title: Lifelong Persistence of Toxoplasma Cysts: A Questionable Dogma?
abstract: It is believed that infection by Toxoplasma gondii triggers a lifelong protective immunity due to the persistence of parasitic cysts which induce immunoprotection against reinfection. A review of the scientific literature since the 1950s did not yield any definitive data regarding the duration of cysts in the host or the presence of lifelong protective immunity, which led us to question this dogma. We put forward the hypothesis that sustained immunity to T. gondii requires repeated antigenic stimulations. The decline of seroprevalence recently observed in many countries might contribute to explain the loss of immunity. We address the potential consequences of this phenomenon, should it persist and worsen.
authors.affiliation: Hospices Civils de Lyon, Institut de Parasitologie et Mycologie Médicale, Hôpital de la Croix Rousse, F-69317 Lyon, France.
authors.forename: Solène
authors.initials: S
authors.lastname: Rougier
authors.affiliation: Department of Medicine and Division of Infectious Diseases, Stanford University School of Medicine, Stanford, CA 94305, USA; Palo Alto Medical Foundation Toxoplasma Serology Laboratory, Palo Alto, CA 94301, USA.
authors.forename: Jose G
authors.initials: JG
authors.lastname: Montoya
authors.affiliation: Hospices Civils de Lyon, Institut de Parasitologie et Mycologie Médicale, Hôpital de la Croix Rousse, F-69317 Lyon, France. Electronic address: francois.peyron@chu-lyon.fr.
authors.forename: François
authors.initials: F
authors.lastname: Peyron
mesh_terms: D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology; D001921:Brain / Q000469:parasitology; D003560:Cysts / Q000276:immunology*; D006790:Host-Parasite Interactions / Q000276:immunology*; D006801:Humans; D010506:Periodicals as Topic; D014122:Toxoplasma / Q000276:immunology*; D014123:Toxoplasmosis / Q000276:immunology*
chemical_list: D000913:Antibodies, Protozoan
keywords: lifelong immunity; premunition; toxoplasmosis