Related Experiment Video
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
[Anti-Toxoplasma effect of activated mouse macrophages induced by interferon-gamma combined with TNF-alpha]
1Department of Parasitology, Medical School, Shanghai Tiedao University, Shanghai 200331.
Aim:
To compare the inhibitory effect of the macrophages activated by IFN-gamma combined with TNF-alpha against RH strain and Fukaya strain.
Methods:
The average parasite proliferation rates of the two strains within the cytokine-activated M phi s were calculated at different times post-challenge, the nitric oxide (NO) levels in the medium supernatant were simultaneously determined.
Results:
In the macrophages activated by 100 U each of IFN-gamma and TNF-alpha, the invaded tachyzoites of RH strain were completely killed, while the invaded tachyzoites of Fukaya strain remained slow proliferation with significantly lower levels of NO detected at 24 h post challenge.
Conclusion:
The difference in the anti-Toxoplasma effect of the activated macrophages against RH and Fukaya strains might be attributed to the different amount of NO produced by the macrophages.
Insights
Activated macrophages effectively killed the RH strain of Toxoplasma gondii but only inhibited the Fukaya strain. This difference in anti-Toxoplasma effects may stem from varying nitric oxide (NO) production levels.
Area of Science:
- Immunology
- Parasitology
- Cell Biology
Context:
- Toxoplasma gondii poses a significant threat to immunocompromised individuals.
- Macrophages play a crucial role in the innate immune response against intracellular pathogens.
- Interferon-gamma (IFN-gamma) and Tumor Necrosis Factor-alpha (TNF-alpha) are key pro-inflammatory cytokines that activate macrophages.
Purpose:
- To investigate the differential inhibitory effects of cytokine-activated macrophages on two distinct strains of Toxoplasma gondii: RH and Fukaya.
- To compare the parasite proliferation rates and nitric oxide (NO) production in response to these strains.
Summary:
- Macrophages activated with IFN-gamma and TNF-alpha demonstrated complete clearance of the RH strain tachyzoites.
- In contrast, the Fukaya strain tachyzoites exhibited reduced proliferation, with significantly lower nitric oxide (NO) levels detected at 24 hours post-challenge.
- These findings suggest a strain-specific differential response of activated macrophages.
Impact:
- Highlights the varying susceptibility of different Toxoplasma gondii strains to macrophage-mediated immunity.
- Suggests that nitric oxide (NO) production is a critical factor in the differential anti-Toxoplasma activity.
- Informs potential therapeutic strategies targeting Toxoplasma gondii infections by considering strain-specific immune responses.
