Detection of Circulating Antigen with a MAb-Based Sandwich-ELISA and Its Comparison with Specific IgM Detection in Sera of Patients with Hemorrhagic Fever with Renal Syndrome

A monoclonal antibody (1H2) against nucleocapsid protein of Hantavirus was developed. A sandwich enzyme-linked immunosorbent assay (ELISA) with the monoclonal antibody (MAb) was established and evaluated for detecting circulating antigen (CAg) in serum of patients with hemorrhagic fever with renal syndrome (HFRS). Results were compared to that of an immunoglobulin M (IgM)-detecting ELISA. Of 143 patients with HFRS, 106 were positive for CAg of Hantavirus and 128 positive for specific IgM. Among the 15 HFRS patients in whom specific IgM was not detected, 10 were positive for CAg. Of 100 controls including 40 hepatitis B cases, 40 measles cases, and 20 healthy persons all were negative for both CAg and specific IgM. Detection of Hantavirus CAg with a MAb-based sandwich ELISA (MBS-ELISA) established in the present study adds a new diagnostic tool for HFRS, and it increases the diagnostic rate to conventional specific IgM detection, especially for patient in the early stage of HFRS.