title: Apical membrane antigen 1 is a cross-reactive antigen between Neospora caninum and Toxoplasma gondii, and the anti-NcAMA1 antibody inhibits host cell invasion by both parasites.
abstract: The cross-reactive antigens of Neospora caninum and Toxoplasma gondii are important in the exploration to determine the common mechanisms of parasite-host interaction. In this study, a gene encoding N. caninum apical membrane antigen 1 (NcAMA1) was identified by immunoscreening of a N. caninum tachyzoite cDNA expression library with antisera from mice immunized with recombinant T. gondii apical membrane antigen 1 (TgAMA1). NcAMA1 was encoded by an open reading frame of 1695 bp, which encoded a protein of 564 amino acids. The single-copy NcAMA1 gene was interrupted by seven introns. NcAMA1 showed 73.6% amino acid identity to TgAMA1. Mouse polyclonal antibodies raised against the recombinant NcAMA1 (rNcAMA1) recognized a 69-kDa native parasite protein by Western blotting. Immunofluorescence analysis showed that NcAMA1 was localized to the apical end of tachyzoites. Two-dimensional electrophoresis and Western blotting indicated that an approximately 57-kDa cleavage product was released into the excretory/secretory products of N. caninum. Preincubation of free tachyzoites with anti-rNcAMA1 IgG antibodies inhibited the invasion into host cells by N. caninum and T. gondii. These results indicated that AMA1 is a cross-reactive antigen between N. caninum and T. gondii and a potential common vaccine candidate to control two parasites.
authors.affiliation: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555, Japan.
authors.forename: Houshuang
authors.initials: H
authors.lastname: Zhang
authors.forename: Muller K A
authors.initials: MK
authors.lastname: Compaore
authors.forename: Eung-goo
authors.initials: EG
authors.lastname: Lee
authors.forename: Min
authors.initials: M
authors.lastname: Liao
authors.forename: Guohong
authors.initials: G
authors.lastname: Zhang
authors.forename: Chihiro
authors.initials: C
authors.lastname: Sugimoto
authors.forename: Kozo
authors.initials: K
authors.lastname: Fujisaki
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Nishikawa
authors.forename: Xuenan
authors.initials: X
authors.lastname: Xuan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000913:Antibodies, Protozoan / Q000276:immunology*; D000953:Antigens, Protozoan / Q000235:genetics / Q000276:immunology*; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D003429:Cross Reactions; D006790:Host-Parasite Interactions; D008018:Life Cycle Stages; D008969:Molecular Sequence Data; D018688:Neospora / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D010802:Phylogeny; D015800:Protozoan Proteins / Q000235:genetics / Q000276:immunology; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000276:immunology; D017386:Sequence Homology, Amino Acid; D014122:Toxoplasma / Q000254:growth & development / Q000276:immunology* / Q000472:pathogenicity; D014709:Vero Cells
chemical_list: C506564:AMA1 protein, Toxoplasma gondii; D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins