Pentachlorophenol and dichlorodiphenyltrichloroethane alter secretion of interleukin 1-β (IL-β) from human immune cells

Pentachlorophenol (PCP) and Dichlorodiphenyltrichloroethane (DDT) are environmental contaminants found in human blood. PCP, a chlorinated aromatic compound, has been used in fungicides, insecticides, herbicides, and antifouling paint. In the United States, it has mostly been used as a preservative to treat wooden utility poles and to preserve the wood used in the production of log homes. Although 4, 4′-Dichlorodiphenyltrichloroethane (4, 4′-DDT), has been banned in the U.S., it is still used in other countries as a pesticide to kill insects. Cancers of the blood (lymphoma and myeloma) and kidney have been associated with exposure to these contaminants. Previous studies in our lab show that PCP and DDT inhibit the lytic function of highly purified human natural killer (NK) lymphocytes and decrease the expression levels of several surface proteins on NK cells. Interleukin 1-βeta (IL-1β) is a cytokine produced by lymphocytes and monocytes. It is involved in stimulating cell proliferation, tissue repair, and present during the inflammatory response to injury. An increase or decrease in the level of IL-1β may lead to immune dysfunction and increased potential for tumor development and invasiveness. The objective of this study was to examine if exposure of human immune cells to different concentrations of PCP and DDT alters the secretion of IL-1β. Immune cells included peripheral blood mononuclear cells (PBMCS), monocyte-depleted (MD) cells, T-cells, natural killer (NK) cells, and PBMCS/MD-PBMCS cells. Cells were exposed to concentrations of PCP ranging from 5 µM to .05 µM and DDT concentrations of 2.5µM to .025µM for 24h, 48h and 6 days. Secreted IL-1β levels were measured using ELISA (enzyme-linked immunosorbent assay). Results showed that PCP and DDT induced alterations in IL-1β secretion by human immune cells. There were increases in IL-1β secretion from immune cells exposed to different concentrations of PCP and DDT. The exact concentrations of PCP and DDT that increased IL-1β secretion varied by donor. Alterations in IL-1β secretion of human immune cells following exposure to PCP and DDT may potentially cause dysregulation and facilitate cancer metastasis