A novel accessory role of neutrophils in concanavalin A-induced hepatitis

Concanavalin A (Con A)-induced hepatitis has been investigated as a model of T cell-mediated liver injury, in which IFN-γ plays an essential role by inducing apoptosis of liver cells. Since a large number of neutrophils infiltrate into the liver in the model, the role of neutrophils was investigated in this study. Con A hardly caused liver injury in neutrophil-depleted mice, as assessed as to the plasma alanine aminotransferase level as well as histochemistry. Neutrophil-depleted mice also failed to produce IFN-γ. Intracellular IFN-γ staining revealed that, among liver leukocytes, T and NK cells but not neutrophils are the main producers of IFN-γ. Nylon wool-purified “T cells,” however, failed to produce IFN-γ in response to Con A in vitro, while the production was restored by the addition of neutrophils. Overall, this study suggests that neutrophils play a novel accessory role in IFN-γ production in Con A-induced hepatitis.