Gray L S, Huber K S, Gray M C, Hewlett E L, Engelhard V H
Department of Pathology, University of Virginia Health Sciences Center, Charlottesville 22908.
J Immunol. 1989 Mar 1;142(5):1631-8.
Pertussis toxin (PT) has been shown to have a variety of effects on T lymphocyte function, and its activity has been used to suggest the involvement of a G protein in the early events of T lymphocyte activation. In this report, the effects of PT on T lymphocytes have been investigated in detail. PT at a concentration of 10 micrograms/ml rapidly stimulated early events that are normally induced by occupancy of the TCR complex in Jurkat cells and cloned, murine CTL including increased intracellular Ca2+ concentration, serine esterase release, and induction of Ag non-specific target cell lysis. However, 1-h treatment with this concentration of PT induced a state that was refractory to further receptor stimulation in Jurkat cells but not cloned CTL although substrate membrane proteins were modified to a similar extent in both cell lines. The functional effects of PT were mimicked by the B oligomer of PT which did not, however, catalyze ADP-ribosylation of membrane proteins. In addition, overnight exposure of Jurkat cells to a lower concentration of PT also modified substrate membrane proteins but did not inhibit receptor stimulation. These findings indicate that PT catalyzed ADP-ribosylation of a G protein does not account for the actions of the toxin on T lymphocytes. Finally, direct stimulation of increased intracellular Ca2+ concentration by PT and the B oligomer only occurred in T lymphocytes expressing CD3. This suggests that the mitogenic effect of PT holotoxin is mediated by the interaction of the B oligomer with CD3 and that this may account for many of the effects of PT holotoxin both in vivo and in vitro.
百日咳毒素（PT）已被证明对T淋巴细胞功能有多种影响，其活性被用于提示G蛋白参与T淋巴细胞激活的早期事件。在本报告中，已详细研究了PT对T淋巴细胞的影响。浓度为10微克/毫升的PT迅速刺激了通常由Jurkat细胞和克隆的小鼠CTL中TCR复合物占据所诱导的早期事件，包括细胞内Ca2+浓度增加、丝氨酸酯酶释放以及诱导Ag非特异性靶细胞裂解。然而，用该浓度的PT处理1小时会诱导一种状态，在Jurkat细胞中对进一步的受体刺激产生抗性，但在克隆的CTL中则不会，尽管两种细胞系中的底物膜蛋白被修饰的程度相似。PT的功能效应被PT的B寡聚体模拟，然而，B寡聚体并不催化膜蛋白的ADP核糖基化。此外，将Jurkat细胞过夜暴露于较低浓度的PT也会修饰底物膜蛋白，但不会抑制受体刺激。这些发现表明，PT催化的G蛋白ADP核糖基化并不能解释该毒素对T淋巴细胞的作用。最后，PT和B寡聚体对细胞内Ca2+浓度增加的直接刺激仅发生在表达CD3的T淋巴细胞中。这表明PT全毒素的促有丝分裂作用是由B寡聚体与CD3的相互作用介导的，这可能解释了PT全毒素在体内和体外的许多作用。
