Conclusion
These results demonstrate that the structure of E2 molecules arranged in tandem and attached to an Fc fragment could represent a viable design for future vaccine candidates against BVD-MD.
Methods
The chimaeric protein was expressed in mammalian cell lines of different species by adenoviral transduction and purified by immobilised metal-affinity chromatography. The N-glycans were profiled by HPLC, and the BVDE2Fc immunogenicity was assessed in male mice. The antigen-antibody reactions were evaluated by ELISA.
Results
The MDBK cell line was selected from among five for the final production of BVDE2Fc. After purification to over 90%, the N-glycan profile showed neutral and complex oligosaccharides. The mouse immunisation induced a strong humoral response, which produced antibodies able to attach to conformational epitopes on E2 molecules, while the Fc fragment barely contributed to the immune response. Additionally, BVDE2Fc attached to antibodies from bovine sera positive to distinct BVD-MDV subtypes, whereas the loss of BVDE2Fc structure during the deglycosylation process considerably diminished those interactions.