PRODUCTION OF A NOVEL RECOMBINANT CELL-LINE FOR USE AS A BIOASSAY SYSTEM FOR DETECTION OF 2,3,7,8-TETRACHLORODIBENZO-P-DIOXIN-LIKE CHEMICALS

Exposure to specific halogenated aromatic hydrocarbons (HAHs), such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), can produce a wide variet y of species-and tissue-specific toxic and biological effects. The pre sence of HAHs in environmental samples as complex mixtures has made it difficult to predict the biological and toxic potency of these chemic als. We have used aspects of the molecular mechanism of action of thes e chemicals to develop a species-specific bioassay system for detectio n of bioactive HAHs in complex mixtures. Here we describe construction and utilization of a recombinant expression vector that responds to t hese HAHs with the induction of an easily measurable gene product, hea t-stable human placental alkaline phosphatase (PAP). This vector conta ins the PAP gene under TCDD-inducible control of four dioxin-responsiv e DNA enhancer elements. HAH-inducible expression of PAP from the reco mbinant vector occurs in a dose-and Ah-receptor-(AhR-) dependent manne r. Stable transfection of this vector into mouse hepatoma cells has pr oduced a novel cell line in which AhR-dependent induction of gene expr ession can easily be measured. This transfected cell line can readily be used for detection and relative quantitation of AhR agonist in comp lex mixtures of environmental and biological samples and for identific ation and characterization of novel AhR agonists.