Babesia bovis RON2 contains conserved B-cell epitopes that induce an invasion-blocking humoral immune response in immunized cattle
Por:
Hidalgo-Ruiz M., Suarez C.E., Mercado-Uriostegui M.A., Hernandez-Ortiz R., Ramos J.A., Galindo-Velasco E., León-Ávila G., Hernández J.M., Mosqueda J.
Publicada:
1 ene 2018
Resumen:
Background: Babesia bovis belongs to the phylum Apicomplexa and is the major causal agent of bovine babesiosis, the most important veterinary disease transmitted by arthropods. In apicomplexan parasites, the interaction between AMA1 and RON2 is necessary for the invasion process, and it is a target for vaccine development. In B. bovis, the existence of AMA1 has already been reported; however, the presence of a homolog of RON2 is unknown. The aim of this study was to characterize RON2 in B. bovis. Results: The B. bovis ron2 gene has a similar synteny with the orthologous gene in the B. bigemina genome. The entire ron2 gene was sequenced from different B. bovis strains showing > 99% similarity at the amino acid and nucleotide level among all the sequences obtained, including the characteristic CLAG domain for cytoadherence in the amino acid sequence, as is described in other Apicomplexa. The in silico transcription analysis showed similar levels of transcription between attenuated and virulent B. bovis strains, and expression of RON2 was confirmed by western blot in the B. bovis T3Bo virulent strain. Four conserved peptides, containing predicted B-cell epitopes in hydrophilic regions of the protein, were designed and chemically synthesized. The humoral immune response generated by the synthetic peptides was characterized in bovines, showing that anti-RON2 antibodies against peptides recognized intraerythrocytic merozoites of B. bovis. Only peptides P2 and P3 generated partially neutralizing antibodies that had an inhibitory effect of 28.10% and 21.42%, respectively, on the invasion process of B. bovis in bovine erythrocytes. Consistently, this effect is additive since inhibition increased to 42.09% when the antibodies were evaluated together. Finally, P2 and P3 peptides were also recognized by 83.33% and 87.77%, respectively, of naturally infected cattle from endemic areas. Conclusions: The data support RON2 as a novel B. bovis vaccine candidate antigen that contains conserved B-cell epitopes that elicit partially neutralizing antibodies. © 2018 The Author(s).
Filiaciones:
Hidalgo-Ruiz M.:
Immunology and Vaccines Laboratory, C. A. Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Carretera A Chichimequillas, Ejido Bolaños, Queretaro Queretaro, 76140, Mexico
Suarez C.E.:
Animal Disease Research Unit, USDA-ARS, P. O. Box 647030, Pullman, WA 99164-6630, United States
Mercado-Uriostegui M.A.:
Immunology and Vaccines Laboratory, C. A. Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Carretera A Chichimequillas, Ejido Bolaños, Queretaro Queretaro, 76140, Mexico
Hernandez-Ortiz R.:
CENID-Parasitologia Veterinaria, INIFAP, Carretera federal Cuernavaca-Cuautla #8534, Col. Progreso Jiutepec Morelos, 62550, Mexico
Ramos J.A.:
CENID-Parasitologia Veterinaria, INIFAP, Carretera federal Cuernavaca-Cuautla #8534, Col. Progreso Jiutepec Morelos, 62550, Mexico
Galindo-Velasco E.:
Facultad de Medicina Veterinaria y Zootecnia, Universidad de Colima, Km. 40 carretera Colima-Manzanillo, Tecoman Colima, 28100, Mexico
León-Ávila G.:
Departamento de Zoología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Carpio y Plan de Ayala, Col. Casco de Santo Tomás Mexico City, 11340, Mexico
Hernández J.M.:
Departamento de Biología Celular, Centro de Investigación y Estudios Avanzados, Instituto Politécnico Nacional, Av. IPN 2508, Col. San Pedro Zacatenco Mexico City, 07360, Mexico
Mosqueda J.:
Immunology and Vaccines Laboratory, C. A. Facultad de Ciencias Naturales, Universidad Autónoma de Querétaro, Carretera A Chichimequillas, Ejido Bolaños, Queretaro Queretaro, 76140, Mexico
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