NATIVE DNA FRAGMENTS PHOTOCROSSLINKED TO PSORALEN BINDS TO ANTI-B ANDANTI-Z DNA ANTIBODIES

Calf thymus DNA fragments of varying size (100-600 bp) were covalently linked to psoralen in the presence of 365 nm UV light. The crosslinke d species were separated from the monoadducts by hydroxyapatite column chromatography. The DNA-psoralen crosslink showed binding with natura lly occurring anti-DNA autoantibodies. This was substantiated by the r ecognition of affinity purified IgG by DNA-psoralen crosslinks of vary ing DNA size. The photo-crosslinks exhibited considerable recognition of both monoclonal and polyclonal anti-Z-DNA antibodies in inhibition ELISA and band shift assay.