Sensitization of Erythrocytes by Influenza Virus Antigen

Abstract

Summary The allantoic fluid of chick embryos infected with influenza virus A/PR8/34 possessed sensitizing activity which was detected using Boyden's passive hemagglutination test. The virus-specific antigen was revealed when antisera free of antibody to chicken proteins were used. Antisera obtained from rats immunized with influenza virus grown in chick embryos were found to detect the host-specific antigen. The sensitizing influenza virus antigen proved to be soluble but it did not appear to be identical with the complement-fixing S antigen. No cross-reactions in passive hemagglutination tests were found between A and B types of influenza virus, but A and A2 subtypes reacted in almost an identical manner. Allantoic fluid infected with influenza virus retained its sensitizing activity after heating for 30 min at 70°C, but lost it at 100°C. Treatment for 2 hr by pepsin and trypsin in concentrations less than 2% did not affect the sensitizing activity of infected allantoic fluid. The sensitizing factor of infected allantoic fluid did not dialyze under conditions of the study. The analysis of fractions recovered after ether disintegration of purified virus suggested the localization of sensitizing factor inside the virion. Failure to separate the sensitizing factor from the mixture of subunits in destroyed virus suspension was discussed.