Macrophage-virus interaction during Con A-induced protection against Japanese encephalitis virus in infant mice

Eight to ten-day-old mice when inoculated i.p. with Concanavalin A yielded a large number of cells in the peritoneal exudate (PE), the majority of which belonged to the macrophage series. Con A-treated and untreated (control) mice were infected i.p. with Japanese encephalitis (JE) virus. The PE cells of Con A-treated mice showed a higher percentage and greater intensity of virus specific immunofluorescent cells as compared with the cells from control mice. No live virus was detected in the Con A-induced cells. However, traces of live virus were found in the cells of control mice, 3-6 hr after infection. In vitro, peritoneal macrophages from Con A-treated mice showed a higher uptake of the virus (83.3%) within 18 hr as compared to the cells from paraffin-treated mice (34%). The protection of Con A-induced mice to JE virus challenge by i.p. route could be due to increased uptake and subsequent inactivation of the JE virus in the peritoneal exudate cells.