Identification and Characterization of P0 Protein as a Vaccine Candidate Against Babesia divergens, Blood Parasite of Veterinary and Zoonotic Importance

Abstract

The molecular identification and antigenic characterization of P0 protein in <i>Babesia divergens</i>, a blood parasite of veterinary and zoonotic importance, were carried out in this study for use in developing subunit vaccines against <i>B. divergens</i> infection. Recombinant protein encoding P0 (BdP0) was developed in <i>Escherichia coli</i>, and its antiserum was generated in mice for further molecular characterization. Anti-rBdP0 serum had a specific interaction with the corresponding legitimate <i>B. divergens</i> protein, as confirmed by Western blotting and indirect fluorescent antibody tests. ELISA was used to assess the immunogenicity of BdP0 in a group of 68 bovine field samples, and significant immunological reactivity was found in 19 and 20 positive samples of rBdp0 and <i>B. divergens</i> lysate, respectively. The <i>in vitro</i> growth of <i>B. divergens</i> cultures treated with anti-rBdP0 serum was significantly inhibited (<i>p</i> < 0.05). Furthermore, after 6 h of incubation with 2 mg/ml anti-rBdP0 serum, the ability of pre-incubated free merozoites to invade bovine erythrocytes was reduced by 59.88%. The obtained data suggest the possible use of rBdP0 as diagnostic antigen and may serve as a vaccine candidate against babesiosis caused by <i>B. divergens</i> either in animal or human.