Immunity in vaccinated cattle exposed to experimental and natural infestations with Boophilus microplus

Gut membranes of the cattle tick Boophilus microplus were extracted using a low ionic strength buffer and the soluble antigens were used to vaccinate Hereford cattle. Following either experimental infestation with 40,000 larval ticks or exposure to field infestation, ticks from vaccinated cattle laid 54 and 75% fewer eggs, respectively, than ticks from control cattle. After cattle were given booster injections of vaccine, and either experimentally infested with 20,000 larval ticks or exposed to field infestation, the weight of eggs laid by ticks from vaccinated cattle was reduced by 80% and 52%, respectively. Acquired immunity to the ticks varied considerably in both vaccinated and non-vaccinated cattle.