In vitro effects of PCDDs/Fs on NK-like cell activity of Eisenia andrei earthworms

Abstract

In this study, we assessed<em> in vitro</em> the effects of PCDD/Fs on the NK-like cell activity in<em> Eisenia andrei</em> earthworms using flow cytometry for analysis. NK-like coelomocytes isolated from <em>E. andrei</em> and used as effectors were exposed to various concentrations of PCDDs/Fs mixture, C1 (6.25x10-3 ng 2378- TCDD/mL), C2 (12.5x10-3 ng 2378-TCDD/mL) and C3 (25x10-3 ng 2378-TCDD/mL), before adding them to human tumoral cells (K562) used as targets. We evaluated the percentage of targets lysed by Nk-like cells. The results showed a significant stimulation of the NKlike activity at C3 when PCDD/Fs were not removed from effectors before contact with targets, while no effects were noted when the effectors were washed (PCDD/Fs removed) or fixed. Assessment of the viability of the targets (K562), exposed alone and separately from effectors, to the three concentrations of PCDD/Fs, C1, C2 and C3, showed that all these concentrations were cytotoxic for K562. Results suggest that PCDD/Fs concentrations tested in this assay may be considered too low to induce suppressive effects on the immune function such as the NK-like activity in <em>E. andrei</em> earthworms.