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Trypanosoma cruzi: modulation of parasite-cell interaction by plasma fibronectin
Abstract:
Treatment of either rat peritoneal macrophages (RPM), cloned 3T3 fibroblasts (3T3FR) or Trypanosoma cruzi trypomastigote culture forms with human plasma fibronectin (huFN) enhanced their association with the untreated counterpart and this related to the concentration of huFN used. When treatment was performed at 4 degrees C, the enhancing effect of huFN on parasite-cell interaction was greater than that observed at 37 degrees C. This observation could be related to the indirect immunofluorescence antibody assay showing that a significant increase of fibronectin staining was observed on the cell and parasite surfaces upon incubation with huFN and that the extent of fibronectin staining was greater at 4 degrees C. Incubation of huFN-treated or nontreated parasites or cells with anti-huFN antibodies exerted an inhibitory effect on the parasite-cell association. The region of fibronectin that interacts with the trypomastigote surface is unknown. Inhibition experiments suggested that the domain of fibronectin which interacts with parasite surface receptors would probably be localized close to the NH2-terminal region of the molecule. Taken together, these results suggest that fibronectin may play a role in the binding of parasites to the vertebrate host cell surface.
Insights
Human plasma fibronectin (huFN) enhances parasite-host cell interactions, with greater effects observed at lower temperatures. Anti-fibronectin antibodies inhibit this association, suggesting fibronectin
Area of Science:
- Cell Biology
- Parasitology
- Biochemistry
Background:
- Trypanosoma cruzi is a protozoan parasite that causes Chagas disease.
- The interaction between T. cruzi and host cells is crucial for infection.
- Fibronectin is an extracellular matrix protein involved in cell adhesion.
Purpose of the Study:
- To investigate the role of human plasma fibronectin (huFN) in the association between Trypanosoma cruzi trypomastigotes and host cells.
- To determine the effect of fibronectin concentration and temperature on parasite-host cell binding.
- To identify the region of fibronectin involved in this interaction.
Main Methods:
- Treatment of rat peritoneal macrophages (RPM) and 3T3 fibroblasts with huFN.
- Incubation of parasites and cells with huFN at different temperatures (4°C and 37°C).
- Indirect immunofluorescence antibody assay to detect fibronectin on cell and parasite surfaces.
- Inhibition experiments using anti-huFN antibodies.
Main Results:
- huFN treatment enhanced the association between T. cruzi trypomastigotes and host cells (RPM, 3T3FR) in a dose-dependent manner.
- The enhancing effect of huFN was more pronounced at 4°C compared to 37°C.
- Increased fibronectin staining was observed on both parasite and cell surfaces after huFN treatment, with greater staining at 4°C.
- Anti-huFN antibodies significantly inhibited parasite-cell association.
- Inhibition experiments suggested the NH2-terminal region of fibronectin interacts with parasite surface receptors.
Conclusions:
- Fibronectin plays a significant role in the binding of Trypanosoma cruzi trypomastigotes to vertebrate host cells.
- Temperature influences the effectiveness of fibronectin in mediating parasite-host cell interactions.
- The NH2-terminal region of fibronectin is likely involved in the interaction with trypomastigote surface receptors.