FACTORS INFLUENCING INACTIVATION OF INFECTIVITY AND HEMAGGLUTININ OF INFLUENZA VIRUS BY GAMMA RADIATION

Abstract

Factors influencing the effects of gamma, irradiation on influenza A(PR8) virus suspensions have been investigated. In purified virus suspensions in physiological saline, the hemagglutinin was destroyed more rapidly than the infectivity. The addition of reagents such as histidine, sodium p-aminohippurate, ascorbic acid, or cystine to the saline suspension reversed this effect. It was also found that the effect of a given amount of gamma radiation on the infectivity and hemagglutinin was similar regardless of whether the radiation was administered as a single dose or as two or four divided doses on different days. It is possible to calculate the amount of radiation required to destroy the infectivity and yet retain most of the hemagglutinin content, If a given dose of radiation has been insufficient to produce complete virus inactivation, the suspension can be subjected to a further dose, the amount of which can be exactly calculated, without destroying the hemagglutinin. These experiments were repeated with other strains of influenza A and B with similar results. The application of this work to the preparation of virus vaccines is being investigated and will be reported later.