A comparison of DNA vaccines expressing the 45W, 18k and 16k host-protective antigens of Taenia ovis in mice and sheep

The immunogenicity of DNA vaccines encoding three different Taenia ovis hos t-protective antigens was compared in mice and sheep. DNA vaccines encoding the 45W, 18k and 16k antigens of T. ovis were constructed. The ability of DNA vaccines encoding the 45W and 18k genes to express antigen was confirme d by Western blotting of transfected Cos-7 cells. BALB/c mice were vaccinat ed intramuscularly with 45W, 18k or 16k DNA vaccines and the humoral immune response analysed by ELISA. DNA vaccines expressing 45W, 18k or 16k antige n were immunogenic in mice and generated significant titres of antigen-spec ific antibody. Intramuscular vaccination of outbred sheep with the T. ovis DNA vaccines generated significantly lower titres of 45W-specific antibody and failed to generate 18k or 16k-specific antibody. The findings of this s tudy show that each of the three T. ovis host-protective antigens are amena ble to delivery via DNA vaccines, and that the parameters governing the eff icacy of DNA vaccines in sheep require further investigation. (C) 2000 Else vier Science B.V. All rights reserved.