Plant-produced viral bovine vaccines: what happened during the last 10 years?

Vaccination has proved to be an efficient strategy to deal with viral infections in both human and animal species. However, protection of cattle against viral infections is still a major concern in veterinary science. During the last two decades, the development of efficient plant-based expression strategies for recombinant proteins prompted the application of this methodology for veterinary vaccine purposes. The main goals of viral bovine vaccines are to improve the health and welfare of cattle and increase the production of livestock, in a cost-effective manner. This review explores some of the more prominent recent advances in plant-made viral bovine vaccines against foot-and-mouth disease virus (FMDV), bovine rotavirus (BRV), bovine viral diarrhoea virus (BVDV), bluetongue virus (BTV) and bovine papillomavirus (BPV), some of which are considered to be the most important viral causative agents of economic loss in cattle production.

Bovine respiratory syncytial virus infection in feedlot cattle cases in Argentina.

Although bovine respiratory syncytial virus (BRSV) infection has been reported in cattle in Argentina, it has not been associated with pneumonia in Argentina. We report here 5 cases of bovine pneumonia associated with BRSV. Autopsies were performed on 35 beef cattle with gross and/or microscopic lesions of pneumonia from 3 commercial feedlots. Lung samples in 5 of 35 animals were BRSV-positive by reverse-transcription nested PCR. The lungs of 2 of these 5 animals were coinfected with Mannheimia haemolytica, and 1 with bovine viral diarrhea virus 1. Microscopically, the lungs of 3 of the 5 BRSV PCR-positive animals had fibrinosuppurative bronchopneumonia, with or without pleuritis; 2 of the 5 had interstitial pneumonia. We conclude that BRSV is part of the bovine respiratory disease complex in Argentina.

Brucella spp. lumazine synthase as a bovine rotavirus antigen delivery system.

Brucella spp. lumazine synthase (BLS) is a highly immunogenic decameric protein. It has been previously evaluated as a carrier to increase the immunogenicity of peptides fused to its N-termini. VP8 is a sialic acid binding domain of rotavirus external capsid protein VP4, which is involved in virus adhesion to host cells. In this work, the C486 bovine rotavirus (BRV) VP8 core protein (VP8d) was fused to the structure of BLS with the aim to produce an enhancement of the immune response against BRV VP8 and to evaluate the possible use of this antigen for vaccine development. The feasibility of using BLS as an antigen delivery system of polypeptides larger in size than those previously tested was also evaluated. Groups of female mice were immunized with BLS-VP8d fusion protein, VP8d or an equimolar mixture of purified VP8d and BLS (BLS+VP8d). Dams immunized with BLS-VP8 induced 97.5-100% protection against homologous challenge with C486 BRV; while pups born to dams immunized either with VP8d or BLS+VP8d presented a significant lower level of protection. The neutralizing antibody pattern was also significantly different among these experimental groups, and in concordance with challenge experiment. Overall, these results demonstrate that the BLS-VP8d chimeric protein is properly folded and stable, and that the BLS scaffold is a potent antigen delivery system that enhances the antibody response against BRV and elicits complete homotypic passive protection in a suckling mouse model.