P117 displayed impaired IFNα response. (A) PBLs of ENU-mutagenized mice were stimulated without or with IFNα 1000 U/ml for 21 h followed by staining with antibodies to MHC class I and ICAM-1 and analyzed by flow cytometry. (B) PBLs of ENU-mutagenized mice were stimulated with IFNγ 500 ng/ml or IFNα 1000 U/ml for 3 h followed by preparation of mRNA for RT-QPCR using primers to IP-10 (IFNγ and IFNα), SOCS1 (IFNγ), OAS (IFNα) and PKR (IFNα). Stimulation index was calculated as described in the Materials and Methods. Relative mRNA was shown by normalizing the values of specific genes to that of β-actin. Arrow heads are P117.