EVALUATION OF ANTIGENS OF FASCIOLA-GIGANTICA AS VACCINES AGAINST TROPICAL FASCIOLIASIS IN CATTLE

Vaccine trials were conducted in Brahman cross cattle evaluating the e fficacy of 4 native antigens purified from adult Fasciola gigantica fl ukes, and 1 recombinant F. gigantica antigen, as vaccines against trop ical fasciolosis. The antigens tested were native glutathione S-transf erase, cathepsin L, paramyosin, fatty acid binding protein (FABP), and a recombinant FABP expressed in E. coli, and were formulated in 1 or more of several adjuvants (Quil A, Squalene Montanide 80(R), MF59-100, Auspharm(R), NAGO, polylactoglycolide microspheres, Algammulin, DEAE, Freund's). Vaccination induced low, moderate or high antibody titres to the various antigens which were dependent on the adjuvant. Low but significant reductions in fluke burdens (31%, P < 0.026) and fluke wet weight (36%, P < 0.041) were only observed in cattle vaccinated with the native FABP in Freund's adjuvant. There was no correlation between total antibody titres to FABP and protection. The protection observed in cattle vaccinated with native FABP of F. gigantica supports the no tion that this class of proteins is a useful target for protection of animals against Fasciola and extends the efficacy of FABPs to the trop ical liver fluke. This is the first report of vaccination of cattle ag ainst F. gigantica with a purified protein. (C) 1997 Australian Societ y for Parasitology. Published by Elsevier Science Ltd.