Polyethylene glycol purification of influenza virus with respect to aggregation and antigenicity.

Influenza virus may be precipitated and aggregated by polyethylene glycol into clusters comprising ten to many hundred virions per aggregate. These aggregates are sparingly soluble and may be freed of contaminating polymer by washing in the appropriate buffer at room temperature or by precipitation in 30% (v/v) ethanol at subzero temperatures.Immunogenic studies in guinea-pigs of the virus in different states of dispersion revealed that the aggregated virus is the superior antigen to the virus in the monomeric form or in the dissociated state following treatment with ether.