EARLY PULMONARY LESION IN THE CFW STRAIN MICE PRODUCED BY INTRAVENOUS INJECTION OF INFLUENZA VIRUS

Abstract

Mice of the CFW strain were more susceptible than the other strains of mice to the toxic effect of intravenously injected influenza virus (PR8 strain). Intravenous injection into the CFW mice with large amounts of fully infectious PR8 virus produced early haemorrhagic congestion in the lungs in addition to necrotic lesion in the liver and haemorrhage in the intestines. Histological study of the pulmonary lesion showed vascular engorgement, intra-alveolar haemorrhage, peribronchiolar and perivascular leucocyte infiltration, and bronchiolar and alveolar epithelial damage. It is hardly believable that this pulmonary lesion was the result of virus multiplication.
This early production of haemorrhagic congestion in the lungs of the CFW mice occurred also after intravenous injection of some toxic preparations having a markedly diminished or undetectable infectivity which were prepared by sonic disintegration of virus. In this case the pulmonary lesion was composed simply of vascular engorgement and intra-alveolar haemorrhage. However, on injection of the undiluted S fraction obtained from the sonically disrupted virus the pulmonary congestion was accompanied by moderate interstitial leucocyte infiltration.
From these histological findings it could be suggested that the production of bronchial and alveolar epithelial necrosis in the pulmonary lesion of theCFW mice depended upon the infective property of virus, the interstitial leucocyte infiltration upon the S antigen, and the interstitia capillary damage upon the toxic agent which is not responsible for infectivity and haemagglutination.