Biopolymers and cell. 2000; 16 (3): 225 - 228

Effects of interferon-a//? on Ca influx and binding in murine thymocytes

E. V. Dolgaya, O. M. Rozhmanova, L. N. Stelmakh, A. V. Mlransky, Yu. J. Kudryavets

In order to determine the role of calcium in interferon (IFN)-induced immunomodulation, we investigated calcium transport and binding induced by murine JFN-a/p in murine thymocytes. By radiometric method, it was found that a rapid, more than 5-fold, increase in Ca influx developed and reached a plateau within 10 min. At the same time the amount of Ca associated with the cell surface half decreased. During next 30 min the recovery of Ca 2+ binding to control level in INF-induced lymphocytes occured. Ca + influx in thymocytes was dose-dependent. The maximal increase in calcium influx was observed at the IFN concentration of 600 W/ml. Pretreatment of thymocytes with a calcium channel blacker, verapamil, at the doses about 30mkM for 20 min before IFN application significantly decreased Ca influx. Depolarization of thymocytes up to 25 mM by increasing the extracellular K+ concentration resulted in complete inhibition of Ca + influx. Our data indicate that in murine thymocytes IFN-induced calcium influx occcured via voltage-operated calcium channels.