Nishimura T, Takeuchi Y, Gao X H, Urano K, Habu S
Department of Immunology, Tokai University School of Medicine, Iseraha, Japan.
J Immunol. 1991 Oct 1;147(7):2094-9.
To assess the molecular mechanisms involved in cell-cell interactions of T cells, we produced a mAb that could block PMA-induced homotypic T cell aggregation. The established mAb (TN14 mAb) showed an inhibitory effect on T cell aggregation as large as that of mAb against lymphocyte function-associated Ag-1. TN14 mAb showed a strong reactivity with cell surface molecules on T cells, whereas it did not react with any cell surface Ag on macrophages, B cells, bone marrow cells, or WEHI 164 cells, which were used for immunization. However, all cell lysates could react with TN14 mAb in Western blotting analysis, indicating that TN14 mAb recognized some cytoplasmic protein. From biochemical analysis, TN14 mAb was demonstrated to react with the 43-kDa cytoskeletal protein actin. Moreover, from an immunoprecipitation study, TN14 mAb was demonstrated to cross-react with the Thy-1 molecule on T cells. The binding activity of TN14 mAb with the Thy-1 molecule on T cells was strongly blocked by the addition of purified actin, indicating that TN14 mAb recognized an actin-related epitope of the Thy-1 molecule. TN14 mAb blocked not only T cell aggregation but also cell-mediated cytotoxicity by CTL. These results strongly support the hypothesis that the Thy-1 molecule, a member of the Ig superfamily, may play an important role in cell-cell interactions of T cells.
为了评估参与T细胞细胞间相互作用的分子机制，我们制备了一种能够阻断佛波酯（PMA）诱导的同型T细胞聚集的单克隆抗体。所制备的单克隆抗体（TN14单克隆抗体）对T细胞聚集的抑制作用与针对淋巴细胞功能相关抗原-1的单克隆抗体一样强。TN14单克隆抗体与T细胞表面分子有强烈反应，而与用于免疫的巨噬细胞、B细胞、骨髓细胞或WEHI 164细胞的任何细胞表面抗原均无反应。然而，在蛋白质印迹分析中，所有细胞裂解物都能与TN14单克隆抗体反应，这表明TN14单克隆抗体识别某种细胞质蛋白。通过生化分析，证明TN14单克隆抗体与43 kDa的细胞骨架蛋白肌动蛋白反应。此外，通过免疫沉淀研究，证明TN14单克隆抗体与T细胞上的Thy-1分子发生交叉反应。加入纯化的肌动蛋白可强烈阻断TN14单克隆抗体与T细胞上Thy-1分子的结合活性，这表明TN14单克隆抗体识别Thy-1分子的一个肌动蛋白相关表位。TN14单克隆抗体不仅阻断T细胞聚集，还阻断细胞毒性T淋巴细胞（CTL）介导的细胞毒性。这些结果有力地支持了以下假说：免疫球蛋白超家族成员Thy-1分子可能在T细胞的细胞间相互作用中起重要作用。
