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trans-Sialidase from Trypanosoma cruzi binds host T-lymphocytes in a lectin manner
Adriane R Todeschini1, Murielle F Girard, Jean-Michel Wieruszeski
1Departamento de Bioquimica, Instituto de Biologia, 20551-013 Universidade do Estado do Rio de Janeiro, Brasil.
Abstract:
Trypanosoma cruzi, the protozoan parasite responsible for Chagas' disease, expresses on its surface an uncommon membrane-bound sialidase, known as trans-sialidase. trans-Sialidase is the product of a multigene family encoding both active and inactive proteins. We report here that an inactive mutant of trans-sialidase physically interacts with CD4(+) T cells. Using a combination of flow cytometry and immunoprecipitation techniques, we identified the sialomucin CD43 as a counterreceptor for trans-sialidase on CD4(+) T cells. Using biochemical, immunological, and spectroscopic approaches, we demonstrated that the inactive trans-sialidase is a sialic acid-binding protein displaying the same specificity required by active trans-sialidase. Taken together, these results suggest that inactive members of the trans-sialidase family can physically interact with sialic acid-containing molecules on host cells and could play a role in host cell/T. cruzi interaction.
Insights
Inactive trans-sialidase from Trypanosoma cruzi binds to CD43 on T cells. This interaction, mediated by sialic acid binding, suggests a role for inactive trans-sialidase in host-parasite interactions during Chagas' disease.
Area of Science:
- Parasitology
- Immunology
- Molecular Biology
Background:
- Trypanosoma cruzi causes Chagas' disease.
- Trans-sialidase is a surface enzyme encoded by a multigene family in T. cruzi.
- This family includes both active and inactive trans-sialidase proteins.
Purpose of the Study:
- To investigate the function of inactive trans-sialidase mutants.
- To identify host cell receptors for trans-sialidase.
- To understand the role of trans-sialidase in host-parasite interactions.
Main Methods:
- Flow cytometry to detect cell surface interactions.
- Immunoprecipitation to identify binding partners.
- Biochemical, immunological, and spectroscopic analyses to characterize binding properties.
Main Results:
- An inactive trans-sialidase mutant physically interacts with CD4(+) T cells.
- CD43 was identified as the counterreceptor for trans-sialidase on CD4(+) T cells.
- Inactive trans-sialidase binds sialic acid with the same specificity as active trans-sialidase.
Conclusions:
- Inactive trans-sialidase members can interact with sialic acid-containing molecules on host cells.
- These interactions may play a role in the host cell/T. cruzi interface.
- Inactive trans-sialidase represents a potential target for therapeutic intervention in Chagas' disease.