title: Subclinical effects of groundwater contaminants. III. Effects of repeated oral exposure to combinations of benzene and toluene on immunologic responses in mice.
abstract: Toxicity of environmental pollutants may be expressed as combined effects of a chemicals. Benzene, a proven hematotoxic agent, frequently occurs with toluene in cocontaminated groundwater. Groups of CD-1 male mice were exposed continuously for 4 weeks to benzene (166 mg/l), toluene (80 and 325 mg/l), and combinations of benzene (166 mg/l) + toluene (80 mg/l or 325 mg/l) in drinking water. Benzene-induced anemia was alleviated by simultaneous toluene treatment. Leukopenia and lymphopenia were observed in the case of benzene only and benzene + toluene (80 mg/l)-treated mice. The cytopenia, however, was less severe in the benzene + toluene (325 mg/l)-treated group. Immunotoxicity induced by benzene treatment alone was characterized by involution of thymic mass and suppressions of both B- and T-cell mitogeneses, mixed lymphocyte culture response to alloantigens, the tumor lytic ability of cytotoxic T-lymphocytes as determined by 51Cr-release assay, and antibody production response to T-dependent antigen (sheep red blood cells). IL-2 secretion by Con A-stimulated mouse T-cells was decreased in the benzene-treated group. Toluene (325 mg/l) completely inhibited these adverse effects when it was coadministered with benzene, while the low dose of toluene (80 mg/l) did not protect against benzene-induced depressions of immune functions. Toluene administered alone at levels up to 325 mg/l showed no obvious immunotoxic effects. Results of this study demonstrated that toluene, in sufficient amounts, has an antagonistic effect on benzene immunotoxicity.
authors: Department of Biology, Utah State University, Logan 84322.
authors: G C
authors: GC
authors: Hsieh
authors: R D
authors: RD
authors: Parker
authors: R P
authors: RP
authors: Sharma
authors: B J
authors: BJ
authors: Hughes
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000917:Antibody Formation / Q000187:drug effects; D001554:Benzene / Q000008:administration & dosage / Q000633:toxicity; D002849:Chromatography, Gas; D004781:Environmental Exposure; D004906:Erythrocyte Count / Q000187:drug effects; D007107:Immune System / Q000187:drug effects*; D007111:Immunity, Cellular / Q000187:drug effects; D007376:Interleukin-2 / Q000096:biosynthesis; D007958:Leukocyte Count / Q000187:drug effects; D007959:Lymphocyte Culture Test, Mixed; D008214:Lymphocytes / Q000187:drug effects; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D008934:Mitogens / Q000494:pharmacology; D008938:Mitosis / Q000187:drug effects; D014050:Toluene / Q000008:administration & dosage / Q000633:toxicity; D014873:Water Pollutants / Q000633:toxicity*; D014874:Water Pollutants, Chemical / Q000008:administration & dosage / Q000633:toxicity*
chemical_list: D007376:Interleukin-2; D008934:Mitogens; D014873:Water Pollutants; D014874:Water Pollutants, Chemical; D014050:Toluene; D001554:Benzene