IFN gamma inhibits porcine reproductive and respiratory syndrome virus replication in macrophages

This study reports the effect of IFN gamma on the replication of porcine re productive and respiratory syndrome virus (PRRSV) in macrophages. Pretreatm ent with IFN gamma profoundly affected PRRSV replication in porcine macroph ages evaluated by reduction in titer and percentage of positive cells. The effect of IFN gamma on PRRSV replication was both dose-dependent and relate d to the time of exposure. The mechanism of action was not due to blocking virus attachment. The inhibitory effect on PRRSV replication in macrophages suggests that IFN gamma may play an important role in protection.