[Correlation between the dose and the anti-Toxoplasma effect of activated mouse macrophages induced by IFN-gamma and the synergism between IFN-gamma and TNF-alpha].
OBJECTIVE
To find out the dose dependence of the anti-Toxoplasma effect induced by IFN-gamma and to determine the possible synergistic activity between TNF-alpha and IFN-gamma.


METHODS
The in vitro effect of cultivated mouse peritoneal macrophages activated by IFN-gamma alone or IFN-gamma combined with different doses of TNF-alpha on the intracellular tachyzoites of RH strains and the nitric oxide (NO) level in the culture medium supernatant were simultaneously determined.


RESULTS
With the increase in the dose of IFN-gamma, the anti-Toxoplasma effect was augmented and the NO level was enhanced. At 24 hours after tachyzoite invasion, a significant reversed correlation was demonstrated between the NO level and the number of intracellular parasites.


CONCLUSIONS
The anti-Toxoplasma effect of macrophages activated by IFN-gamma appears to be dose-dependent and TNF-alpha acts synergitically with IFN-gamma in the activation of macrophages. The production of reactive NO could be an important effector in the IFN-gamma primed anti-Toxoplasma action.
Zhang
A
A
Laboratory of Parasitology, Shanghai Institute of Immunology, Shanghai 200025.
Yang
H
H
Yang
Y
Y
Qian
Z
Z
D000818:Animals; D002478:Cells, Cultured; D004357:Drug Synergism; D005260:Female; D007371:Interferon-gamma / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000276:immunology / Q000469:parasitology*; D051379:Mice; D009569:Nitric Oxide / Q000378:metabolism; D014122:Toxoplasma / Q000187:drug effects*; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D007371:Interferon-gamma