Conventional RT-PCR, real-time RT-PCR, analysis of IFN-áâ subtypes and Chromatin Immunoprecipitation Total RNA was isolated from organs and cells with guanidinium-thiocyanate-phenol-chloroform extraction or with TRI reagent (Sigma). To exclude DNA contamination, RNA samples were treated with RNase free DNase I (Fermentas). cDNA was prepared using Expand reverse transcriptase (Roche) and oligo-dT. Conventional RT-PCRs were performed with primers as follows. [102, 103] , detecting all IFN-a mRNAs. To determine the levels of different IFN-ab subtypes the HT7900 quantitative PCR system (Applied Biosystems) was used. cDNAs were measured in duplicates or triplicates using the following genespecific assays (TaqMan Gene Expression Assays, Applied Biosystems):