title: Minimal role for the circumsporozoite protein in the induction of sterile immunity by vaccination with live rodent malaria sporozoites.
abstract: Immunization with live Plasmodium sporozoites under chloroquine prophylaxis (Spz plus CQ) induces sterile immunity against sporozoite challenge in rodents and, more importantly, in humans. Full protection is obtained with substantially fewer parasites than with the classic immunization with radiation-attenuated sporozoites. The sterile protection observed comprised a massive reduction in the hepatic parasite load and an additional effect at the blood stage level. Differences in the immune responses induced by the two protocols occur but are as yet little characterized. We have previously demonstrated that in mice immunized with irradiated sporozoites, immune responses against the circumsporozoite protein (CSP), the major component of the sporozoite's surface and the leading malaria vaccine candidate, were not essential for sterile protection. Here, we have employed transgenic Plasmodium berghei parasites in which the endogenous CSP was replaced by that of Plasmodium yoelii, another rodent malaria species, to assess the role of CSP in the sterile protection induced by the Spz-plus-CQ protocol. The data demonstrated that this role was minor because sterile immunity was obtained irrespective of the origin of CSP expressed by the parasites in this model of protection. The immunity was obtained through a single transient exposure of the host to the immunizing parasites (preerythrocytic and erythrocytic), a dose much smaller than that required for immunization with radiation-attenuated sporozoites.
authors.affiliation: Laboratory of Malaria Immunology, Singapore Immunology Network, Agency for Science, Technology and Research (A*STAR), Biopolis, Singapore 138648, Singapore.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Mauduit
authors.forename: Rita
authors.initials: R
authors.lastname: Tewari
authors.forename: Nadya
authors.initials: N
authors.lastname: Depinay
authors.forename: Michèle
authors.initials: M
authors.lastname: Kayibanda
authors.forename: Eliette
authors.initials: E
authors.lastname: Lallemand
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Chavatte
authors.forename: Georges
authors.initials: G
authors.lastname: Snounou
authors.forename: Laurent
authors.initials: L
authors.lastname: Rénia
authors.forename: Anne Charlotte
authors.initials: AC
authors.lastname: Grüner
mesh_terms: D000818:Animals; D005260:Female; D007371:Interferon-gamma / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D008099:Liver / Q000469:parasitology; D008288:Malaria / Q000517:prevention & control*; D017780:Malaria Vaccines / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D010962:Plasmodium berghei / Q000235:genetics / Q000276:immunology*; D010967:Plasmodium yoelii / Q000235:genetics / Q000276:immunology*; D015800:Protozoan Proteins / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D034101:Sporozoites / Q000276:immunology
chemical_list: D017780:Malaria Vaccines; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan; D007371:Interferon-gamma