Fractionation of the influenza virus with the object of producing subunit vaccine.

Attempts have been made to produce a subunit influenza vaccine containing haemagglutinin and neuraminidase but free of lipid and nucleic acid. Disintegration of virus with Nonidet P40 followed by selective dialysis was only partially successful, but by disintegration with sodium dodecyl sulphate followed by ether extraction and precipitation with ammonium sulphate a product was obtained in which the content of ribonucleic acid was reduced to 1% and the lipid content to less than 5% of the amounts present in the original virus. When Al strains of virus and some strains of virus A were shaken with n-butanol only the ribonucleoprotein (S antigen) was found in the aqueous phase and the procedure affords a very simple method of producing pure S antigen for use in serological diagnosis.