title: Alternative invasion pathways for Plasmodium berghei sporozoites.
abstract: Invasion of hepatocytes by Plasmodium sporozoites is a prerequisite for establishment of a natural malaria infection. The molecular mechanisms underlying sporozoite invasion are largely unknown. We have previously reported that infection by Plasmodium falciparum and Plasmodium yoelii sporozoites depends on CD81 and cholesterol-dependent tetraspanin-enriched microdomains (TEMs) on the hepatocyte surface. Here we have analyzed the role of CD81 and TEMs during infection by sporozoites from the rodent parasite Plasmodium berghei. We found that depending on the host cell type, P. berghei sporozoites can use several distinct pathways for invasion. Infection of human HepG2, HuH7 and HeLa cells by P. berghei does not depend on CD81 or host membrane cholesterol, whereas both CD81 and cholesterol are required for infection of mouse hepatoma Hepa1-6 cells. In primary mouse hepatocytes, both CD81-dependent and -independent mechanisms participate in P. berghei infection and the relative contribution of the different pathways varies, depending on mouse genetic background. The existence of distinct invasion pathways may explain why P. berghei sporozoites are capable of infecting a wide range of host cell types in vitro. It could also provide a means for human parasites to escape immune responses and face polymorphisms of host receptors. This may have implications for the development of an anti-malarial vaccine targeting sporozoites.
authors.affiliation: Inserm, U511, Hôpital Pitié-Salpêtrière, Université Pierre et Marie Curie-Paris 6, Faculté de Médecine Pitié-Salpêtrière, F-75013 Paris, France. olivier.silvie@med.uni-heidelberg.de
authors.forename: Olivier
authors.initials: O
authors.lastname: Silvie
authors.forename: Jean-François
authors.initials: JF
authors.lastname: Franetich
authors.forename: Claude
authors.initials: C
authors.lastname: Boucheix
authors.forename: Eric
authors.initials: E
authors.lastname: Rubinstein
authors.forename: Dominique
authors.initials: D
authors.lastname: Mazier
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000502:physiology*; D002460:Cell Line; D002784:Cholesterol / Q000502:physiology; D022781:Hepatocytes / Q000378:metabolism / Q000469:parasitology*; D006790:Host-Parasite Interactions; D006801:Humans; D008565:Membrane Proteins / Q000502:physiology; D051379:Mice; D010962:Plasmodium berghei / Q000469:parasitology / Q000472:pathogenicity*; D051381:Rats; D034101:Sporozoites / Q000502:physiology*; D060225:Tetraspanin 28; D059470:Tetraspanins
chemical_list: D015703:Antigens, CD; C554798:CD81 protein, human; C554799:Cd81 protein, mouse; D008565:Membrane Proteins; C508125:TSPAN1 protein, human; D060225:Tetraspanin 28; D059470:Tetraspanins; C486026:Tnmd protein, mouse; D002784:Cholesterol