Further Characterization of Monoclonal Antibody Indicates Specificity for (6–4)‐dipyrimidine Photoproducts

Monoclonal antibody aUVssDNA‐1 is produced by hybridoma cell line 25JF.C3B6 originally selected from cell fusions using spleen cells from mice immunized with UV‐irradiated polydeoxynucleotides (Strickland and Boyle, Photochem. Photobiol. 34 , 595–601, 1981). Original and subsequent studies of the binding characteristics of aUVssDNA‐1 indicated that it was specific for cyclobuta‐dithymidine photoproducts. Those investigations examined action spectrum, short‐wavelength photo‐reversal, nucleotide sequence effects, and photoreactivation using E. coli photolyase and incandescent tight. However, the more recent studies reported here examined acetophenone‐UV‐B photosensitization, UV‐B photoisomerization, and photoreactivation using cloned E. coli photolyase and filtered incandescent light. The results indicate that aUVssDNA‐1 recognizes photoproducts with characteristics of (6–4)‐dipyrimidines. Thus, previous studies in which relatively rapid repair of cyclobuta‐dithymidine photoproducts was inferred using this antibody, require re‐interpretation in light of these new findings.