Distinction of influenza viruses of different host cell origin.

Influenza A viruses grown in different animal or human cells retain their antigenic make-up as tested by the usual immunological assays. With the aid of a Sambucus nigra (L.) extract containing its lectins the viruses can be distinguished after one single passage in a different cell type by a change in their hemagglutinating properties. Binding of such lectins to influenza viruses may be a means for a more subtle classification, relating to the host cell origin of the virus.