Influenza Virus Purification with the Zonal Ultracentrifuge

Abstract
Sufficient amounts of influenza virus (density, 1.185; size, 722 S ) can be highly purified (22,000 chicken cell agglutinating units per milligram of protein) with a zonal ultracentrifuge, used first in a rate process followed by isopycnic banding, to permit its detailed biological and physical-chemical evaluation.