title: Immunolocalization and characterization of the low molecular weight antigen (4-5 kDa) of Toxoplasma gondii that elicits an early IgM response upon primary infection.
abstract: A striking feature of toxoplasmic seroconversion is the prominent and early IgM response to a low molecular weight antigen of 4-5 kDa. Two different monoclonal antibodies directed against the 4-5 kDa antigen have been generated and used to characterize this molecule. Using these monoclonal antibodies, we could demonstrate the surface localization of the low M(r) antigen by immunofluorescence and immuno-electron microscopy assays. By immunoblotting, we observed that one of the monoclonal antibodies was unable to recognize the 4-5 kDa antigen in tachyzoites propagated in cell culture, indicating an epitope variability between Toxoplasma gondii tachyzoites grown in vivo and in vitro. We discuss the implications of this latter finding in the design of diagnostic reagents.
authors.affiliation: U.42, Institut National de la Santé et de la Recherche Médicale, Villeneuve d'Ascq, France.
authors.forename: S
authors.initials: S
authors.lastname: Tomavo
authors.forename: G
authors.initials: G
authors.lastname: Couvreur
authors.forename: M A
authors.initials: MA
authors.lastname: Leriche
authors.forename: A
authors.initials: A
authors.lastname: Sadak
authors.forename: A
authors.initials: A
authors.lastname: Achbarou
authors.forename: B
authors.initials: B
authors.lastname: Fortier
authors.forename: J F
authors.initials: JF
authors.lastname: Dubremetz
mesh_terms: D000328:Adult; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000913:Antibodies, Protozoan / Q000096:biosynthesis*; D000940:Antigenic Variation; D000953:Antigens, Protozoan / Q000032:analysis* / Q000737:chemistry / Q000276:immunology; D000954:Antigens, Surface / Q000032:analysis / Q000737:chemistry / Q000276:immunology; D015153:Blotting, Western; D000939:Epitopes / Q000032:analysis / Q000276:immunology; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007075:Immunoglobulin M / Q000096:biosynthesis*; D051379:Mice; D016253:Microscopy, Immunoelectron; D008970:Molecular Weight; D011247:Pregnancy; D014122:Toxoplasma / Q000276:immunology* / Q000648:ultrastructure; D014124:Toxoplasmosis, Animal / Q000276:immunology*; D014709:Vero Cells
chemical_list: D000911:Antibodies, Monoclonal; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D000939:Epitopes; D007075:Immunoglobulin M