Detection of Carcinogen–Macromolecular Adducts in Humans

Antisera specific for carcinogen-DNA adducts and carcinogen-modified DNA: applications for detection of xenobiotics in biological samples

The development of immunoassays and immunoaffinity chromatography methods for determination of carcinogen-DNA adducts and carcinogen-modified DNA samples rests upon eliciting and characterizing polyclonal and monoclonal antisera against these haptens. The use of such antisera has widespread application in investigating chronic carcinogen administration in animal models and in monitoring human tissues for evidence of carcinogen exposure. Radioimmunoassays and enzyme-linked immunosorbent assays developed with carcinogen-DNA adduct antisera are exceedingly sensitive, measuring 1 adduct in 10(8) nucleotides. Not only can DNA damage be quantified directly by immunoassay, but the antisera have also been used to isolate DNA adducts of a particular chemical class by immunoaffinity chromatography before application of more chemically-specific end-points. Both of these methodological approaches have made seminal contributions to the newly-emerging field of molecular epidemiology. This chapter will focus on methods for preparing immunogens, the establishment of immunoassays, characterization of antisera and specific problems encountered with biological samples in addition, the use of immunoaffinity chromatography for preparative concentration of DNA adducts of a particular class will be included.

Decision model for biomarkers of exposure

The quantitation of exposure is one of the most critical elements of the risk assessment process. Contemporary risk assessment models rely on monitoring the target chemical in various environmental media and incorporate a variety of assumptions to estimate this. Recently, biomarkers have been advanced to improve estimates of the delivered dose of a given chemical or mixture of chemicals. A biomarker of exposure may be defined as an indicator of exposure to an environmental pollutant within the exposed organism, which becomes manifest before any adverse effects are evident. Measurement of such a biomarker within a biological system may potentially be used to identify and quantitate directly exposure to hazardous substances. This paper describes a decision model for the selection, evaluation, and validation of a biomarker of exposure.