Change of enzyme activities during the early stage of influenza virus infection

Abstract Intracellular activities of various hydrolytic enzymes were investigated in monkey kidney cells infected with the A NWS strain of influenza virus. At the early stage of infection, there was a significant decrease in the activity of β-D-galactosidase, α-D-mannosidase, N -acetyl-β-D-glucosaminidase, acid and alkaline phosphatase. The decrease was roughly proportional to the multiplicity of infection, and restored at 2 hr after the infection. Corresponding to this intracellular decrease, there was an increase in the activities of these enzyme outside the cells. The results suggested that these hydrolytic enzymes would be released from the cell membrane or the lysosomes near the membrane in the process of adsorption and penetration of the virus particles.