Search for Babesia bovis vaccine candidates.

Babesia bovis is a tick-borne apicomplexan pathogen that remains an important constrain for the development of cattle industries worldwide. Effective control can be achieved by vaccination with live attenuated forms of the parasite, but they have several drawbacks and thus the development of alternative subunit vaccines, either based in recombinant versions of full size proteins or in recombinant or synthetic peptides containing combinations of protective B-cell and T-cell epitopes is needed. Our current strategies for the identification of vaccine candidate antigens include the identification of functionally relevant antigens, bioinformatics, and comparative genomics using the recently sequenced B. bovis genome. These led us to the functional and immunological characterization of members of the VMSA gene family, a group of well conserved putative cysteine and serine proteases, and to the definition of a surface exposed B-cell epitope present in the Merozoite Surface Antigen-2c. Work in progress is focused in defining additional epitopes, and to determine whether they are neutralization-sensitive. These approaches might unravel useful vaccine candidates for B. bovis, and will increase our understanding of the pathogenicity mechanisms of these and related hemoparasites.