The complementary double-stranded (ds) oligonucleotides (oligos) from the TNFα, IL-8, IFNγ and IL-6 promoters were synthesised from single stranded (ss) oligos (illustrated in Table 1), (TIB Molbiol, Berlin, Germany) and 32P-labeled with 5'γ-P-ATP (3,000 Ci/mmol, Amersham, Braunschweig, Germany) using the Ready-To-Go-Polynucleotide-Kinase Kit (PNK Kit, Pharmacia LKB, Freiburg, Germany) according to the manufacturer's instructions. To test the binding specificity of the oligos, mutated oligos were used as an additional control. Mutations in the P2 site of the IFNγ promoter [29] and in the κ consensus sequence of the TNFα promoter [55] have been reported to interfere with sequences, which seem to be crucial for the binding of NFAT and NFκB proteins, respectively. Afterwards, the ds oligos were purified via gel filtration using Probe Quant G-50 Micro Columns (Pharmacia) according to the manufacturer's instructions.