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Updated: May 10, 2026
Toxoplasma gondii Cyst Wall Formation in Activated Bone Marrow-derived Macrophages and Bradyzoite Conditions
Published on: August 12, 2010
Long-term investigations on Toxoplasma gondii-infected primary chicken macrophages
Irene Malkwitz1, Angela Berndt, Arwid Daugschies
1Institute of Parasitology, Centre for Infectious Diseases, Faculty of Veterinary Medicine, University Leipzig, An den Tierkliniken 35, 04103, Leipzig, Germany.
Abstract:
Toxoplasma (T.) gondii is known to infect various cell types including macrophages. In the present study, we generated monocyte-derived macrophage cultures from chicken blood. By flow cytometrical analysis, 84.5% of the cultivated cells showed typical macrophage properties. Macrophage cultures were cultivated at either 37 °C or 40 °C, respectively, and were infected 72 to 96 h post isolationem with tachyzoites of the T. gondii type II strain ME49 at a rate of 7.5 tachyzoites per host cell. Light microscopical investigations revealed incorporation of tachyzoites into the macrophages and gradual destruction of the infected macrophage culture. Parasite multiplication was observed by a quantitative real time PCR (qPCR) based on the 529-bp fragment specific for T. gondii. Samples were drawn 1 h post infectionem (p.i.), as well as 12, 24, 36, 48, and 72 h p.i. The parasite replication curve showed a transient decrease of parasite stages 12 h p.i. followed by a tachyzoite multiplication. The comparison of different culture conditions showed a significantly higher replication rate of T. gondii at 37 °C (median value 48 h p.i., 289.2% of the initial tachyzoite number) compared to cultures incubated at 40 °C (median value 48 h p.i., 73.1% of the initial tachyzoite number) throughout the observation period (P < 0.05). In general, replication rates were significantly lower than in a standard VERO cell cultures at 37 °C (P < 0.05). The observed differences were attributed to the physiological chicken macrophage reaction at 40 °C probably approximating the situation in vivo.
Insights
Chicken macrophages are susceptible to Toxoplasma gondii infection. T. gondii replicates better at 37°C than 40°C in these cells, suggesting temperature influences parasite growth in vivo.
Area of Science:
- Immunology
- Cell Biology
- Parasitology
Background:
- Toxoplasma gondii is an intracellular parasite with a broad host range.
- Macrophages are key immune cells involved in controlling parasitic infections.
- Understanding host-parasite interactions in avian species is crucial for controlling disease spread.
Purpose of the Study:
- To investigate the susceptibility of chicken monocyte-derived macrophages to T. gondii infection.
- To analyze the replication rate of T. gondii in chicken macrophages under different temperature conditions (37°C vs. 40°C).
- To compare T. gondii replication in chicken macrophages with that in standard cell lines.
Main Methods:
- Generation of chicken monocyte-derived macrophage cultures.
- Flow cytometrical analysis to confirm macrophage properties.
- Infection of macrophages with T. gondii tachyzoites (type II strain ME49).
- Quantitative real-time PCR (qPCR) to measure parasite replication at various time points post-infection.
- Cultivation of macrophages at 37°C and 40°C.
Main Results:
- Chicken macrophages were successfully cultured and exhibited typical macrophage characteristics.
- T. gondii tachyzoites infected and replicated within chicken macrophages, leading to culture destruction.
- Parasite replication was significantly higher at 37°C (289.2% increase) compared to 40°C (73.1% increase) at 48 hours post-infection.
- T. gondii replication rates were generally lower in chicken macrophages than in VERO cells at 37°C.
Conclusions:
- Chicken macrophages support T. gondii replication, demonstrating susceptibility to infection.
- Replication of T. gondii is temperature-dependent in chicken macrophages, with optimal growth at 37°C.
- The reduced replication at 40°C may reflect physiological host responses in chickens, approximating in vivo conditions.
