Noncytopathic strains of bovine viral diarrhea virus prime bovine bone marrow-derived macrophages for enhanced generation of nitric oxide.

Bovine bone marrow-derived macrophages (BBMM) were infected in vitro with a cytopathic (cp) and a noncytopathic (ncp) biotype of bovine viral diarrhea virus (BVDV). The virus strains used, TGAN (ncp) and TGAC (cp), originate from one animal and are antigenically closely related. Both TGAC and TGAN infected a subset of BBMM. Only cp BVDV induced a cytopathic effect. Infection of BBMM resulted in the modulation of certain macrophage functions. Only ncp strains of BVDV primed BBMM for enhanced reactive nitrogen production in response to Salmonella dublin. In contrast, infection with both biotypes did not influence bacteria-induced procoagulant activity and both biotypes equally reduced PMA-induced superoxide production. This suggests that the two biotypes differentially and selectively affect certain macrophage functions related to host defense. For the first time, a BVDV biotype-associated difference has been related to a biochemical parameter of the host cell.