Immunizing effect of vaccinia virus expressing the nucleoprotein of rinderpest virus on systemic rinderpest virus infection in rabbits.

A recombinant vaccinia virus (RVV) expressing the nucleoprotein (NP) of rinderpest virus (RPV) was examined in rabbits for the involvement of the NP protein in protection from the RPV infection. Despite their production of anti-NP antibody, the RVV-immunized rabbits succumbed to the RPV challenge, although there was a slight delay in the onset of disease after the low-dose challenge. On the other hand, the animals immunized with RVV expressing the hemagglutinin (H) protein of the RPV were completely protected. These results indicate that the NP protein might be not so effective as the H protein for the protection against viremic and systemic infection with RPV.