%0 Journal Article %A Sarkkinen, H. K. %A Halonen, P. E. %A Salmi, A. A. %T Type-specific Detection of Parainfluenza Viruses by Enzyme-immunoassay and Radioimmunoassay in Nasopharyngeal Specimens of Patients with Acute Respiratory Disease %D 1981 %J Journal of General Virology, %V 56 %N 1 %P 49-57 %@ 1465-2099 %R https://doi.org/10.1099/0022-1317-56-1-49 %K enzyme-immunoassay %K radioimmunoassay %K parainfluenza %K immunofluorescence %I Microbiology Society, %X SUMMARY A four-layer solid phase enzyme-immunoassay (EIA) and radioimmunoassay (RIA) techniques were applied for the type-specific detection of parainfluenza type 1, 2 and 3 virus antigens in sonicated nasopharyngeal specimens of patients with acute respiratory disease. Guinea-pig antiviral immunoglobulins on solid phase were used as the capture antibodies, rabbit antiviral immunoglobulins as the secondary antibodies, and horseradish peroxidase-labelled swine anti-rabbit immunoglobulins (EIA), or 125I-labelled sheep anti-rabbit IgG (RIA) as the indicator antibodies. A total of 174 nasopharyngeal specimens collected by mucus extractor were tested, and the results were compared with those obtained by a routinely used immunofluorescence (IF) technique. The same number of positive specimens were achieved by the EIA and the RIA and 3/4, 4/4 and 19/20 immunofluorescence (IF)-positive nasopharyngeal specimens were positive by the parainfluenza type 1, 2 and 3 immunoassays respectively. In addition, four parainfluenza type 1 and three parainfluenza type 3 virus-positive specimens were found by the immunoassays out of 146 parainfluenza IF-negative specimens. The type-specificities of the parainfluenza immunoassays were confirmed by showing that no cross-reactions occurred when purified immunizing antigens and the EIA-and RIA-positive clinical specimens were cross-tested. The results indicate that parainfluenza type-specific antigens can be detected directly in nasopharyngeal specimens by the immunoassays and the preliminary findings with a small number of positive specimens suggest that these assays have a diagnostic potential which is similar or slightly better than the IF techniques. %U https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-56-1-49