Persistence of respiratory syncytial virus in macrophages alters phagocytosis and pro-inflammatory cytokine production

Functions of macrophage are known to be altered by acute infection with respiratory syncytial virus (RSV). However, it is unknown whether the persistent presence and expression of the RSV genome have any effect on the functions of these cells. We used a murine macrophage-like cell line (P388D₁) persistently infected with RSV to determine: (i) phagocytic activity mediated by Fcγ receptors, (ii) expression of Fcγ receptors, and (iii) production of IL-1β, IL-6 and TNF-α. Viral persistence was found to increase phagocytosis, expression of Fcγ receptors and the production of IL-1β and IL-6. In contrast the biological activity of secreted TNF-α decreased. In this study we give novel evidence that RSV persistence alters the biological activities of macrophages.