Aim: To observe the effect of IL-6 on the multiplication of Toxoplasma gondii.
Methods: Peritoneal macrophages from C57BL/6 mouse were incubated with 3H-uracil-labelled T. gondii in vitro.
Results: Pretreatment (but not post-treatment) of Mphi with IL-6 enhanced T. gondii multiplication in a dose-dependent manner. Pretreatment with IFN gamma resulted in active killing of parasites whereas the addition of IL-6 resulted in a partial reversal of IFN gamma-mediated toxoplasmacidal activity. Combining TNF alpha with IL-6 and IFN gamma pretreatment resulted in restoration of toxoplasmacidal activity. Addition of polyclonal anti-TNF alpha antibodies to IL-6 and IFN gamma pretreatment resulted in enhancement in the IL-6-mediated impairment of IFN gamma function.
Conclusion: IL-6 could enhance intraperitoneal multiplication of T. gondii and reverse IFN gamma-mediated toxoplasmacidal activity.