Development of an enhanced bovine viral diarrhea virus subunitvaccine based on E2 glycoprotein fused to a single chain antibodywhich targets to antigen-presenting cells

Bovine viral diarrhea virus (BVDV) is an important cause of economic losses world-wide. E2 is an immunodominant protein and a promising candidate to develop subunit vaccines.To improve its immunogenicity, a truncated E2 (tE2) was fused to a single chain antibody named APCH, which targets to antigen-presenting cells. APCH-tE2 and tE2 proteins were expressed inthe baculovirus system and their immunogenicity was firstly compared in guinea pigs. APCH-tE2 vaccine was the best one to evoke a humoral response, and for this reason, it was selected fora cattle vaccination experiment. All the bovines immunized with 1.5 µg of APCH-tE2 developedhigh levels of neutralizing antibodies against BVDV up to a year post-immunization, demon-strating its significant potential as a subunit vaccine. This novel vaccine is undergoing scale-upand was transferred to the private sector. Nowadays, it is being evaluated for registration asthe first Argentinean subunit vaccine for cattle.