STUDIES OF CELLULAR DEFENSE AGAINST INFECTION: THE INTERACTION OF INFLUENZA VIRUS WITH PHAGOCYTIC CELLS AND ITS EFFECT ON PHAGOCYTOSIS

Abstract

Abstract : These studies are directed toward defining pathogenic mechanisms in combined infection by viruses and bacteria, especially acute bacterial respiratory infection complicating influenza. Of particular interest is the effect of virus upon phagocytic cells. The conclusions from the work of the past year are: Both influenza A and B viruses rapidly attached to exudative leukocytes of mice, rats, and guinea pigs. At physiological temperatures the WS strain of influenza A virus eluted from all of these cells except guinea pig macrophages; these macrophages ingested the virus. Both the NWS strain of influenza A and influenza B viruses were ingested by PMN and by macrophages of all three species. Once inside leukocytes, influenza virus was rapidly destroyed. Interaction with influenza virus reduced the function of phagocytic cells. The antiphagocytic activity was exerted upon exudative polymorphonuclear and mononuclear phagocytes and upon alveolar macrophages, and the extent of inhibition depended upon the quantity of virus and the duration of virus-cell interaction. There were, however, major differences between species; the phagocytic activity of guinea pig and mouse leukocytes was reduced by virus, but that of rat cells was unaffected. Influenza A virus had no effect upon the phagocytic activity of blood leukocytes of guinea pigs. Following incubation with influenza A virus human blood leukocytes also ingested pneumococci normally.