Duration of immunity, efficacy and safety in sheep of a recombinant Taeniaovis vaccine formulated with saponin or selected adjuvants

The efficacy and safety of a recombinant Taenia ovis protein was tested in sheep using 13 different adjuvant formulations, including oil adjuvants, al uminium salts, saponin, Iscoms and DEAE-dextran. The oil adjuvants, saponin and DEAE-dextran gave the highest antibody responses and greatest degree o f protection against challenge infection with T. ovis eggs. Duration of imm unity studies with a saponin based vaccine showed that highly significant p rotection (>90% reduction of cyst numbers) was achieved when sheep were cha llenge infected one month after immunisation. Significant protection (79%) was still present when sheep were challenged 6 months after immunisation, T he optimum dose for this batch of saponin was 10 mg, which stimulated a pea k antibody titre of 38,400, 4 weeks after immunisation and did not cause in jection site reactions. Dialysed saponin was shown to retain its adjuvant p roperties and allowed an increase in dose to 30 mg without site reaction, r esulting in a peak antibody titre of 51,200. (C) 1999 Elsevier Science B.V. All rights reserved.