Sensitive and specific monoclonal immunoassay for detecting yellow fever virus in laboratory and clinical specimens

A solid-phase radioimmunoassay (RIA) was developed for the detection of yellow fever (YF) virus in infected cell culture supernatant fluid and clinical samples. The test employed a flavivirus group-reactive monoclonal antibody attached to a polystyrene bead support and a radiolabeled type-specific antibody probe in a simultaneous sandwich RIA format. Optimal assay conditions specified a 16-h incubation at high temperature (45 degrees C). Monoclonal antibody to tetanus toxoid was added to the radiolabeled probe to inhibit nonspecific binding. The sensitivity of the assay for cell culture-propagated virus was 2.0 log10 50% mosquito infectious doses per 100 microliters or 100 pg of gradient-purified virion protein per 100 microliters. Specificity, assessed with human sera from 512 patients with liver diseases other than YF, including acute viral hepatitis, showed a false-positive rate of 0.0 to 0.6%. Sera from experimentally infected rhesus macaques containing greater than 3.0 log10 units/100 microliter of YF virus were positive by RIA. Sera and liver tissue from human patients were found to be positive.