Cloning and expression of the nucleoprotein of peste des petits ruminants virus in baculovirus for use in serological diagnosis.

Peste des petits ruminants (PPR) is a viral disease of goats and sheep characterized by erosive stomatitis, enteritis, and pneumonia. The virus is a member of the family Paramyxoviridae and the genus Morbillivirus. The disease has high morbidity and mortality rates and has a substantial economic impact in developing countries. We have cloned and sequenced the cDNA of the nucleocapsid (N) gene of the Nigeria 75/1 strain of PPR virus (PPRV). A comparison of its nucleotide and deduced amino acid sequence with those of the N gene of the tissue culture-attenuated strain of PPRV was performed. A divergence of 8.9 and 5.0% was found at the nucleotide and amino acid level, respectively. A recombinant baculovirus that expresses the N protein in insect cells and larvae (Spodoptera frugiperda) was generated. The recombinant protein, characterized by Western blot analysis, was shown to have a molecular weight of 58 kDa and was recognized by anti-PPRV antibodies. The recombinant protein was used successfully as a coating antigen in an enzyme-linked immunosorbent assay for the serological diagnosis of PPRV.