Identification of human autoantibodies to the transcriptional repressor ZF5

ZF5 was originally cloned as a transcriptional repressor on the mouse c-myc promoter. It contains the Kruppel-type zinc fingers and a conserved POZ do main, which is found in a growing number of zinc finger proteins and mediat e protein-protein interactions. Autoantibodies against transcription factor s are sometimes found in sera from patients with high levels of anti-nuclea r antibody (ANA). Using Western blotting with ZF5 and sera of autoimmune di sease, we detected one serum, named M6 serum, which contains the antibody a gainst a transcriptional repressor ZF5. The confirmed epitope was specific to ZF5 and was not reactive to the other analogous factors: BCL-6, ZID, and Sp1. This epitope also has a molecular mimicry of the viral proteins. From these results, we predict that viral protein which mimics host ZF5 antigen triggers self-reactive T cell clones and induces the autoantibody in M6 se rum after the destruction of host tissues. (C) 2000 Academic Press.