A synthetic hapten for induction of thymine‐dimer‐specific antibodies

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Abstract
High specificity and sensitivity of thymine cyclobutane dimer (thy[]thy) detection was obtained by a radioimmunoassay. Attempts to raise thy[]thy-monospecific antibodies with antigens produced according to conventional methods were unsuccessful. Thy[]thy-specific antibodies could only be raised by using a new strategy to bind thy[]thy to protein: thymine was activated by trimethylsilylation and alkylated at N1 yielding N1-thyminebutanoic acid which was dimerized by UV treatment. The resulting derivative of thymine cyclobutane dimer was coupled to bovine serum albumin by the active-ester method. The new strategy appears to be generally applicable for binding haptens, such as DNA bases, photoproducts, etc. to proteins via a derivative containing a carboxyl group. Immunization of rabbits with thy[]thy-bovine-serum-albumin conjugate prepared by the new method resulted in a highly specific antiserum which allows detection of thy[]thy down to 0.06 pmol (15pg). The thy[]-specific radioimmunoassay was applied to measure thy[]thy formed in human fibroblasts which were exposed to sunlight at altitudes of 600 m or 2300 m. The amounts of thy[]thy formed in an hour corresponded to doses of 14 j m-2 and 24 J m-2, respectively, of an UV light lamp emitting predominantly 245-nm light.