Recombinant peptides as new immunogens for the control of the bovine tick, Rhipicephalus (Boophilus) microplus.

A candidate vaccine that effectively controls Rhipicephalus microplus ticks in livestock is an attractive strategy in bovine management because of the expensive and labor-intensive treatment of animals with acaricides. However, the complex nature of ectoparasites has imposed restrictions on the development of such a vaccine, and its future efficacy is still under debate. Using Phage Display technology, we developed specific immunogens that mimic R. microplus tick antigens and were successfully validated by in vitro and in vivo assays. Nine peptides were used in the experimental vaccination of mice and cattle with different formulations. The peptides generated specific antibody response against R. microplus larval proteins in mouse immunization. A vaccine mixture of all nine selected phage clones was employed in cattle vaccination and the immune response induced specific changes in teleogine physiology, manifested as a hemorrhagic event in the gastrointestinal and reproductive tracts. A new means for vaccine development and the discovery of immunogens have been demonstrated, and our data may provide evidence that a putative vaccine for ectoparasite control is possible.