Immunogenicity and antigenicity of the recombinant EMA-1 protein of Theileria equi expressed in the yeast Pichia pastoris

• Published in: Revista brasileira de parasitologia veterinaria Vol. 18; no. 2; pp. 1 - 4
• Main Authors: Nizoli, Leandro Q, Conceição, Fabrício R, Silva, Sérgio S, Dummer, Luana A, Santos, Jr, Alceu G, Leite, Fábio P L
• Format: Journal Article
• Language: English
• Published: Brazil Colégio Brasileiro de Parasitologia Veterinária 01-04-2009
• Subjects: Animals; Female; Mice; Mice, Inbred BALB C; PARASITOLOGY; Pichia - metabolism; Protozoan Proteins - biosynthesis; Protozoan Proteins - immunology; Recombinant Proteins - biosynthesis; Recombinant Proteins - immunology; Theileria; VETERINARY SCIENCES; vacina recombinante; recombinant vaccine; Theileria equi; Pichia pastoris; EMA-1
• ISSN: 0103-846X; 1984-2961; 1984-2961
• DOI: 10.4322/rbpv.01802001

The equine piroplasmosis caused by Theileria equi is one of the most important parasitic diseases of the equine, causing damage to animal health and economic losses. In T. equi, 2 merozoite surface proteins, equi merozoite antigen EMA-1 and EMA-2, have been identified as the most immunodominant antigens. This suggests that these antigens might be used as immunobiological tools. The EMA-1 of Theileria equi was cloned and expressed in the yeast Pichia pastoris. The transformed yeast was grown at high cell density, expressing up to 389 mg x L(-1) of recombinant protein. The protein was concentrated and detected in Dot blot. The recombinant product was antigenically similar to the native protein as determined using monoclonal antibodies, and polyclonal antibodies obtained from equines naturally infected with T. equi. The immunogenicity of rEMA-1 protein was demonstrated by IFAT using sera from recombinant-protein-immunized mice using aluminum hydroxide as adjuvant. All animals vaccinated with rEMA-1 developed a high specific antibody response. This results suggest that rEMA-1 expressed in P. pastoris might be a strong candidate to be used as an antigen for immune diagnostics as well as a vaccine antigen.