Studies on the Intracellular Haemagglutinin Component of Fowl Plague Virus and other Myxoviruses

SUMMARY: In contrast to other members of the influenza virus group, a strain of fowl plague virus produced large amounts of intracellular haemagglutinin in the chorioallantoic membranes of infected chick embryos. The titres of intracellular haemagglutinin obtained with the fowl plague virus were 400-2000-fold higher than those of the human influenza viruses tested. The fowl plague virus also differed from the human influenza viruses in being capable of growing through the chorioallantoic membrane when inoculated by the chorionic route. The only other myxovirus so far discovered that elicited a high intracellular haemagglutinin titre was Newcastle disease virus, although this type of virus is neither serologically nor morphologically related to the influenza viruses.

Electron microscopic investigations of membrane specimens from embryos infected with fowl plague virus showed the presence of a large number of structures, ranging in size from 300 Å to more than 7000 Å, with a surface configuration indistinguishable from that of the envelope component of typical particles. Similar structures were found very rarely in specimens of membranes infected with the human influenza viruses.