Tunnelling Nanotube Projections May Interfere with Toxoplasma gondii Adhesion to Host Cells

Toxoplasma gondii, the causative agent of toxoplamosis, a disease widely distributed, is an intracellular parasite that invades host cells of different tissues using specialized endocytic activity. Recent studies suggest that tunneling nanotubes (TNTs), thin cell surface projections, may participate in the parasite-host cell interaction process. We report results on the involvement of host cells TNTs in the adhesion and internalization of T. gondii tachyzoites to epithelial LLC-MK² cells. Microscopy analysis showed that incubating cells in 0.45 M sucrose induces reversible assembly of TNTs without affecting cell viability. The presence of extended TNTs correlated with increase on parasite adhesion and reduction of parasite entry, suggesting a structural or signaling role in mediating adhesion. TNTs assembled following sucrose incubation contain both actin and tubulin components. These results highlight the functional relevance of TNTs in T. gondii host cell interaction, especially in parasite adhesion, opening new perspectives for understanding T. gondii-host cell interaction.