Abstract: The vectors comprise a recombinant defective viral genome expressing at least one antigen suitable for the induction of systemic and secretory immune responses or an antibody conferring protection against an infectious agent. The defective viral genome comprises the genome of a parental virus having the viral replicase recognition signals located on ends 3? and 5?, further comprising internal deletions, and wherein said defective viral genome depends on a helper virus for its replication and encapsidation. These vectors are suitable for the forming of a recombinant system comprising the aforesaid expression vector, and a helper virus. The system is suitable for the manufacture of mono- and polyvalent vaccines against infectious agents of different animal species, especially pigs, dogs and cats, and as expression vehicles for antibodies protective against infectious agents.