Abstract
Two distinct pathways of gamma interferon (IFN-γ) production have been found in mice infected with lactate dehydrogenase-elevating virus. Both pathways involve natural killer cells. The first is mostly interleukin-12-independent and is not controlled by type I interferons. The second, which is suppressed by type I interferons, leads to increased levels of IFN-γ production and requires the secretion of interleukin-12. This regulation of IFN-γ production by type I interferons may help to control indirect pathogenesis induced by this cytokine.