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Review: Toxoplasma gondii cellular invasion
A Bonhomme1, L Pingret, J M Pinon
1Unité INSERM U. 314, Reims, France.
Parassitologia
|December 1, 1992
Summary
Toxoplasma gondii invades host cells through a multi-step process involving specific molecular interactions and energy-dependent mechanisms. This parasite also modulates host immune responses by stimulating T cells and releasing key lymphokines like interferon-gamma and interleukin-2.
Area of Science:
- Parasitology
- Cell Biology
- Immunology
Background:
- Toxoplasma gondii is a widespread protozoan parasite responsible for toxoplasmosis.
- It necessitates an intracellular environment for its lifecycle, including growth and replication.
Purpose of the Study:
- To elucidate the detailed steps and molecular requirements of Toxoplasma gondii invasion into host cells.
- To understand the parasite's interaction with host immune cells, specifically T cell subsets.
Main Methods:
- The study describes the six-step invasion process of T. gondii.
- It highlights the roles of cellular recognition, parasite motility via cytoskeleton, cell adhesion, rhoptry secretion (including PEF, Ca++, and Ca++-activated ATPase), conoid penetration, and parasitophorous vacuole formation.
- Immune stimulation and lymphokine release (IFN-gamma, IL2) were also investigated.
Main Results:
- The invasion process is active, directed, and specific, influenced by factors such as energy sources, cations, and membrane properties.
- T. gondii actively induces the formation of a parasitophorous vacuole, essential for its survival and exchange within the host cell.
- The parasite effectively stimulates T cell subsets, leading to the release of crucial lymphokines.
Conclusions:
- Toxoplasma gondii employs a complex, regulated mechanism for host cell invasion.
- The parasite's interaction with the host immune system involves T cell activation and lymphokine production, contributing to the pathogenesis of toxoplasmosis.