THE TARGET-CELLS OF INJECTED TYPE-I INTERFERONS IN MOUSE-LIVER

Type I interferons (IFNs) have been used for the treatment of viral he patitis, but it is unclear which cells in the liver are affected by in jected IFN, The effects of IFN have been studied by the production of 2',5'-oligoadenylate synthetase (2'5'OAS), an IFN-inducible enzyme, He re, we studied the distribution of 2'5'OAS in mouse liver after inject ion of natural mouse IFN-alpha/beta by Western blotting and immunohist ochemistry using a monoclonal antibody specific to mouse 42-kDa 2'5'OA S, Injection of IFN-alpha/beta increased the levels of liver 2'5'OAS a nd enhanced the intensities of immunohistochemical staining for this e nzyme in both hepatocytes and Kupffer cells, In IFN-untreated normal m ice, hepatocytes were lightly stained, but some of the Kupffer cells s howed rather strong staining, The 2'5'OAS-positive Kupffer cells compr ised similar to 60% of those in normal liver, whereas this increased t o similar to 90% following IFN-alpha/beta injection, Thus, hepatocytes and Kupffer cells were the targets of injected IFN.