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Traffic pathways of Plasmodium vivax antigens during intraerythrocytic parasite development
Carmen Bracho1, Irene Dunia, La Rosa Mercedes De
1Instituto Venezolano de Investigaciones Cientificas, Centro de Microbiologia y Biologia Celular, Caracas, Venezuela.
Abstract:
We investigated the secretory traffic of a Plasmodium vivax antigen (Pv-148) synthesised by the parasite during the blood cycle, exported into the host cell cytosol and then transported to the surface membrane of the infected erythrocyte. Studies of the ultrastructure of erythrocytes infected with P. vivax showed that intracellular schizogony is accompanied by the generation of parasite-induced membrane profiles in the erythrocyte cytoplasm. These structures are detectable soon after the parasite invades the erythrocyte and develop an elaborate organisation, leading to a tubovesicular membrane (TVM) network, in erythrocytes infected with mature trophozoites. Interestingly, the clefts formed stacked, flattened cisternae resembling a classical Golgi apparatus. The TVM network stained with the fluorescent Golgi marker Bodipy-ceramide. Specific immunolabelling showed that Pv-148 was transferred from the parasite to the erythrocyte surface membrane via the clefts and the TVM network. These findings suggest that the TVM network is part of the secretory pathways involved in parasite protein transport across the Plasmodium-infected erythrocyte and that Pv- 148 may represent a marker that links the parasite with the host cell cytoplasm and, in turn, with the extracellular milieu.
Insights
Researchers traced the journey of a Plasmodium vivax protein (Pv-148) from parasite synthesis to the infected red blood cell surface. A novel tubovesicular network (TVM) acts as a transport pathway for this malaria antigen.
Area of Science:
- Malariology
- Cell Biology
- Parasitology
Background:
- Plasmodium vivax causes malaria, infecting human erythrocytes.
- Parasite-secreted proteins are crucial for infection and pathogenesis.
- Understanding protein transport pathways is key to developing interventions.
Purpose of the Study:
- To investigate the secretory pathway of the Plasmodium vivax antigen Pv-148.
- To characterize the role of parasite-induced membrane structures in protein export.
- To determine how Pv-148 reaches the surface of infected erythrocytes.
Main Methods:
- Ultrastructural analysis of infected erythrocytes.
- Immunolabelling with specific antibodies against Pv-148.
- Staining with fluorescent Golgi markers (Bodipy-ceramide).
Main Results:
- Parasite-induced membrane profiles form a tubovesicular membrane (TVM) network within infected erythrocytes.
- The TVM network exhibits Golgi-like cisternae.
- Pv-148 is transported from the parasite to the erythrocyte surface via the TVM network.
Conclusions:
- The TVM network serves as a critical component of the secretory pathway in Plasmodium-infected erythrocytes.
- Pv-148 is a potential marker linking the parasite to the host cell and extracellular environment.
- This pathway is essential for parasite-host cell interaction and malaria pathogenesis.