Effect of dengue virus-induced cytotoxic factor on Fc-receptor functions of mouse macrophages

Many defects in macrophage functions in dengue type 2 virus (DV) infection have been shown to be mediated by production of the virus-induced cytotoxic factor (CF). An attempt has been made to determine whether the alterations in Fc-mediated functions of macrophages in DV-infected mice are due to CF. Mice given CF intravenously show a rapid fall in total numbers of peritoneal and spleen cells. The number of cells in the peritoneal cavity recovered in 48 h. but recovery in the spleen was not significant. The capacity of the splenic and peritoneal macrophages to attach and ingest opsonized sheep erythrocytes was significantly reduced, the lowest values of attachment index (AI) and phagocytic index (PI) being observed within 2-3 h. At later periods the AI values increased markedly but the PI values remained depressed. The effect was dose-dependent. The effect on Fc-receptor functions of macrophages in DV-infected mice thus appears to be mediated through CF.