title: The recombinant gut-associated M17 leucine aminopeptidase in combination with different adjuvants confers a high level of protection against Fasciola hepatica infection in sheep.
abstract: Fasciola hepatica M17 leucine aminopeptidase (FhLAP) is thought to play a role in catabolizing peptides generated by the concerted activity of gut-associated endopeptidases on host polypeptides, thus releasing amino acids to be used in protein anabolism. In this study, a recombinant functional form of this homo hexameric metallopeptidase produced in Escherichia coli was used in combination with adjuvants of different types in a vaccination trial in Corriedale sheep against experimental challenge with F. hepatica metacercariae. The experimental assay consisted of 6 groups of 10 animals; 5 of the groups (1-5) were subcutaneously inoculated at weeks 0 and 4 with 100 μg of rFhLAP mixed with Freund's complete plus incomplete adjuvant (group 1), Alum (group 2), Adyuvac 50 (group 3), DEAE-D (group 4) and Ribi (group 5); the adjuvant control group (group 6) received Freund's adjuvant. Two weeks after the booster, the sheep were orally challenged with 200 metacercariae. Immunization with rFhLAP induced significant reduction in fluke burdens in all vaccinated groups: 83.8% in the Freund's group, 86.7% in the Alum group, 74.4% in the Adyuvac 50 group, 49.8% in the Ribi group and 49.5% in the DEAE-D group compared to the adjuvant control group. Morphometric analysis of recovered liver flukes showed no significant size modifications in the different vaccination groups. All vaccine preparations elicited specific IgG, IgG1 and IgG2 responses. This study shows that a liver fluke vaccine based on rFhLAP combined with different adjuvants significantly reduced worm burden in a ruminant species that was high in animals that received the enzyme along with the commercially approved adjuvants Alum and Adyuvac 50.
authors.affiliation: Unidad de Biología Parasitaria, Departamento de Biología Celular y Molecular, Facultad de Ciencias, Instituto de Higiene, UdelaR. Av. A. Navarro 3051, CP11600 Montevideo, Uruguay.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Maggioli
authors.forename: Daniel
authors.initials: D
authors.lastname: Acosta
authors.forename: Fernando
authors.initials: F
authors.lastname: Silveira
authors.forename: Silvina
authors.initials: S
authors.lastname: Rossi
authors.forename: Sheila
authors.initials: S
authors.lastname: Giacaman
authors.forename: Tatiana
authors.initials: T
authors.lastname: Basika
authors.forename: Valeria
authors.initials: V
authors.lastname: Gayo
authors.forename: Diego
authors.initials: D
authors.lastname: Rosadilla
authors.forename: Leda
authors.initials: L
authors.lastname: Roche
authors.forename: José
authors.initials: J
authors.lastname: Tort
authors.forename: Carlos
authors.initials: C
authors.lastname: Carmona
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage*; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood; D000917:Antibody Formation; D005210:Fasciola hepatica / Q000201:enzymology / Q000276:immunology; D005211:Fascioliasis / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D007074:Immunoglobulin G / Q000097:blood; D007931:Leucyl Aminopeptidase / Q000276:immunology*; D008297:Male; D059208:Parasite Load; D011994:Recombinant Proteins / Q000276:immunology; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000517:prevention & control*; D034561:Sheep, Domestic / Q000276:immunology / Q000469:parasitology; D014611:Vaccination / Q000662:veterinary*; D014612:Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D000276:Adjuvants, Immunologic; D000909:Antibodies, Helminth; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D014612:Vaccines; D007931:Leucyl Aminopeptidase