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[Study on invasibility and multiplication of Toxoplasma strains with different virulence toward Vero-cells]
1Department of Parasitology, Shanghai Second Medical University, Shanghai 200025.
Aim:
To investigate the pathogenic mechanisms of Toxoplasma strains with different virulence.
Methods:
Tachyzoites from 3 strains, Viz. RH, B36 and Fukaya strains, were challenged to in vitro cultivated Vero-cells. Systematic examinations on the earliest invasion time, the invasion rate and intracellular multiplication were performed under different cultivation conditions.
Results:
The tachyzoites of all the 3 strains invaded the host cells within a short period after inoculation. Invasion rates were all increased along with the prolonged duration of infection. The intracellular multiplication was found to be most active in RH strain, moderate in B36, and comparatively slow in Fukaya strains. Using purified tachyzoites freed from host debris and proteins and adding sufficient FCS in the medium may facilitate the invasion and subsequent multiplication of the parasite.
Conclusion:
Strain differences in pathogenicity to the host may be correlated to the genetically predetermined multiplication capabilities of the parasites after being invaded to the host cell, and that environmental factors may give certain impact on the invasibility of the parasite.
Insights
Toxoplasma gondii strain virulence varies, with RH strain showing the highest intracellular multiplication. Parasite multiplication capability and environmental factors influence Toxoplasma pathogenicity.
Area of Science:
- Parasitology
- Cell Biology
- Infectious Diseases
Background:
- Toxoplasma gondii is an opportunistic protozoan parasite.
- Virulence differences among T. gondii strains impact disease severity.
- Understanding strain-specific pathogenicity mechanisms is crucial for disease management.
Purpose of the Study:
- To investigate the pathogenic mechanisms of Toxoplasma gondii strains with differing virulence.
- To compare the invasion and intracellular multiplication capabilities of RH, B36, and Fukaya strains.
Main Methods:
- Tachyzoites from RH, B36, and Fukaya strains were used to infect Vero cells in vitro.
- Systematic examinations of invasion time, invasion rate, and intracellular multiplication were conducted.
- Experiments were performed under varied cultivation conditions to assess environmental impacts.
Main Results:
- All three T. gondii strains invaded host cells rapidly, with invasion rates increasing over time.
- Intracellular multiplication was highest in the RH strain, moderate in B36, and slowest in Fukaya.
- Optimized conditions, including purified tachyzoites and sufficient fetal calf serum (FCS), enhanced parasite invasion and multiplication.
Conclusions:
- Differences in T. gondii strain pathogenicity correlate with genetically determined intracellular multiplication capabilities.
- Environmental factors can influence the invasiveness of T. gondii tachyzoites.
- Strain-specific virulence is a key determinant of Toxoplasma pathogenesis.