PRECIPITIN REACTIONS OF HIGHLY PURIFIED INFLUENZA VIRUSES AND RELATED MATERIALS.

Antisera to purified PR8 virus, to purified protein from normal allantoic fluid, and to purified normal mouse lung particles were obtained from hyper-immunized rabbits and used in quantitative precipitin tests employing various purified preparations of influenza virus and related materials as antigens. The results of those tests indicated that the most highly purified preparations of PR8 or of Lee influenza virus obtained from infectious allantoic fluid contain an antigen characteristic of normal allantoic fluid and likewise that highly purified mouse lung PR8 virus contains an antigen characteristic of normal mouse lungs. Since the infectivity of virus preparations which were ultracentrifugally and electrochemically homogeneous was precipitated by the appropriate antisera to normal antigens, it was concluded that the normal antigens constitute a part of the 100 mmicro particles with which influenza virus activity is at present deemed to be associated. It was estimated from quantitative precipitin data that the most highly purified preparations of PR8 and of Lee influenza viruses obtained from infectious allantoic fluid contain at least about 20 and 30 per cent, respectively, of an antigenic structure characteristic of the sedimentable protein of normal allantoic fluid.