ABSTRACT
Acknowledgments .........................................................................................................................281
References .....................................................................................................................................281
Biological monitoring is the assessment of exposure to an agent through the measurement of
biomarker(s) that result from contact with the agent(s). Examples are zinc protoporphyrin in
blood, levels of which increase with lead exposure because lead inhibits the biosynthesis of
heme; protein and DNA adducts of aromatic amines in blood that can both reflect the intensity
of exposure and be correlated with the biologically effective dose; antibodies (Abs) produced
against low-molecular-weight molecules-some chemicals, although not immunogenic in their
own right because of small size and other limitations, may bind to constitutive polymers (such
as host proteins) and become immunogenic, causing the production of specific antibody (Ab).
Alternatively, such exposures may lead to the production of new antigenic determinants through
non-adduct-forming reactions between the agent and selected protein-carrier molecules. Abs can be
made to these modified proteins or to the parent hapten-conjugate. In both cases, the Abs may
remain in the human system much longer than the toxicant that initiated their development.