Interaction of plasma membranes with influenza virus. VII. Effect on 3',5'-cyclic adenosine monophosphate...

In chick embryo cells (CEC) and plasma membranes (PM) isolated therefrom, three forms of 3',5'-cyclic adenosine monophosphate (cAMP) phosphodiesterase (PDE) were demonstrated: (1) PDE activated only by Ca2+ (Ca-PDE); (2) PDE activated only by Mg2+ (Mg-PDE); and (3) PDE stimulated in the presence of 2 mM Mg2+ by low concentrations of Ca2+ (Ca-Mg-PDE). Purified influenza A virus, under suitable conditions, lowered the activities of these PDEs. The decrease was greater in samples incubated in the presence of adenosine triphosphate (ATP) than in those incubated in its absence.