Synthetic peptide antigens induce antibodies to Taenia ovis oncospheres

Sheep immunised with the Taenia ovis recombinant 45W antigen are protected from infection with the parasite. Two peptides were synthesised corresponding to putative host-protective regions at the N- and C-termini of 45W. Sera from sheep immunised with 45W or related recombinant proteins reacted strongly with the N-terminal peptide. Approximately 40% of the antibody directed against 45WB/X, a truncated form of 45W, was found to be directed against the N-terminal peptide sequence. Sheep were immunised with the N- and C-terminal peptides alone or conjugated to a carrier protein. The N-terminal peptide was found to be highly immunogenic whereas the C-terminal peptide required conjugation to a carrier protein to be immunogenic. Antibodies raised against each of these immunogens crossreacted with the parent protein, 45WB/X, however, only antibodies specific for the N-terminal peptide were found to bind to antigens from the T. ovis oncosphere.