title: Immunization and challenge shown by hamsters infected with Opisthorchis viverrini following exposure to gamma-irradiated metacercariae of this carcinogenic liver fluke.
abstract: Here we report findings to optimize and standardize conditions to attenuate metacercariae of Opisthorchis viverrini by ionizing radiation to elicit protective immune responses to challenge infection. Metacercariae were gamma-irradiated and the ability of irradiated metacercariae to prevent patent infection of challenge metacercariae in hamsters was determined, as well as their ability to induce a host antibody response. Metacercariae irradiated in a dose-dependent manner, with 3, 5, 10, 12, 20, 25 and 50 Gray, were used to infect Syrian golden hamsters by stomach gavage to ascertain the effect of irradiation on ability of the worms to establish infection. In addition, other hamsters were infected with metacercariae irradiated with 20-50 Gray, followed by challenge with intact/wild-type (non-irradiated) metacercariae to determine the protective effect as established by the numbers of adult flukes, eggs of O. viverrini in hamster faeces and anti-O. viverrini antibody titres. Significantly fewer worms were recovered from hamsters immunized with metacercariae irradiated at 20, 25 and 50 Gray than from control hamsters infected with intact metacercariae or 0 Gray, and the worms showed damaged reproductive organs. Faecal egg numbers were decreased significantly in hamsters immunized with 25 and 50 Gray metacercariae of O. viverrini. Moreover, hamsters administered metacercariae that were protected elicited a robust, specific anti-fluke immunoglobulin G response compared to control hamsters, suggesting a role for antibody in protection elicited by radiation-attenuated metacercariae.
authors.affiliation: Graduate School, Khon Kaen University,Khon Kaen40002,Thailand.
authors.forename: A
authors.initials: A
authors.lastname: Papatpremsiri
authors.affiliation: Department of Radiology,Faculty of Medicine, Khon Kaen University,Khon Kaen40002,Thailand.
authors.forename: P
authors.initials: P
authors.lastname: Junpue
authors.affiliation: Centre for Biodiscovery and Molecular Development of Therapeutics, Queensland Tropical Health Alliance Laboratory, James Cook University,Cairns, Queensland4878,Australia.
authors.forename: A
authors.initials: A
authors.lastname: Loukas
authors.affiliation: Department of Microbiology,Immunology and Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University,Washington,DC20037,USA.
authors.forename: P J
authors.initials: PJ
authors.lastname: Brindley
authors.affiliation: Department of Microbiology,Immunology and Tropical Medicine, and Research Center for Neglected Diseases of Poverty, School of Medicine and Health Sciences, George Washington University,Washington,DC20037,USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Bethony
authors.affiliation: Tropical Disease Research Laboratory, Department of Pathology, Faculty of Medicine, Khon Kaen University,Khon Kaen40002,Thailand.
authors.forename: B
authors.initials: B
authors.lastname: Sripa
authors.affiliation: Department of Parasitology,Faculty of Medicine, Khon Kaen University,Khon Kaen40002,Thailand.
authors.forename: T
authors.initials: T
authors.lastname: Laha
mesh_terms: D000818:Animals; D000909:Antibodies, Helminth / Q000276:immunology; D006224:Cricetinae; D005243:Feces / Q000469:parasitology; D005260:Female; D005720:Gamma Rays; D006801:Humans; D007114:Immunization; D008099:Liver / Q000469:parasitology; D008297:Male; D008647:Mesocricetus; D058488:Metacercariae / Q000254:growth & development / Q000276:immunology / Q000502:physiology / Q000528:radiation effects*; D009889:Opisthorchiasis / Q000382:microbiology / Q000469:parasitology*; D009891:Opisthorchis / Q000254:growth & development / Q000276:immunology* / Q000502:physiology / Q000528:radiation effects; D012098:Reproduction / Q000528:radiation effects
chemical_list: D000909:Antibodies, Helminth