Detection of influenza virus by means of immune sera to MP and RNP inner proteins in solid phase radioimmunoassay

Solid phase radioimmunoassay (SPRIA) was shown suitable for detection of influenza virus in various biological materials using immune sera to membrane protein and ribonucleoprotein (RNP) isolated from strain A/USSR/90/77. Either serum was able to detect influenza A viruses with different hemagglutinins (H1,H3,H7) and did not react with influenza B viruses. SPRIA detected 0.3 ng viral protein per 1 ml, i.e., its sensitivity was 20 times higher than that of the hemagglutination test. Neither serum revealed the virus in the extract from choroallantoic membrane of infected chicken embryos. Competitive radioimmunoassay showed that the antigenic specificity of A/PR/8/34 virus RNP differed from that of A/USSR/90/77 virus RNP. (author)