Characterization of monoclonal antibodies to Marburg virus nucleoprotein (NP) that can be used for NP-capture enzyme-linked immunosorbent assay

After the first documented outbreak of Marburg hemorrhagic fever identified in Europe in 1967, several sporadic cases and an outbreak of Marburg hemorrhagic fever have been reported in Africa. In order to establish a diagnostic system for Marburg hemorrhagic fever by the detection of Marburg virus nucleoprotein, monoclonal antibodies to the recombinant nucleoprotein were produced. Two clones of monoclonal antibodies, MAb2A7 and MAb2H6, were efficacious in the antigen-capture enzyme-linked immunosorbent assay (ELISA). At least 40 ng/ml of the recombinant nucleoprotein of Marburg virus was detected by the antigen-capture ELISA format. The epitope of the monoclonal antibody (MAb2A7) was located in the carboxy-terminus of nucleoprotein from amino acid position 634 to 647, while that of the MAb2H6 was located on the extreme region of the carboxy-terminus of the Marburg virus nucleoprotein (amino acid position 643-695). These monoclonal antibodies strongly interacted with the conformational epitopes on the carboxy-terminus of the nucleoprotein. Furthermore, these two monoclonal antibodies were reacted with the authentic Marburg virus antigens by indirect immunofluorescence assay. These data suggest that the Marburg virus nucleoprotein-capture ELISA system using the monoclonal antibodies is a promising technique for rapid diagnosis of Marburg hemorrhagic fever.