γ线照后PHA、ConA和PWM激活的人血淋巴细胞转化、DNA单链断裂及其修复比较

COMPARISON OF TRANSFORMATION,DNA SINGLE STRAND BREAKS AND ITS REPAIR IN HUMAN BLOOD LYMPHOCYTES STIMULATED WITH PHA,ConA AND PWM FOLLOWING EXPOSURE TO γ-RAYS

本文采用~3H-TdR参入法和羟基磷灰石层析法,比较了^(60)Coγ射线照射后PHA、ConA、PWM激活的人血淋巴细胞的转化、DNA单链断裂及其修复,结果表明:受照后淋巴细胞转化受抑,在0—8Gy剂量范围内,剂量效应呈双相线性关系,其中PWM激活的细胞对射线的敏感性最低。三种细胞受照后DNA发生单链断裂,在0—30Gy范围内,与剂量呈线性相关,三者之间无显著差异。受15Gy照射后,细胞在37℃条件下能重接DNA断链,但重接不完全,重接后如经较长时间保温仍会发生再断裂,PWM激活的细胞重接修复率最高。淋巴细胞转化对辐射的敏感性可能与DNA断链的重接修复能力有关。

The transformation, DNA single strand breaks and its repair inhuman peripheral blood lymphocytes stimulated with PHA, ConA and PWM respecti-vely following exposure to ^(60)Co γ-rays were analyzed by ~3H-thymidine incorporationand hydroxylapatite chromatography. The transformation of lymphocytes stimulatedwith PHA, ConA and PWM were suppressed by γ-rays and the dose-effect curveswere biphasic within the range of 0-8 Gy. The lymphocytes stimulated with PWMwere the most resistant to γ-rays. The extent of DNA single strand breaks in lymp-hocytes induced by γ-rays was linearly related to the dose within the range of 0-30Gy and there was no marked difference in the three kinds of lymphocytes. After aperiod of post-irradiation (15Gy) incubation at 37℃ the DNA single strand breakscould be rejoined but incompletely. The rejoined strands broke again if the cells wereincubated longer. The repair ratio of single strand breaks in the lymphocytes stimu-lated with PWM was the highest among the cells with three mitogens. The resultssuggest that the difference of the radiation effect on transformation in different lyt-phocytes is probably related to the repair ability of DNA single strand breaks.