Demonstration of Antigenic Differences Between Different Strains of Influenza B

Abstract

The isolation of a new strain of influenza B virus, strain 572, is reported. The rate of adaptation of strain 572 to ferrets and mice was slow. This is consistent with previous reports that it is more difficult to isolate strains of influenza B than of influenza A. Quantitative antigenic differences between the Lee, TM, and 572 strains of influenza B virus were demonstrated by means of in vitro and mouse neutralization tests with specific immune sera. There was a close agreement between the results obtained by the two methods.