LACK OF AUGMENTING EFFECT OF INTERFERON-GAMMA ON DENGUE VIRUS MULTIPLICATION IN HUMAN PERIPHERAL-BLOOD MONOCYTES

The effect of interferon-gamma (IFN-gamma) on dengue virus multiplicat ion in human peripheral blood monocytes was investigated. Enriched mon ocytes were treated with IFN-gamma and then infected with dengue virus type 2 either directly or in the presence of optimal infection-enhanc ing levels of antibodies. Pretreatment of monocytes from dengue-immmun e donors with 100 IU/ml of IFN-gamma caused 12- to 97-fold and 13- to 137-fold reduction of virus yields at 24 hr after infection in the abs ence and presence of an anti-flavivirus monoclonal antibody, respectiv ely. IFN-gamma also diminished virus yields when infection of monocyte s from a donor who lacked anti-dengue antibody was enhanced 40-fold. T he percentage of infected monocytes in IFN-gamma-pretreated cultures w as similarly reduced. Dominance of the antiviral effect of IFN-gamma i n monocytes is in contrast to an augmenting effect previously observed in the promonocytic cell line U937. (C) 1995 Wiley-Liss, Inc.