Indeed, while the responses of some IFNs (skin IFNx2 and IFNL4; kidney IFN1) appear to be mediated by the cells that are present within the skin and kidney tissues of healthy animals, the drastic differences reported here between the FV3-challeneged cells and the tissues isolated from infected animals suggest that the additional IFN-expressing populations are rapidly (within 6 h) recruited to the infection sites to mediate the IFN responses. The gene discussed is IFNL4; the disease is infection.