title: Booster responses by oral vaccination with transgenic plants against chicken leucocytozoonosis.
abstract: We developed a transgenic potato (TrP/R7) expressing the recombinant R7 (rR7) antigen for use as an oral vaccine to protect against a chicken protozoan disease, chicken leucocytozoonosis. The TrP/R7 potato was produced by Agrobacterium tumefaciens-mediated transformation and regeneration, and the R7 gene insertion into potato chromosomes was confirmed by genomic polymerase chain reaction and Southern hybridization. rR7 antigen expression in TrP/R7 potato was also confirmed by sandwich enzyme-linked immunosorbent assay and western blotting using an antibody against the second-generation schizont of Leucocytozoon caulleryi. A transgenic potato clone with the highest rR7 antigen expression (3 µg rR7 antigen per gram of fresh-weight potato leaves) was selected, cultivated, and used in oral administration experiments to examine its ability to boost immunity. Chickens were immunized with chicken leucocytozoonosis vaccine "Hokken" by injection, and chickens that developed moderate levels of antibody titres were fed with TrP/R7 leaves. Chickens fed with TrP/R7 leaves showed increased antibody responses. In contrast, chickens fed with non-transgenic potato leaves showed a continuous decrease in antibody titres. Furthermore, chickens fed with TrP/R7 potato leaves showed strong resistance against experimental challenge with L. caulleryi infection. This study demonstrates the use of a plant-based oral vaccine to boost immunity against a protozoan disease.
authors.affiliation: Bioproduction Research Institute, National Institute of Advanced Industrial and Science Technology, Sapporo, Hokkaido, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ito
authors.forename: Tohru
authors.initials: T
authors.lastname: Gotanda
authors.forename: Naomi
authors.initials: N
authors.lastname: Himeno
authors.forename: Noriko
authors.initials: N
authors.lastname: Itchoda
authors.forename: Noriko
authors.initials: N
authors.lastname: Tabayashi
authors.forename: Kazunori
authors.initials: K
authors.lastname: Ike
authors.forename: Chihiro
authors.initials: C
authors.lastname: Sugimoto
authors.forename: Takeshi
authors.initials: T
authors.lastname: Matsumura
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D015139:Blotting, Southern / Q000662:veterinary; D015153:Blotting, Western / Q000662:veterinary; D002645:Chickens; D017931:DNA Primers / Q000235:genetics; D016787:Haemosporida; D007117:Immunization, Secondary / Q000662:veterinary*; D018515:Plant Leaves / Q000276:immunology; D030821:Plants, Genetically Modified / Q000737:chemistry*; D016133:Polymerase Chain Reaction / Q000662:veterinary; D011201:Poultry Diseases / Q000469:parasitology* / Q000517:prevention & control*; D011529:Protozoan Infections, Animal / Q000517:prevention & control*; D011198:Solanum tuberosum / Q000235:genetics; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000821:virology*
chemical_list: D000953:Antigens, Protozoan; D017931:DNA Primers; D014614:Vaccines, Synthetic