Effect of low dose radiation on intracellular calcium and protein kinase C in lymphocytes.
It is first reported in the present paper that whole-body irradiation (WBI) with low dose X-rays could increase intracellular calcium ions ([Ca2+]i) and stimulate protein kinase C (PKC) activity of mouse lymphocytes. Following WBI of male Kunming mice with 75 mGy X-rays at a dose rate of 12.5 mGy/min the mobilization of [Ca2+]i with Con A in CD4+ and CD8+ Cells in the thymus and spleen was potentiated and the amplitude of [Ca2+]i mobilization in thymocytes in response to anti-CD3 monoclonal antibody increased with time from 4 to 24 h following low dose radiation. The PKC activity in the homogenate of spleen was markedly stimulated 12 h after WBI with 75 mGy, reaching its peak value at 24-48 h and coming down to lower than normal on day 7. However, the PKC activity in the separated T lymphocytes reached its peak value at 12 h and that in the B lymphocytes reached its peak value on day 4, both coming down to below control on day 7. The implications of this facilitation of signal transduction in T lymphocytes in the mechanism of immunoenhancement after low dose radiation were discussed.
MPH Radiobiology Research Unit, Norman Bethune University of Medical Sciences, Changchun, China.
S Z
SZ
Liu
X
X
Su
Z B
ZB
Han
Y C
YC
Zhang
J
J
Qi
D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000528:radiation effects*; D018414:CD8-Positive T-Lymphocytes / Q000528:radiation effects*; D002118:Calcium / Q000378:metabolism*; D003208:Concanavalin A / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D011493:Protein Kinase C / Q000378:metabolism*; D015290:Second Messenger Systems; D013154:Spleen / Q000276:immunology / Q000528:radiation effects; D013950:Thymus Gland / Q000276:immunology / Q000528:radiation effects
D003208:Concanavalin A; D011493:Protein Kinase C; D002118:Calcium