Anti-influenza antibody assay by light scattering.

A physical method based on light scattering at 90 degrees was used to make evident the specific interaction between influenza virus and influenza antiserum. Purified virus put in contact with different dilutions of normal chicken serum exhibited a dose-effect dependence, which was significantly different from that corresponding to the virus-antiserum interaction. The maximum dilution of anti-influenza rabbit serum allowing the detection of the specific interaction between serum and infected allantoic fluid was then established. This value was considered to represent the "light scattering titer" of the antiserum.