GB660109A - Improvements in or relating to the treatment of allantoic fluid containing a propagated virus together with non-viral proteins to obtain the virus in purified and viable from for use in a vaccine - Google Patents

Abstract

660,109. Vaccines; purified virus. AMERICAN CYANAMID CO. Sept. 30, 1947 [Oct. 1, 1946], No. 26374/47. Class 81 (i). A virus, in purified and viable form for use in a vaccine, is obtained from the allantoic fluid in which it has been propagated by adding 15 to 40 per cent by volume of a water-miscible organic protein-precipitant, e.g. ethyl alcohol, methyl alcohol and acetone, to the fluid which has, or is adjusted to, a pH of 5.0 to 8.0 and ionic strength of 0.005 to 0.5, while maintaining the temperature below 5‹ C., coordinating the volume of precipitant, the pH value, the ionic strength and the temperature to effect selective precipitation of the virus in viable form and separating the precipitated virus from the supernatant fluid containing the non-viral proteins. The precipitated virus is suspended in an aqueous medium, preferably buffered, at a pH 5.0 to 8.0 and at an ionic strength of 0.005 to 0.5, and 15 to 40 per cent by volume of a water-miscible organic protein precipitant added while maintaining the temperature below 5‹ C. The virus precipitate may be removed by low speed centrifugation at a temperature below 5‹ C. Alternatively, the precipitate obtained at the first or subsequent precipitation stages may be suspended in an aqueous medium at the pH and ionic concentration previously stated and the resulting suspension subjected to low speed centrifugation to separate insoluble non-viral proteins and then to high speed centrifugation to separate the virus. The process is particularly applicable to the virus of influenza, equine encephalomyelitis, yellow fever, St. Louis encephalitis, Colorado tick fever, rabies, psittacosis, Rock Mountain spotted fever, epidemic and murine typhus, Q fever, Jap B encephalitis poliomyelitis and Newcastle virus.