An investigation of antigenic drift of neuraminidases of influenza A (H1N1) viruses

Abstract

SUMMARY A newly developed lectin neuraminidase test (LNT) and a panel of mouse monoclonal and post-infection ferret antibodies have been used to analyse antigenic drift in N1 neuraminidases of influenza A viruses isolated between 1933 and 1957 and also between 1977 and 1980. Significant antigenic differences were detected among the ‘early’ (1933–57) viruses since the NA of viruses isolated one year apart could be distinguished serologically. The NA ofthe ‘re-emerged’ virus A/USSR/92/77 (H1N1) was antigenically related but not identical to influenza A viruses isolated in 1949 (A/Paris/49 (H1N1), A/Geneva/49 (H1N1)) which thus predates the previously observed antigenic similarity of A/USSR/77 with A/FW/50 (H1N1) virus.