Research Articles

Immunoglobulin M-capture biotin-streptavidin enzyme-linked immunosorbent assay for detection of antibodies to dengue viruses

A biotin-streptavidin system was adapted to an IgM-capture ELISA for detection of dengue antibodies in human sera. To develop this assay, high titers of antibodies to flavivirus were purified by ion-exchange chromatography (DEAE-cellulose) and labeled with biotin. Heavy chain-specific goat anti-human IgM was first bound to the wells of a polystyrene microtiter plate, followed by binding of IgM in test specimens, and the use of tetravalent dengue antigens (dengue 1-4), biotin-labeled anti-flavivirus IgG, and streptavidin-peroxidase conjugate. The sensitivity and specificity of the IgM-capture biotin-streptavidin ELISA (IgM-BS-ELISA) in acute sera were 83.3% of patients with dengue infection and 95.3% of nondengue-infected cases, respectively. The positive predictive value was 92.4% and the negative predictive value was 89.2%. The efficiency of test was 90.4%. In convalescent sera, the sensitivity and specificity of IgM-BS-ELISA were 100% and 92.6%, respectively. The predictive values of positive and negative results were 90.3% and 100%, respectively. The efficiency of test was 95.6%. The agreement rate of IgM-BS-ELISA and standard hemagglutination inhibition test was good: kappa (kappa) values were 0.79 for acute sera and 0.91 for convalescent sera. The correlation between two methods was quite good, with correlation coefficients (r) of 0.76 for acute sera and 0.85 for convalescent sera (P < 0.001). The results indicate that the IgM-BS-ELISA is highly sensitive, specific, simple to perform, and rapid.