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Trypanosoma cruzi: shedding of surface antigens as membrane vesicles
M F Gonçalves1, E S Umezawa, A M Katzin
1Departamento de Bioquímica, Universidade de São Paulo, Brazil.
Abstract:
Tissue culture-derived trypomastigotes from Trypanosoma cruzi spontaneously shed surface antigens into the culture medium. The shedding is a temperature- and time-dependent phenomenon and is independent of the presence of proteins or immune serum in the medium. The analysis of this process in four strains (Y, YuYu, CA1, and RA) showed differences in the amounts of polypeptides released. However, for all strains the liberation of the entire set of surface polypeptides ranging in molecular mass from 70 to 150 kDa was observed. Biochemical and electron microscopic data strongly suggest that most of the surface antigens are released as plasma membrane vesicles, ranging from 20 to 80 nm in diameter.
Insights
Trypanosoma cruzi trypomastigotes shed surface antigens, primarily as plasma membrane vesicles. This shedding is temperature and time-dependent, releasing a full range of surface polypeptides across different strains.
Area of Science:
- Parasitology
- Cell Biology
- Molecular Biology
Background:
- Trypanosoma cruzi trypomastigotes are the infective stage of the parasite responsible for Chagas disease.
- The parasite's surface antigens play a crucial role in host-parasite interactions and immune evasion.
- Understanding antigen shedding is vital for developing diagnostic and therapeutic strategies.
Purpose of the Study:
- To investigate the phenomenon of surface antigen shedding by Trypanosoma cruzi trypomastigotes in vitro.
- To characterize the nature and extent of polypeptide release from different parasite strains.
- To elucidate the mechanism and physical form of antigen release.
Main Methods:
- Culturing Trypanosoma cruzi trypomastigotes from four different strains (Y, YuYu, CA1, RA).
- Analyzing shed polypeptides in the culture medium using biochemical methods.
- Employing electron microscopy to visualize the released structures.
Main Results:
- Trypanosoma cruzi trypomastigotes spontaneously shed surface antigens into the culture medium.
- Antigen shedding is dependent on temperature and time but independent of medium composition.
- All analyzed strains released the complete set of surface polypeptides (70-150 kDa), primarily as plasma membrane vesicles (20-80 nm in diameter).
Conclusions:
- The shedding of surface antigens by Trypanosoma cruzi is a significant biological process.
- Plasma membrane vesicles are the predominant form of antigen release.
- This shedding mechanism may have implications for parasite survival and host immune response modulation.