Mukai T, Iwasaki M, Gao P, Tomura M, Yashiro-Ohtani Y, Ono S, Murai M, Matsushima K, Kurimoto M, Kogo M, Matsuya T, Fujiwara H, Hamaoka T
Department of Oncology, Biomedical Research Center, Osaka University Graduate School of Medicine, 2-2 Yamada-oka, Japan.
J Leukoc Biol. 2001 Sep;70(3):422-30.
The chemokine receptor CCR5 has been implicated in the recruitment of T cells to inflammatory sites. However, the regulation of CCR5 induction on T cells and its contribution to T cell adhesiveness are poorly understood. Using a Th1 clone, 2D6, that can be maintained with interleukin (IL)-12 or IL-2 alone (designated 2D6(IL-12) or 2D6(IL-2), respectively), we investigated how CCR5 is induced on T cells and whether CCR5 is responsible for up-regulating the function of adhesion molecules. 2D6(IL-12) grew, forming cell aggregates, in culture containing IL-12. This was due to lymphocyte function-associated antigen (LFA)-1-intercellular adhesion molecule (ICAM)-1 interaction, because 2D6(IL-12) expressed both LFA-1 and ICAM-1 and cell aggregation was inhibited by anti-ICAM-1 monoclonal antibody. Despite comparable levels of LFA-1 and ICAM-1 expression, 2D6(IL-2) cells did not aggregate in culture with IL-2. It is important that there was a critical difference in CCR5 expression between 2D6(IL-12) and 2D6(IL-2); the former expressed high levels of CCR5, and the latter expressed only marginal levels. Both types of cells expressed detectable albeit low levels of RANTES (regulated on activation, normal T expressed and secreted) mRNA. Unlike IL-12 or IL-2, IL-18 induced high levels of RANTES mRNA expression without modulating CCR5 expression. Therefore, combined stimulation with IL-12 and IL-18 strikingly up-regulated 2D6 cell aggregation. Notably, LFA-1-mediated aggregation of 2D6(IL-12) cells was suppressed by anti-CCR5 antibody. These results indicate that IL-12 plays a critical role in CCR5 expression on Th1 cells and consequently contributes to CCR5-mediated activation of LFA-1 molecules.
趋化因子受体CCR5与T细胞向炎症部位的募集有关。然而，CCR5在T细胞上的诱导调控及其对T细胞黏附性的作用尚不清楚。我们使用一个Th1克隆2D6，它可以分别仅用白细胞介素（IL）-12或IL-2维持培养（分别命名为2D6(IL-12)或2D6(IL-2)），研究了CCR5如何在T细胞上被诱导以及CCR5是否负责上调黏附分子的功能。2D6(IL-12)在含有IL-12的培养物中生长并形成细胞聚集体。这是由于淋巴细胞功能相关抗原（LFA）-1-细胞间黏附分子（ICAM）-1相互作用，因为2D6(IL-12)同时表达LFA-1和ICAM-1，且细胞聚集被抗ICAM-1单克隆抗体抑制。尽管LFA-1和ICAM-1表达水平相当，但2D6(IL-2)细胞在与IL-2共培养时并不聚集。重要的是，2D6(IL-12)和2D6(IL-2)在CCR5表达上存在关键差异；前者表达高水平的CCR5，而后者仅表达微量水平。两种类型的细胞均表达可检测到的、尽管水平较低的调节激活正常T细胞表达和分泌因子（RANTES）mRNA。与IL-12或IL-2不同，IL-18诱导高水平的RANTES mRNA表达而不调节CCR5表达。因此，IL-12和IL-18联合刺激显著上调2D6细胞聚集。值得注意的是,抗CCR5抗体抑制了LFA-1介导的2D6(IL-12)细胞聚集。这些结果表明，IL-12在Th1细胞CCR5表达中起关键作用，从而有助于CCR5介导的LFA-1分子激活。
