A Comparison of Influenza Complement Fixation Antigens Derived from Allantoic Fluids and Membranes

Abstract

Summary A comparison was made of virus (V) and soluble (S) antigens derived from allantoic fluid and membrane of chick embryos infected with influenza A or B viruses. The antigens derived from membranes proved indistinguishable from the corresponding fractions prepared from allantoic fluid, as measured by serum cross-absorption and by complement fixing activity in the presence of convalescent and post-vaccination sera. Depending on the concentration of the inoculum, optimal titers of V and S antigens in the membranes were obtained in 24 to 48 hours, whereas they reached their highest titer in the fluid in 48 to 72 hours. The optimal sources for V were allantoic fluids harvested after 48 hours, whereas S was best prepared from membranes collected after incubation periods of 48 hours or less. The data presented indicate that complement-fixation tests with V from allantoic fluid and S from allantoic membrane represent reliable diagnostic tools.