Expression of the nucleocapsid protein of Dugbe virus and antigenic cross-reactions with other nairoviruses.

ABSTRACT

The small (S) RNA segment of Dugbe (DUG) virus (Nairovirus, Bunyaviridae) encodes a single protein, the nucleocapsid (N) protein, of M(r) 49.4 kDa. cDNA derived from the complete coding region for the N protein was cloned into Autographa californica nuclear polyhedrosis virus (AcNPV) under control of the polyhedrin promoter and used to infect Spodoptera frugiperda insect cells. Western blotting analysis using monoclonal antibodies demonstrated the production of DUG N protein in the infected cells. Monoclonal and polyclonal antibodies to the N protein of Crimean-Congo haemorrhagic fever (CCHF) virus were found to cross-react weakly with the baculovirus expressed DUG N protein by Western blotting. When used in an enzyme linked immunoassay (ELISA), the DUG N protein reacted with polyclonal mouse immune ascitic fluids raised against either CCHF or Hazara viruses (both members of the CCHF serogroup of nairoviruses). Cross-reactions between DUG virus (Nairobi sheep disease serogroup) and members of other nairovirus serogroups were not detected.