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Updated: Sep 27, 2026
Forward Genetics Screens Using Macrophages to Identify Toxoplasma gondii Genes Important for Resistance to IFN-γ-Dependent Cell Autonomous Immunity
Published on: March 12, 2015
[Effect of IL-6 on the multiplication of Toxoplasma gondii]
1Central Lab., First Teaching Hospital, Bethune University of Medical Sciences, Changchun 130021.
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.
Insights
Interleukin-6 (IL-6) promotes Toxoplasma gondii multiplication in macrophages. IL-6 also reverses the parasite-killing effects of interferon-gamma (IFN-γ), impacting host immune response.
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Context:
- Toxoplasma gondii is an intracellular parasite that infects a wide range of hosts.
- Macrophages are key immune cells involved in controlling T. gondii infections.
- Interleukin-6 (IL-6) is a pro-inflammatory cytokine with complex roles in immunity.
Purpose:
- To investigate the direct effect of IL-6 on T. gondii replication within macrophages.
- To determine if IL-6 modulates the anti-parasitic activity of other cytokines like IFN-γ and TNF-α.
Summary:
- In vitro studies using murine macrophages demonstrated that IL-6 significantly enhances T. gondii multiplication in a dose-dependent manner.
- IL-6 pretreatment impaired the ability of IFN-γ to inhibit parasite growth, while TNF-α, in combination with IL-6 and IFN-γ, restored parasite-killing activity.
- Neutralizing TNF-α partially reversed the inhibitory effect of IL-6 on IFN-γ function.
Impact:
- IL-6 plays a crucial role in promoting T. gondii survival and replication within macrophages.
- Understanding IL-6's interaction with IFN-γ and TNF-α is vital for developing effective immunotherapies against toxoplasmosis.
- This research highlights the complex cytokine network regulating T. gondii infections.
