title: Analysis of structures and epitopes of surface antigen glycoproteins expressed in bradyzoites of Toxoplasma gondii.
abstract: Toxoplasma gondii is a protozoan parasite capable of infecting humans and animals. Surface antigen glycoproteins, SAG2C, -2D, -2X, and -2Y, are expressed on the surface of bradyzoites. These antigens have been shown to protect bradyzoites against immune responses during chronic infections. We studied structures of SAG2C, -2D, -2X, and -2Y proteins using bioinformatics methods. The protein sequence alignment was performed by T-Coffee method. Secondary structural and functional domains were predicted using software PSIPRED v3.0 and SMART software, and 3D models of proteins were constructed and compared using the I-TASSER server, VMD, and SWISS-spdbv. Our results showed that SAG2C, -2D, -2X, and -2Y are highly homologous proteins. They share the same conserved peptides and HLA-I restricted epitopes. The similarity in structure and domains indicated putative common functions that might stimulate similar immune response in hosts. The conserved peptides and HLA-restricted epitopes could provide important insights on vaccine study and the diagnosis of this disease.
authors.affiliation: Department of Human Parasitology, School of Medicine, Shandong University, No 44 Wenhuaxi Road, Jinan, Shandong 250012, China. conghua@sdu.edu.cn
authors.forename: Hua
authors.initials: H
authors.lastname: Cong
authors.forename: Min
authors.initials: M
authors.lastname: Zhang
authors.forename: Qingli
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jing
authors.initials: J
authors.lastname: Gong
authors.forename: Haizi
authors.initials: H
authors.lastname: Cong
authors.forename: Qing
authors.initials: Q
authors.lastname: Xin
authors.forename: Shenyi
authors.initials: S
authors.lastname: He
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000737:chemistry* / Q000276:immunology; D000954:Antigens, Surface / Q000737:chemistry / Q000276:immunology; D000939:Epitopes / Q000737:chemistry / Q000276:immunology; D006023:Glycoproteins / Q000737:chemistry / Q000276:immunology; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D010455:Peptides / Q000276:immunology; D015800:Protozoan Proteins / Q000737:chemistry* / Q000276:immunology; D014122:Toxoplasma / Q000737:chemistry* / Q000276:immunology / Q000472:pathogenicity; D014123:Toxoplasmosis / Q000276:immunology / Q000469:parasitology*
chemical_list: D000953:Antigens, Protozoan; D000954:Antigens, Surface; D000939:Epitopes; D006023:Glycoproteins; D006680:HLA Antigens; D010455:Peptides; D015800:Protozoan Proteins; C067547:surface antigen P22, Toxoplasma