Effects of gamma-irradiation on intracellular proliferation of Toxoplasma gondii RH tachyzoites.
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.
Department of Parasitology, Seoul National University College of Medicine, Korea.
J
J
Kook
S H
SH
Oh
C K
CK
Yun
J Y
JY
Chai
D000818:Animals; D002455:Cell Division / Q000528:radiation effects; D002478:Cells, Cultured; D005720:Gamma Rays; D018922:HL-60 Cells / Q000469:parasitology; D006801:Humans; D008264:Macrophages / Q000469:parasitology; D051379:Mice; D008807:Mice, Inbred BALB C; D008813:Mice, Inbred ICR; D011829:Radiation Dosage; D014122:Toxoplasma / Q000166:cytology* / Q000528:radiation effects*