EFFECTS OF CHLORINATED SOLVENTS ON THE NATURAL LYMPHOCYTOTOXIC ACTIVITIES OF HUMAN LIVER IMMUNE CELLS

Inhibition of the natural immune system may be involved in the liver c ancer caused by some non-genotoxic chemicals when they are administere d at high doses to certain strains of animals. Previous studies have s hown that some chlorinated solvents inhibit liver natural immune funct ion in rodents. In this preliminary study, the effects of in vitro exp osure to three commonly used chlorinated solvents were determined on t hree tumoricidal activities expressed by isolated human liver immune c ells-natural killer (NK), natural cytotoxic (NC) and natural P815 kill er (NPK) (Wright and Stacey, 1991) cell activities. The NK, NC and NPK cell activities of immune cells isolated from three human livers were 115, 45 and 53 lytic units (LU20%/10(6) effector cells), respectively . In vitro exposure to trichloroethylene (TRI) inhibited all three nat ural immune activities, and the ranking of sensitivity was NPK > NC > NK. Tetrachloroethylene (TET) inhibited NC and NPK cell activities, bu t had little effect on NK cell activity. 1,1,1-Trichloroethane (TCE) h ad little or no effect on the three tumoricidal activities examined. O verall, these data show clear similarities to the results obtained in vitro using cells from experimental animals.