Abstract:
Background: Rhipicephalus (Boophilus) spp. ticks economically impact on cattle production in
Africa and other tropical and subtropical regions of the world. Tick vaccines constitute a costeffective
and environmentally friendly alternative to tick control. The R. microplus Bm86 protective
antigen has been produced by recombinant DNA technology and shown to protect cattle against
tick infestations.
Results: In this study, the genes for Bm86 (R. microplus), Ba86 (R. annulatus) and Bd86 (R.
decoloratus) were cloned and characterized from African or Asian tick strains and the recombinant
proteins were secreted and purified from P. pastoris. The secretion of recombinant Bm86 ortholog
proteins in P. pastoris allowed for a simple purification process rendering a final product with high
recovery (35–42%) and purity (80–85%) and likely to result in a more reproducible conformation
closely resembling the native protein. Rabbit immunization experiments with recombinant proteins
showed immune cross-reactivity between Bm86 ortholog proteins.
Conclusion: These experiments support the development and testing of vaccines containing
recombinant Bm86, Ba86 and Bd86 secreted in P. pastoris for the control of tick infestations in
Africa.
