EFFECTS OF INFLUENZA-A NUCLEOPROTEIN ON POLYMORPHONUCLEAR NEUTROPHIL FUNCTION

Infection with influenza virus is commonly associated with polymorphon uclear neutrophil (PMNL) dysfunction and consequent secondary bacteria l pneumonia, A recently isolated human-derived protein that inhibits P MNL chemotaxis and oxidant production shows a striking homology to the influenza A nucleoprotein, In the present study, the effects of purif ied influenza A nucleoprotein on PMNL chemotaxis, oxidant production, degranulation, and calcium homeostasis were studied, Results of the st udy demonstrate that purified nucleoprotein inhibits PMNL chemotaxis a s well as superoxide production, In addition, purified nucleoprotein i nduces a rise in PMNL cytosolic calcium concentration in a manner simi lar to that demonstrated for crude influenza A lysates, In contrast, n o difference in FMLP-stimulated PMNL elastase or beta glucuronidase re lease was noted after exposure to nucleoprotein, These studies suggest that the influenza A nucleoprotein may account for some of the neutro phil defect associated with cellular infection by this virus.