Plasmodium invasion of mosquito cells: hawk or dove?: Response from Mota and Rodrı́guez

Hepatocyte invasion by Plasmodium sporozoites is mediated by invagination of the host plasma membrane to form a parasitophorous vacuole which surrounds the invading sporozoite, and within which the parasite will replicate. Our recent observations 1xMigration of Plasmodium sporozoites through cells before infection. Mota, M.M. et al. Science. 2001; 291: 141–144Crossref | PubMed | Scopus (275)See all References1 show that Plasmodium sporozoites have an alternative mechanism for entering cells. Sporozoites migrate through several cells in the host before stopping to replicate inside a hepatocyte 1xMigration of Plasmodium sporozoites through cells before infection. Mota, M.M. et al. Science. 2001; 291: 141–144Crossref | PubMed | Scopus (275)See all References1. During this migration, sporozoites breach the plasma membrane and exist freely in the cytosol of host cells. Finally, sporozoites stop to replicate and enter hepatocytes through the formation of a parasitophorous vacuole.In fact, both the sporozoite and ookinete stages of Plasmodium have been observed moving through host cells and both can be found in the cytosol of host cells without a surrounding parasitophorous membrane 1xMigration of Plasmodium sporozoites through cells before infection. Mota, M.M. et al. Science. 2001; 291: 141–144Crossref | PubMed | Scopus (275)See all References, 2xUltrastructure of in vitro cultured exoerythrocytic stage of Plasmodium berghei in a hepatoma cell line. Aikawa, M. et al. Am. J. Trop. Med. Hyg. 1984; 33: 792–799PubMedSee all References, 3xMolecular interactions between Anopheles stephensi midgut cells and Plasmodium berghei: the time bomb theory of ookinete invasion of mosquitoes. Han, Y.S. et al. EMBO J. 2000; 19: 6030–6040Crossref | PubMedSee all References, 4xRelease of malaria circumsporozoite protein into the host cell cytoplasm and interaction with ribosomes. Hugel, F.U. et al. Mol. Biochem. Parasitol. 1996; 81: 151–170Crossref | PubMed | Scopus (36)See all References, 5xDirect infection of hepatocytes by sporozoites of Plasmodium berghei. Shin, S.C. et al. J. Protozool. 1982; 29: 448–454Crossref | PubMedSee all References, 6xPenetration of the mosquito (Aedes aegypti) midgut wall by the ookinetes of Plasmodium gallinaceum. Torii, M. et al. J. Protozool. 1992; 39: 449–454Crossref | PubMedSee all References, 7xPlasmodium sporozoite interactions with macrophages in vitro: a videomicroscopic analysis. Vanderberg, J.P. et al. J. Protozool. 1990; 37: 528–536Crossref | PubMedSee all References, 8xInvasion in vitro of mosquito midgut cells by the malaria parasite proceeds by a conserved mechanism and results in death of the invaded midgut cells. Zieler, H. and Dvorak, J.A. Proc. Natl. Acad. Sci. U. S. A. 2000; 97: 11516–11521Crossref | PubMedSee all References. This parallel behavior of two distinct stages of Plasmodium raises the possibility that they share similar molecular mechanisms for disrupting host-cell plasma membranes and for traversing cells.Many of the cells traversed by sporozoites are able to reseal their plasma membrane and survive 1xMigration of Plasmodium sporozoites through cells before infection. Mota, M.M. et al. Science. 2001; 291: 141–144Crossref | PubMed | Scopus (275)See all References1, although some do die 1xMigration of Plasmodium sporozoites through cells before infection. Mota, M.M. et al. Science. 2001; 291: 141–144Crossref | PubMed | Scopus (275)See all References, 9xUltrastructural observations on the infection of rat liver by Plasmodium berghei sporozoites in vivo. Meis, J.F. et al. J. Protozool. 1983; 30: 361–366Crossref | PubMedSee all References. As suggested by Sinden and Billingsley (above), it is possible that not all midgut cells that are traversed by ookinetes die. Both the ookinete and the sporozoite must traverse physical cellular barriers in their hosts to reach their final sites of replication. Their ability to disrupt host-cell plasma membranes, and to migrate through these cells, is probably necessary to establish a successful infection in the host.