US EPA

725540 

Journal Article 

Lifetime exposure to trichloroethylene (TCE) modulates immune function 

Adams, C; Keil, D; Meyers, K; Eudaly, A; Smythe, J; Eudaly, J; Gilkeson, G; Peden-Adams, MM 

2003 

1 

Toxicologist
ISSN: 0731-9193 

DART/TER/3000789 

72 

S-1 

375 

English 

Trichloroethylene (TCE) is an industrial solvent used in the cleaning and degreasing of metal components in various machine industries. Not only is it commonly inhaled during occupational situations, but its widespread use has resulted in groundwater contamination leading to human exposure via drinking water. It has been reported, in murine studies, that TCE can both exacerbate autoimmune disease and suppress immune function. While these studies have addressed effects in adult rodent models, none have explored immunological effects during developmental stages. To determine the immunological effects of TCE in B6C3F1 mice, exposure to TCE in drinking water (1000 ppb or 10,000 ppb) began when pairs were mated (female C57 and male C3H mice) and continued through weaning (21-day-old) or adulthood (56-days-old). The vehicle control group was administered emulphor-treated water. Endpoints assessed included splenic and thymic weights and cellularity, natural killer cell (NK) activity, antibody plaque forming cell (PFC) response, lymphocyte proliferation, and T-cell immunophenotypes. At 21 days of age, alterations were evident. Body weight and length were significantly decreased by the 10,000 ppb treatment. NK cell activity and T- and B-cell proliferation were not altered. IgM antibody responses to sRBC challenge were suppressed in both male and female pups by 10,000 ppb TCE and by 1000 ppb TCE in the male pups only. Additionally, there was a distinct decrease in splenic CD4+CD8- T-cells resulting in a concomitant decrease in the CD4+:CD8+ ratio. At 56 days of age, the most striking effect was noted with increased NK cell activity in both treatment groups. Currently studies are being conducted to verify the PFC response and T-cell immunophenotypes in the adult mice. These data suggest that lifetime exposure to TCE modulates both innate and adaptive immune responses and this should be considered when assessing health risks to TCE. 

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