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

Mohamed Abdo Rizk,Mohamad Alaa Terkawi,Mohamed Z Sayed-Ahmed,Mahmoud Aboulaila,Shimaa Sobhy Sorour,Shimaa Abd El-Salam El-Sayed,Haitham Eldoumani,Ikuo Igarashi

doi:10.3389/fvets.2021.795906

Abstract

The molecular identification and antigenic characterization of P0 protein in Babesia divergens, a blood parasite of veterinary and zoonotic importance, were carried out in this study for use in developing subunit vaccines against B. divergens infection. Recombinant protein encoding P0 (BdP0) was developed in Escherichia coli, and its antiserum was generated in mice for further molecular characterization. Anti-rBdP0 serum had a specific interaction with the corresponding legitimate B. divergens 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 B. divergens lysate, respectively. The in vitro growth of B. divergens cultures treated with anti-rBdP0 serum was significantly inhibited (p < 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 B. divergens either in animal or human.

Highlights

Despite numerous efforts, babesiosis is still one of the most infectious protozoan diseases worldwide
The present study investigated the molecular identification and antigenic characterization of the B. divergens ribosomal P0 protein in order to produce subunit vaccines to protect against B. divergens infection
The successful expression of cDNA for Bdp0 in E. coli was confirmed with sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE), and the rBdp0 had a molecular mass of 55 kDa (Figure 1A), including a 26-kDa glutathione S-transferase (GST) tag

Summary

Introduction

Babesiosis is still one of the most infectious protozoan diseases worldwide. In vitro studies have demonstrated that anti-P0 antiserum can neutralize Toxoplasma gondii, Neospora caninum, and Babesia bovis parasites by either inhibiting their growth or blocking cell invasion [20, 21], in addition to their role in the development of immunity against the malaria pathogen. Cell wall [17], whereas the P2 protein was localized on the surface of infected red blood cells at an early stage of the parasite development [17, 22]. Despite of their important role, the molecular characterization of P0 protein in B. divergens, a blood parasite of veterinary and zoonotic importance, has not been done yet. The present study investigated the molecular identification and antigenic characterization of the B. divergens ribosomal P0 protein in order to produce subunit vaccines to protect against B. divergens infection

Methods

Results

Conclusion