Table 1

Intracellular Killing of T. gondii Tachzyoites by Thioglycollate Elicited, Peritoneal Cells from Noninfected C57BL/6 and iNOS ko Mice

In vitro stimulusTachyzoite/cell ratioC57BL/6iNOS KO
cpm% killingcpm% killing
INone     088 ± 4  130 ± 20
None     1  8602 ± 27747078 ± 697
IFN-γ     1883 ± 6190.7%5943 ± 121716.3%
IINone     0   61 ± 36  31 ± 3
None0.24078 ± 7063288 ± 472
IFN-γ0.2335 ± 5194.1%3780 ± 378 0.0%
IFN-γ l-NMMA0.24352 ± 469     2.3%4525 ± 375 2.8%
None     110764 ± 16918117 ± 1084
IFN-γ     1   389 ± 11297.3%6849 ± 40516.0%
IFN-γ l-NMMA     19078 ± 660     0.0%7923 ± 34121.0%
  • Mice (3–5 per group) were injected intraperitoneally with sterile thioglycollate solution and 4–5 d later, the animals were killed and their peritoneal cells were isolated and pooled. The populations were then pretreated for 2 h with murine IFN-γ (100 U/ml) in the presence or absence of 2.5 mM l-NMMA. Cultures were subsequently infected with RH tachyzoites and 24 h later pulsed with 3H-uracil. Incorporated radioactivity was next determined and expressed as mean CPM ± SE for triplicate cultures. Percentage killing was then calculated using the formula indicated in Materials and Methods. The experiments shown are representative of five performed.