Antigen-capture ELISA for the detection of Rift Valley fever virus nucleoprotein using new monoclonal antibodies.

Monoclonal antibodies (MAbs) raised against the nucleoprotein (NP) of Rift Valley fever virus (RVFV) were developed, and an antigen-capture enzyme-linked immunosorbent assay (Ag-capture ELISA) system was developed for the detection of RVFV NP. The assay detected RVFV antigen from culture supernatants containing as little as 7.8-31.3 pfu per 100 μl. Reactivity with various truncated NPs indicated that MAb C10-54 bound only to the full-length NP, probably due to recognition of a conformational epitope, whereas MAbs G2-36 and D5-59 bound to a linear epitope ranging from amino acid residues 195-201 in the C-terminal region. Based on the alignments of the amino acid sequence of RVFV NP, the epitope regions of MAbs G2-36 and D5-59 were completely conserved among all RVFV strains. These results suggest that the MAbs are applicable to the Ag-capture ELISA for the diagnosis of RVFV infections.