title: A novel Fasciola hepatica saposinlike recombinant protein with immunoprophylactic potential.
abstract: A member of the Fasciola hepatica saposinlike/NK-lysin protein family with lytic activity on human peripheral blood mononuclear cells and erythrocytes was recently described. The current study was designed to test the immunoprophylactic potential of this protein termed FhSAP-2 against infection with F. hepatica in rabbits. Two doses of 50 microg of recombinant FhSAP-2 (rFhSAP-2) emulsified in TiterMax were injected subcutaneously on the dorsal surface of 4 rabbits at 2-wk intervals. Four weeks after the second immunization, the rabbits were infected orally with 25 F. hepatica metacercariae. Four non-immunized-infected rabbits were used as controls. An enzyme-linked immunosorbent assay revealed high levels of antibodies to both rFhSAP-2 and F. hepatica excretory-secretory antigens by 2 wk after the first immunization, which were always significantly higher in immunized-infected rabbits than in control-infected rabbits. On the completion of the trial, vaccinated rabbits had 81.2% less flukes than controls. Moreover, F. hepatica egg counts in feces, as well as in bile collected from the gall bladders from vaccinated animals, were lower, 83.8 and 73%, respectively, compared with controls. The vaccinated rabbits also had significantly lower amounts of parasite antigen in stool and bile samples than controls. Last, evaluation of macroscopic liver lesions revealed that the rabbits vaccinated with rFhSAP-2 had milder lesions than the infected-control rabbits. These findings support the hypothesis that this novel rFhSAP-2 protein has immunoprophylactic potential against fascioliasis in rabbits including antifecundity and antipathology effects. This is the first report on experimental vaccination of rabbits against F. hepatica with a purified, defined, recombinant protein related to a member of the saposinlike protein family.
authors.affiliation: Laboratory of Parasite Immunology and Pathology, Department of Pathology and Laboratory Medicine, Suite 617-A, University of Puerto Rico School of Medicine, PO Box 365067, San Juan, Puerto Rico 00936-5067.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Espino
authors.forename: George V
authors.initials: GV
authors.lastname: Hillyer
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000909:Antibodies, Helminth / Q000096:biosynthesis / Q000097:blood; D000947:Antigens, Helminth / Q000032:analysis; D001646:Bile / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005210:Fasciola hepatica / Q000276:immunology*; D005211:Fascioliasis / Q000517:prevention & control*; D005243:Feces / Q000737:chemistry / Q000469:parasitology; D006023:Glycoproteins / Q000235:genetics / Q000276:immunology*; D007124:Immunoenzyme Techniques; D008099:Liver / Q000469:parasitology / Q000473:pathology; D008297:Male; D010270:Parasite Egg Count; D011817:Rabbits; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D049231:Saposins; D014614:Vaccines, Synthetic
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D006023:Glycoproteins; C483345:PSAP protein, human; D011994:Recombinant Proteins; D049231:Saposins; D014614:Vaccines, Synthetic