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Effects of gamma-irradiation on intracellular proliferation of Toxoplasma gondii RH tachyzoites
Jina Kook,1Sung-Hee Oh,2Chong-Ku Yun,3 and Jong-Yil Chai*1
1Department of Parasitology and Institute of Endemic Diseases, Seoul National University College of Medicine, Seoul 110-799, Korea.
Received June 20, 1995; Accepted August 01, 1995.
Abstract
A quantitative assay was performed on the effects of gamma-irradiation (30-300 Gy) on intracellular proliferation of Toxoplasma gondii RH tachyzoites in human leukemic HL-60 cells and murine peritoneal macrophages by means of 3H-uracil uptake assay. Infected non-irradiation group (NI) and uninfected group (incubating only host cells) were prepared. The 3H-uracil uptake by tachyzoites of NI group 12-24 hrs after infection was 2,190-4,787 counts per minute for macrophages and 2,967-8,254 for HL-60 cells, whereas the irradiated tachyzoites revealed only 381-703 (100 Gy) and 218-408 (300 Gy) for macrophages, and 1,911-2,618 (30 Gy), 1,253-1,384 (70 Gy), 1,013-1,090 (100 Gy), and 483-588 (300 Gy) for HL-60 cells. The proliferation inhibition rate was similar in macrophages and HL-60 cells, for example, 89-94% and 80-94% respectively by 300 Gy, 12-24 hrs after infection. It is concluded that RH tachyzoites of T. gondii are severely affected by gamma-irradiation in their capability of intracellular proliferation.
Figures
Fig. 1 Inhibition of intracellular proliferation of T. goondii RH tachyzoites in murine peritoneal macrophages by gamma-irradiation. Percent(%) inhibition represents the extent of inhibition setting the uracil uptake (CPM) of non-irradiated (NI) group as 100%.
Fig. 2 Inhibition of intracellular proliferation of T. goondii RH tachyzoites in human leukemic HL-60 cells by gamma-irradiation. Percent(%) inhibition represents the extent of inhibition setting the uracil uptake (CPM) of non-irradiated (NI) group as 100%.
Tables
Table 1 3H-uracil uptake by T. goondii tachyzoites in murine peritoneal macrophages and HL-60 cells
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