性耗竭而部分受阻。这些观察结果提示，IL-8可能触发中性粒细胞释放一种（些）也可能参与T细胞募集的因子。研究表明，IL-8刺激细胞后释放的中性粒细胞颗粒蛋白、防御素和CAP37/天青杀素能在体外诱导人T细胞迁移。将防御素皮下注射到植入人外周血淋巴细胞（PBL）的严重联合免疫缺陷（SCID）小鼠中，导致人CD3(+) T淋巴细胞显著浸润。这些结果表明，IL-8不仅能够直接作用并诱导表达IL-8受体的T淋巴细胞迁移，还能够通过激活中性粒细胞释放其他T细胞趋化因子而间接发挥作用。
