A Chromatographic Procedure for the Purification of Influenza Virus

Owing to the difficulties of achieving consistently good recoveries of virus from allantoic fluid containing influenza virus by chromatography on calcium phosphate columns the factors determining optimum yield were systematically investigated. It was found that calcium phosphate prepared by precipitation at a controlled pH of 7·5 gave best results provided that eluting buffers were adjusted to the same pH. Although calcium phosphate fractions were still evidently contaminated with non-viral material, further purification could be obtained by chromatography in agarose-gel columns. It appeared that separation of the virus on these columns was probably achieved as a result of the binding of virus surface groups on to the gel. A minimum overall purification factor of about 800-fold was achieved.