title: Increased susceptibility to Toxoplasma gondii infection in SAG-1 transgenic mice.
abstract: SAG-1, one of the major surface proteins of Toxoplasma gondii, has been reported to play an important role in immune and pathogenic mechanisms of the parasites but its exact function is still unclear. We investigated the time courses of T. gondii infection in B6C3F1 transgenic mice carrying the SAG-1 gene. SAG-1 transgenic mice were infected intraperitoneally with a high virulent RH strain or a low virulent Beverley strain of T. gondii. When infected with RH strain tachyzoites, no significant differences in time courses of survivals between SAG-1 transgenic and wild-type mice were observed. Both groups succumbed to an acute infection within 8 days after infection. However, a lower survival rate (20%) was observed in SAG-1 transgenic mice than in wild-type (80%), when infected with Beverley strain cysts. This result indicates that SAG-1 transgenic mice are more susceptible to T. gondii infection as compared with their wild-type counterpart. ELISA using recombinant SAG-1 protein indicates that SAG-1 transgenic mice do not produce antibodies to the SAG-1 molecule. These findings may provide a critical tool for analysing the molecular mechanisms of pathogenesis and host immune responses during toxoplasmosis.
authors.affiliation: The Research Center for Protozoan Molecular Immunology, Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Seng
authors.forename: H
authors.initials: H
authors.lastname: Nagasawa
authors.forename: Y
authors.initials: Y
authors.lastname: Maki
authors.forename: M
authors.initials: M
authors.lastname: Yokoyama
authors.forename: N
authors.initials: N
authors.lastname: Inoue
authors.forename: X
authors.initials: X
authors.lastname: Xuan
authors.forename: I
authors.initials: I
authors.lastname: Igarashi
authors.forename: A
authors.initials: A
authors.lastname: Saito
authors.forename: K
authors.initials: K
authors.lastname: Fujisaki
authors.forename: T
authors.initials: T
authors.lastname: Mikami
authors.forename: N
authors.initials: N
authors.lastname: Suzuki
authors.forename: Y
authors.initials: Y
authors.lastname: Toyoda
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan; D004198:Disease Susceptibility; D051379:Mice; D008822:Mice, Transgenic; D015800:Protozoan Proteins / Q000235:genetics*; D014122:Toxoplasma / Q000276:immunology / Q000472:pathogenicity*; D014124:Toxoplasmosis, Animal / Q000209:etiology* / Q000276:immunology / Q000401:mortality
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; C047168:SAG1 antigen, Toxoplasma