title: Protection against Fasciola gigantica infection in mice by vaccination with recombinant juvenile-specific cathepsin L.
abstract: Fasciola gigantica cathepsin L1H (FgCatL1H) is one of the major cathepsin L released by juveniles of F. gigantica to aid in the invasion of host's tissues. Due to its high sequence similarity with other cathepsin L (CatL) isoforms of late stage F. gigantica, it was considered to be a good vaccine candidate that can block all CatL-mediated protease activities and affect juveniles as well as adult parasites. In this study, recombinant proFgCatL1H protein expressed in yeast, Pichia pastoris, system was mixed with Freund's adjuvants and used to subcutaneously immunize mice that were later challenged with metacercariae of F. gigantica. The percentage of worm protection in the rproFgCatL1H-vaccinated mice compared to the non-immunized and adjuvant control mice were approximately 62.7% and 66.1%, respectively. Anti-rproFgCatL1H antisera collected from vaccinated mice reacted specifically with rproFgCatL1H and other cathepsin L isoforms of F. gigantica, but the antibodies did not cross react with antigens from other trematode and nematode parasites, including Eurytrema pancreaticum, Opisthorchis viverrini, Fischoederius cobboldi, Cotylophoron cotylophorum, Gigantocotyle explanatum, Paramphistomum cervi, and Setaria labiato-papillosa. The levels of IgG1 and IgG2a in mouse sera increased significantly at two weeks after immunization and were highest during the sixth to eighth weeks after immunization. The IgG1 level was higher than IgG2a at all periods of immunization, implicating the dominance of the Th2 response. The levels of IgG1 and IgG2a in the immune sera were shown to be strongly correlated with the numbers of worm recovery, and the correlation coefficient was higher for IgG1. The levels of serum aspartate aminotransferase and alanine transaminase were significantly lower in the sera of rproFgCatL1H-vaccinated mice than in the infected control mice indicating a lower degree of liver damage. This study demonstrated a high potential of FgCatL1H vaccine, and its efficacy is currently being studied in the larger economic animals.
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Faculty of Physical Therapy, Mahidol University, Phuttamonthon 4 Road, Salaya 73170, Nakhon Pathom, Thailand.
authors.forename: Veerawat
authors.initials: V
authors.lastname: Sansri
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand. Electronic address: krai.mee@mahidol.ac.th.
authors.forename: Krai
authors.initials: K
authors.lastname: Meemon
authors.affiliation: Department of Pathobiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Faculty of Allied Health Sciences, Burapha University, Long-Hard Bangsaen Road, Saen Sook Sub-district, Mueang District, Chonburi 20131, Thailand.
authors.forename: Narin
authors.initials: N
authors.lastname: Changklungmoa
authors.affiliation: Department of Pathobiology, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Faculty of Allied Health Sciences, Burapha University, Long-Hard Bangsaen Road, Saen Sook Sub-district, Mueang District, Chonburi 20131, Thailand.
authors.forename: Pornanan
authors.initials: P
authors.lastname: Kueakhai
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Pathanin
authors.initials: P
authors.lastname: Chantree
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand; Faculty of Veterinary Medicine, Mahanakorn University of Technology, Cheum-Sampan Road, Nong Chok, Bangkok 10530, Thailand.
authors.forename: Pannigan
authors.initials: P
authors.lastname: Chaichanasak
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Natcha
authors.initials: N
authors.lastname: Lorsuwannarat
authors.affiliation: Laboratory of Veterinary Parasitology, Faculty of Agriculture, Iwate University, Ueda 3-18-8, Morioka 020-8550, Japan.
authors.forename: Tadashi
authors.initials: T
authors.lastname: Itagaki
authors.affiliation: Department of Anatomy, Faculty of Science, Mahidol University, Rama VI Road, Bangkok 10400, Thailand.
authors.forename: Prasert
authors.initials: P
authors.lastname: Sobhon
mesh_terms: D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D002403:Cathepsins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D005209:Fasciola / Q000254:growth & development / Q000276:immunology*; D005211:Fascioliasis / Q000276:immunology* / Q000517:prevention & control*; D005620:Freund's Adjuvant; D007074:Immunoglobulin G / Q000097:blood; D007279:Injections, Subcutaneous; D008099:Liver / Q000473:pathology; D058488:Metacercariae; D051379:Mice; D010843:Pichia / Q000235:genetics; D011994:Recombinant Proteins / Q000008:administration & dosage / Q000276:immunology; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000008:administration & dosage* / Q000276:immunology*
chemical_list: D000909:Antibodies, Helminth; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D014614:Vaccines, Synthetic; D005620:Freund's Adjuvant; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase; D002403:Cathepsins; C509464:cathepsin L1, Fasciola hepatica
keywords: Cathepsin L1H; Fasciola gigantica; Juvenile fluke; Recombinant protein; Vaccine