[Proteolytic enzymes and their inhibitors in experimental influenzal infection]

The evidence has been obtained indicating an increase in proteolysis in the lungs of mice within 1 1/2 - 2 1/2 hours and on the 2nd day after inoculation of the animals with 1X10(5)-1X10(6) LD50 of influenza AO/32 virus, whereas on the 5th day in the affected organ proteolysis was significantly reduced as compared to the controls. No significant differences in the levels of cateptic activity at pH 5.0 in the lungs of infected and noninfected animals were found at any intervals of the study. At 1 1/2--2 1/2 hours and 5 days postinfection the antitryptic activity of the serum was found to be increased. The increased proteolysis early in infection is considered to be a virus-induced process, while its decline on the 5th day postinfection may be of protective nature. The participation of the system of proteases and their inhibitors in influenza virus--sensitive cells interaction as well as in the pathogenesis of influenza pneumonia is suggested.