Human trophoblast interferons: production and possible roles in early pregnancy.

Human villous and extravillous trophoblast populations were isolated from first- and third-trimester placentae and were stimulated with viral and non-viral inducers to produce interferons (IFNs). Polyriboinosinic/polyribocytidylic acid [poly(I:C)] induced exclusively IFN-beta in trophoblast cultures, whereas viruses induced mixtures of IFN-alpha subtypes and -beta. The level of IFN production was dependent on the trophoblast population, type of inducer and the stage of differentiation of the trophoblast. First-trimester extravillous trophoblast cultures produced greater than five-fold more IFN than third-trimester villous trophoblast on a per cell basis, whereas term syncytiotrophoblast produced twice as much IFN as term mononuclear villous trophoblast when stimulated with the same inducer. Pretreatment of trophoblast cultures with platelet-derived growth factor and granulocyte/macrophage-colony stimulating factor (GM-CSF) increased the trophoblast IFN production. Tandem high-performance affinity chromatography of the virus-induced trophoblast IFNs resulted in the isolation of trophoblast IFN-alpha and -beta with specific antiviral activities of 0.75-2.73 x 10(8) IU/ml protein. The trophoblast-induced IFNs have antiproliferative and immunosuppressive properties, and, furthermore, activated natural killer cell activity. These data may suggest the possible roles of these IFNs during embryonic development with regard to protection of the fetus against viral infection and maternal immunity.