Location: Livestock Arthropod Pests Research
Project Number: 3094-32000-042-18-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2018
End Date: Jun 30, 2021
Long term assessment of immunity of cattle receiving Bm-86 vaccine through various administration protocols. This is a controlled field study with cattle in tick-free pasture conditions to assess and compare long-term immunity based on antibody titers against Bm86 antigen under field conditions. Two formulations of Bm86 vaccine will be used: Aqueous-based adjuvant (Zoetis-produced experimental serial of Bm86 Immunomodulator obtained from Texas Animal Health Commission) and Bm86 antigen formulated with an oil-based adjuvant (ZAF 003 also produced by Zoetis). Different vaccination schedules will also be assessed, with comparisons of more and less frequent vaccinations than the current recommended protocol for the aqueous Bm86 vaccine (Day 0, 28, 180). The study animals (n = 30) will be evenly distributed across 6 treatments in groups of 5 animals each. The experimental groups are as follows: (G1) Aqueous Bm86 (Bm86 Immunomodulator) - vaccinated on days 0, 28 and 180 (standard protocol); (G2) Aqueous Bm86 (Bm86 Immunomodulator) - vaccinated on days 0 and 180; (G3) Aqueous Bm86 (Bm86 Immunomodulator)- vaccinated on days 0, 28, 90, and 180; (G4) Oil based Bm86 (ZAF-003)- vaccinated on days 0, 28 and 180 (standard protocol); (G5) Oil based Bm86 (ZAF-003) - vaccinated on days 0 and 180; (G6) Oil based Bm86 (ZAF-003) - vaccinated on days 0, 90, and 180; the study will terminate at Day 210, when the cattle will be removed from the pasture.
Starting on day 0 and at the indicated timepoints throughout the study, animals will be briefly placed in a squeeze chute for blood collection that will be used to evaluate antibody responses to the Bm86 vaccine via ELISA. All procedures will be performed +/-2 days from the scheduled date to account for potential adverse weather conditions, given that the study is occurring outdoors. The study will evaluate any possible beneficial effect of different adjuvants in the formulations and intensity of immunizations on the persistence of immunity against Bm86 antigen.