Targeting Cattle-Borne Zoonoses and Cattle Pathogens Using a Novel Trypanosomatid-Based Delivery System
(A-C) Quantification of anti-Bd37 antibody responses by ELISA assay demonstrate that calves exposed to Bd37 that is expressed at an internal (A) or surface location (B) on T. theileri, or is secreted (C), show sero-conversion (filled circles) within 12 weeks of inoculation. Animals that did not sero-convert are shown as open circles. (D) End-point titres measured for all experimental animals show that those cattle receiving secreted Bd37 achieved significantly higher antibody levels than the other treatment groups (* p<0.05, ** p<0.001). (E) Time-course of antibody response to secreted Bd37 vaccine vehicle in all cattle. (F) Sera from vaccinated animals are able to compete with an anti-Bd37 monoclonal antibody for ELISA binding; assay details are provided in the ‘Materials and Methods’. Vertical arrows in Panels C and E indicate inoculation of a further 1×106 transgenic T. theileri.