[Investigation of interferon-induced system of 2',5'-oligoadenylate in rat lymphoid cells exposed to ionizing radiation]. / Vyvchennia interferonindukovanoï systemy 2',5'-olihoadenilatu v limfoïdnykh klitynakh shchuriv sa diï ionizatsiinoho vyprominiuvannia.

The key components of interferon-dependent 2',5'-oligoadenylate system were studied in the rat spleen and thymus lymphoid cells under the action of ionizing radiation and interferon inducers treatment. It was established that the irradiation of animals by 0.5 Gy dose causes the increase of intracellular level of the 2',5'-oligoadenylates (A2'p5'A, (A2'p)2A) and the enhancement of the 2',5'-oligoadenylate-synthetase activity. The pre-incubation of isolated splenocytes and thymocytes with interferon inducers (cycloferone, mitogenic lectines and poly(I) x poly(C) caused the amplification of post-radiactive 2',5'-oligoadenylate accumulation and 2',5'-oligoadenylate-synthetase activity stimulation. The obtained results allow us to suggest the activation of 2',5'-oligoadenylate messenger system in rat immunocompetent cells under the action of ionizing radiation. It might be a result of the activation of protective mechanisms, connected with interferon induction. The effect of interferon inducers on the investigated cascade components may be considered as the manifestation of their radioprotective properties.

[Activity of dsRNA-dependent protein kinase in rat lymphoid cells under the effect of X-ray irradiation]. / Aktyvnist' dsRNK-zalezhnoï proteïnkinazy v limfoïdnykh klitynakh shchuriv za diï na nykh renthenivs'koho vyprominiuvannia.

The activity of dsRNA-dependent protein kinase, which is the key enzyme of the interferon signal system, was studied in the rat spleen and thymus lymphocytes under the influence of X-ray irradiation at 0.5 and 1 Gy doses and interferon inducers administration. An increase of the enzyme activity was established in the presence of FGA, concanavaline A, poly(I).poly(C) in vitro. The effect is intensified under the irradiation by 0.5 Gy dose. The protein kinase activity in lymphocytes is amplified in proportion to poly(I).poly(C) concentration, that was most pronounced in the irradiated animals. The comparative analysis of the action of interferon inducers on the dsRNA-dependent protein kinase activity was carried out. Two biological systems were used: in vivo (when the preparations were injected to the experimental animals) and in vivo (under the preincubation of isolated lymphocytes with the inducers). It was shown that the combined action of radiation and interferon inducers causes the stimulation of dsRNA-dependent protein kinase activity.