| Neutrophil Function after Exposure to Polychlorinated Biphenyls in vitro Patricia E. Ganey,1,2,3 Jay E. Sirois,1 Michael
Denison,3,4 J. Paul Robinson,5 and Robert A. Roth1,3
1Department of Pharmacology and Toxicology, 2Department
of Medicine, 3Institute for Environmental Toxicology, and 4Department
of Biochemistry, Michigan State University, East Lansing, MI 48824 USA;
5Purdue University Cytometry Laboratories and Department of Veterinary
Physiology and Pharmacology, Purdue University, West Lafayette, IN 47906
USA Abstract
Polychlorinated biphenyls (PCBs) are known to be immunotoxic, yet the effects on neutrophil (PMN) function are not well characterized. We incubated PMNs isolated from rat peritoneum with a mixture of PCB congeners, Aroclor 1242, in the absence or presence of either phorbol myristate acetate (PMA) to stimulate generation of superoxide anion (O2-) or N-formyl-methionyl-leucyl-phenylalanine (fMLP) to induce degranulation (measured as release of ß-glucuronidase) . Aroclor 1242 alone stimulated O2- production at a concentration of 10 µg/ml. Significant cytotoxicity was not observed under these conditions. This concentration of Aroclor 1242 also increased O2- generation in PMNs activated with 20 ng PMA/ml. In the presence of a concentration of PMA (2 ng/ml) that by itself did not stimulate production of O2-, 1 µg Aroclor 1242/ml caused significant generation of O2-, indicating synergy between Aroclor 1242 and PMA. Aroclor 1242 caused release of ß-glucuronidase from quiescent PMNs ; however, in PMNs stimulated with fMLP to undergo degranulation, Aroclor 1242 inhibited release of ß-glucuronidase. The effects of two PCB congeners, one that binds to the Ah receptor (3,3´,4,4´-tetrachlorobiphenyl) and one that has little affinity for this receptor (2,2´,4,4´-tetrachlorobiphenyl) were examined. 3,3´,4,4´-Tetrachlorobiphenyl had no effect on PMN function in vitro, whereas 2,2´,4,4´-tetrachlorobiphenyl had effects similar to those observed with Aroclor 1242. These results indicate that PCBs affect PMN function in vitro in a complex manner, stimulating or inhibiting function under different conditions. These effects are apparently not mediated through the Ah receptor. Key words: Ah receptor, degranulation, neutrophils, polychlorinated biphenyls, superoxide anion. Environ Health Perspect 101:430-434 (1993)
Address correspondence to P.E. Ganey, Department of Pharmacology and Toxicology, Life Sciences Building, Michigan State University, East Lansing, MI 48824 USA. This work was supported by grant ES04911 from NIEHS. R.A.R. was supported in part by a Burroughs Wellcome Toxicology Scholar Award. We thank Maria Colligan, Dianne Schwartz, and Eric Shobe for excellent technical assistance. Received 2 February 1993 ; acccepted 21 June 1993.
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