Monoclonal antibodies for the rapid diagnosis of influenza-B virus infections by ELISA: production and characterization.
BACKGROUND
Monoclonal antibodies directed against conserved epitopes of viral proteins have substantially improved the accuracy of several immunochemical methods in diagnostic virology.


OBJECTIVE
To characterize mouse monoclonal antibodies directed against structural protein antigens of influenza-B virus and evaluate their use as diagnostic reagents for the direct detection of such antigens in clinical specimens from patients with respiratory infections of unknown aetiology.


METHODS
(a) Production and characterization of monoclonal antibodies against influenza-B viral antigens, and (b) their use in two different ELISA systems for detecting influenza-B antigen either directly in clinical specimens or after confirmation by rapid culture in MDCK cells.


RESULTS
Four monoclonal antibodies were selected for their specificity for the nucleoprotein antigen as demonstrated by Western blot analysis. The specificity of these antibodies for different epitopes of the nucleoprotein was demonstrated by competition experiments, using unlabelled and biotin-labelled purified antibodies in a sandwich assay. All four antibodies belong to the mouse IgG(2a) isotype, lack haemagglutination inhibition and neutralization properties and exhibit titres as high as 10(-6) in ELISA with as little as 30 ng purified influenza-B virus. ELISA methods using these antibodies detected only influenza-B viral antigens in direct testing of clinical specimens from patients with known influenza-B or influenza-A infections, or after reisolating virus from such specimens in tissue culture of MDCK cells.


CONCLUSIONS
The antibodies were suitable for the direct detection and typing of influenza-B virus in clinical specimens or for use in rapid confirmation cultures.
Glikmann
G
G
Department of Virology, Statens Seruminstitut, Artillerivej 5, DK-2300 Copenhagen S, Denmark.
Chen
S N
SN
Mordhorst
C H
CH
Koch
C
C