Investigation of the immunological properties of the bovine viral diarrhea virus protein NS3 expressed by an adenovirus vector in mice.

Two replication-defective human adenovirus recombinants encoding the NS3 protein (p80) of bovine viral diarrhea virus (BVDV) under the control of a modified adenovirus major later promoter (BM5), rAdBM5/NS3, and human cytomegalovirus promoter (CMV5), rAdCMV5/NS3, were constructed. These two recombinant adenoviruses were tested for their expression of the NS3 protein in vitro in three different cell lines and also in vivo for the induction of BVDV-specific immune responses in mice. The recombinant adenoviruses containing two different promoters induced different levels of humoral responses to the NS3 protein. The rAdBM5/NS3 was used to vaccinate mice in order to evaluate the ability of the NS3 protein in the induction of cellular immune responses. The rAdBM5/NS3 did not cause a stimulation of cell proliferation but caused a very strong increase in production of IFN-gamma in murine mononuclear cells stimulated in vivo by BVDV strains of genotype 1 and 2.