Abstract
Isolated and combined effects of the calcium ionophore A23187 and of the protein kinase C activator phorbol myristate acetate (PMA) on T cell activation parameters were analysed on unprimed Balb/c lymph node T lymphocytes (LNL). High doses of PMA were mitogenic for resting T cells, but non-mitogenic doses of PMA induced T cell proliferation in combination with A23187, which was non-mitogenic by itself. Mitogenesis induced by a combination of A23187 and PMA (A23187/PMA) showed the following characteristics: it was not abolished after extensive depletion of accessory cells; purified L3T4+, but not Lyt2+ T cells responded in the absence of accessory cells; mitogenesis was completely blocked by a mixture of two monoclonal antibodies directed to the murine interleukin 2 (IL-2) receptor (7D4/3C7mAbs); cyclosporin A, dibutyril cyclic AMP, and T cell K+ channel blockers quinine and verapamil all blocked mitogenesis. A marked synergism between A23187 and PMA was noted in induction of T cell enlargement, IL-2 release, and induction of IL-2 responsiveness. No synergism was noted in IL-2 receptor expression, A23187 and PMA being able to induce IL-2 receptors alone. Calcium ionophore induced IL-2 receptor expression, but failed to induce IL-2 release and IL-2 responsiveness. Addition of A23187/PMA to the IL-2-dependent CTL-L clone did not result in cell proliferation. Addition of A23187/PMA to Con A-activated T cell blasts leads to a vigorous proliferative response. This response is blocked by 7D4/3C7 mAbs, indicating a role for endogenously produced IL-2 in this case. The results indicate that T cell mitogenesis by A23187/PMA is IL-2-dependent, and suggest a critical role for protein kinase C in IL-2 release and induction of IL-2 responsiveness. In addition, the data suggest distinct, but co-operative pathways of IL-2 receptor induction, controlled by elevated Ca2+ alone and by protein kinase C. Subsequent intracellular events of T cell activation by A23187/PMA may be quite similar to those triggered by Con A, since both kinds of stimulation are blocked by agents such as cyclosporin A, dbcAMP and K+ channel blockers.
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Selected References
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- Albert F., Hua C., Truneh A., Pierres M., Schmitt-Verhulst A. M. Distinction between antigen receptor and IL 2 receptor triggering events in the activation of alloreactive T cell clones with calcium ionophore and phorbol ester. J Immunol. 1985 Jun;134(6):3649–3655. [PubMed] [Google Scholar]
- Berridge M. J. Inositol trisphosphate and diacylglycerol as second messengers. Biochem J. 1984 Jun 1;220(2):345–360. doi: 10.1042/bj2200345. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Britton S., Palacios R. Cyclosporin A--usefulness, risks and mechanism of action. Immunol Rev. 1982;65:5–22. doi: 10.1111/j.1600-065x.1982.tb00425.x. [DOI] [PubMed] [Google Scholar]
- Castagna M., Takai Y., Kaibuchi K., Sano K., Kikkawa U., Nishizuka Y. Direct activation of calcium-activated, phospholipid-dependent protein kinase by tumor-promoting phorbol esters. J Biol Chem. 1982 Jul 10;257(13):7847–7851. [PubMed] [Google Scholar]
- Chandy K. G., DeCoursey T. E., Cahalan M. D., McLaughlin C., Gupta S. Voltage-gated potassium channels are required for human T lymphocyte activation. J Exp Med. 1984 Aug 1;160(2):369–385. doi: 10.1084/jem.160.2.369. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coggeshall K. M., Cambier J. C. B cell activation. VIII. Membrane immunoglobulins transduce signals via activation of phosphatidylinositol hydrolysis. J Immunol. 1984 Dec;133(6):3382–3386. [PubMed] [Google Scholar]
- Depper J. M., Leonard W. J., Krönke M., Noguchi P. D., Cunningham R. E., Waldmann T. A., Greene W. C. Regulation of interleukin 2 receptor expression: effects of phorbol diester, phospholipase C, and reexposure to lectin or antigen. J Immunol. 1984 Dec;133(6):3054–3061. [PubMed] [Google Scholar]
- Imboden J. B., Stobo J. D. Transmembrane signalling by the T cell antigen receptor. Perturbation of the T3-antigen receptor complex generates inositol phosphates and releases calcium ions from intracellular stores. J Exp Med. 1985 Mar 1;161(3):446–456. doi: 10.1084/jem.161.3.446. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Julius M. H., Simpson E., Herzenberg L. A. A rapid method for the isolation of functional thymus-derived murine lymphocytes. Eur J Immunol. 1973 Oct;3(10):645–649. doi: 10.1002/eji.1830031011. [DOI] [PubMed] [Google Scholar]
- Lillehoj H. S., Malek T. R., Shevach E. M. Differential effect of cyclosporin A on the expression of T and B lymphocyte activation antigens. J Immunol. 1984 Jul;133(1):244–250. [PubMed] [Google Scholar]
- Maino V. C., Green N. M., Crumpton M. J. The role of calcium ions in initiating transformation of lymphocytes. Nature. 1974 Sep 27;251(5473):324–327. doi: 10.1038/251324b0. [DOI] [PubMed] [Google Scholar]
- Malek T. R., Robb R. J., Shevach E. M. Identification and initial characterization of a rat monoclonal antibody reactive with the murine interleukin 2 receptor-ligand complex. Proc Natl Acad Sci U S A. 1983 Sep;80(18):5694–5698. doi: 10.1073/pnas.80.18.5694. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Nishizuka Y. The role of protein kinase C in cell surface signal transduction and tumour promotion. Nature. 1984 Apr 19;308(5961):693–698. doi: 10.1038/308693a0. [DOI] [PubMed] [Google Scholar]
- O'Flynn K., Zanders E. D., Lamb J. R., Beverley P. C., Wallace D. L., Tatham P. E., Tax W. J., Linch D. C. Investigation of early T cell activation: analysis of the effect of specific antigen, interleukin 2 and monoclonal antibodies on intracellular free calcium concentration. Eur J Immunol. 1985 Jan;15(1):7–11. doi: 10.1002/eji.1830150103. [DOI] [PubMed] [Google Scholar]
- Ortega G., Robb R. J., Shevach E. M., Malek T. R. The murine IL 2 receptor. I. Monoclonal antibodies that define distinct functional epitopes on activated T cells and react with activated B cells. J Immunol. 1984 Oct;133(4):1970–1975. [PubMed] [Google Scholar]
- Truneh A., Albert F., Golstein P., Schmitt-Verhulst A. M. Early steps of lymphocyte activation bypassed by synergy between calcium ionophores and phorbol ester. Nature. 1985 Jan 24;313(6000):318–320. doi: 10.1038/313318a0. [DOI] [PubMed] [Google Scholar]
- Weiss A., Imboden J., Shoback D., Stobo J. Role of T3 surface molecules in human T-cell activation: T3-dependent activation results in an increase in cytoplasmic free calcium. Proc Natl Acad Sci U S A. 1984 Jul;81(13):4169–4173. doi: 10.1073/pnas.81.13.4169. [DOI] [PMC free article] [PubMed] [Google Scholar]