engleski

R1.1 cell line, constitutively expressing k-opioid receptors, as a model for studying the interaction of k-opioids with T-cell activation.

Increase of free intracellular Ca++ is an important early event in T-cell activation. Ca++ has been shown as a second messenger in transducing a signal induced by opioid agonists in neuronal cells. Cells of hematopoietic origin also express opioid receptors, but data on the role of Ca++ in signal transduction of opioids in these cells are scarce. The aim of this study was to examine whether ligation of kappa-opioid receptors on T-lymphocytes involves Ca++ signalling pathway, and if so, do kappa-opioid agonists interfere with T-lymphocyte activation at the level of Ca++. To that purpose, we used the R1.1 T-cell line, originating from mouse thymoma, which constitutively and selectively expresses kappa-opioid receptors. We examined: (a) whether R1.1 cells would respond to activation by anti-CD3 and Con-A by increased Ca++, (b) whether acute treatment of R1.1 cells with selective kappa-opioid agonist Dynorphin1-17 would alter basal Ca++, and (c) whether Dynorphin1-17 would interfere with anti-CD3-elevated Ca++. The changes in Ca++ were traced on FACScan after labelling the R1.1 cells with Fluo-3AM. The data obtained have shown dose-dependent elevation of Ca++ following the activation by anti-CD3 or Con-A. However, the increase was of significantly lower intensity than that obtained with thymus cells, activated in a similar way. Acute treatment of R1.1 cells with Dynorphin1-17 resulted in decrease of basal, and attenuation of anti-CD3-elevated Ca++ in them. In conclusion, R1.1 cells, selectively expressing kappa-opioid receptors, could be activated by anti-CD3 to increase Ca++. That feature of R1.1 cells, together with their selective expression of kappa-opioid receptors, makes them a suitable model for studying the mechanism of interaction of kappa-opioids with T-cell activation at the level of signalling via Ca++.

T lymphocytes - kappa opioid receptors -signal transduction - Ca++

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