Osorio L M, Ordonez C, Garcia C A, Jondal M, Chow S C
Departamento de Biologia, Instituto Nacional de Oncologia y Radiobiologica (INOR), La Habana, Cuba.
Cell Immunol. 1995 Nov;166(1):44-52. doi: 10.1006/cimm.1995.0006.
Several studies have demonstrated that addition of soluble anti-CD6 mAbs to 12-O-tetradecanoylphorbol 13-acetate (TPA)-treated naive T cells can induce cell proliferation. We showed in the present study that cell proliferation in TPA-treated T cell cultures can be enhanced several fold when the anti-CD6 mAbs are either immobilized or crosslinked with rabbit anti-mouse immunoglobulins (RAM Ig). Using a src family protein tyrosine kinase (PTK) inhibitor, herbimycin A, the cell proliferation induced by the anti-CD6 mAb, IOR-T1, in TPA-treated T cells were effectively abolished. Analysis of the cellular proteins in these cells after crosslinking the CD6 receptor with IOR-T1 (followed by RAM Ig) in the presence of TPA resulted in an increased level of tyrosine phosphorylation. Pretreatment of native T cells with herbimycin A (0.5 and 1 microgram/ml) for 18 hr completely inhibited the tyrosine phosphorylation on cellular substrates in T cell cultures stimulated with IOR-T1/RAM Ig and TPA. Similar concentrations of herbimycin A also inhibited the increase in IL-2 mRNA expression and cell proliferation in T cell cultures after IOR-T1/RAM Ig and TPA treatment. Furthermore, the increase in cytosolic free Ca2+ concentration in naive T cells after crosslinking of the CD6 receptor with IOR-T1/RAM Ig was also inhibited by herbimycin A. Taken together, our results suggest that CD6-mediated T cell proliferation is IL-2 dependent, and involves tyrosine kinase activity which is strictly dependent on protein kinase C activation.
多项研究表明，将可溶性抗CD6单克隆抗体添加到经12 - O - 十四烷酰佛波醇13 - 乙酸酯（TPA）处理的未活化T细胞中可诱导细胞增殖。我们在本研究中表明，当抗CD6单克隆抗体固定化或与兔抗小鼠免疫球蛋白（RAM Ig）交联时，TPA处理的T细胞培养物中的细胞增殖可增强数倍。使用src家族蛋白酪氨酸激酶（PTK）抑制剂除草菌素A，可有效消除抗CD6单克隆抗体IOR - T1在TPA处理的T细胞中诱导的细胞增殖。在TPA存在下，用IOR - T1（随后用RAM Ig）交联CD6受体后，分析这些细胞中的细胞蛋白，结果显示酪氨酸磷酸化水平升高。用除草菌素A（0.5和1微克/毫升）预处理天然T细胞18小时，可完全抑制IOR - T1/RAM Ig和TPA刺激的T细胞培养物中细胞底物上的酪氨酸磷酸化。相似浓度的除草菌素A也抑制了IOR - T1/RAM Ig和TPA处理后T细胞培养物中IL - 2 mRNA表达的增加和细胞增殖。此外，除草菌素A也抑制了用IOR - T1/RAM Ig交联CD6受体后未活化T细胞中胞质游离Ca2+浓度的增加。综上所述，我们的结果表明，CD6介导的T细胞增殖依赖于IL - 2，且涉及酪氨酸激酶活性，而酪氨酸激酶活性严格依赖于蛋白激酶C的激活。
