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Background and objective: Paraquat is one of the most widely used global herbicides for weed control. Recently, paraquat has been reported to have immune toxic effects in animal models, while effects on human T cell function remain undetermined. To resolve these issues, the effects of paraquat on IFN-g production by human T cells in vitro were evaluated.
Methods: Peripheral blood mononuclear cells were co-cultured with various concentrations of paraquat dichloride or phytohemagglutinin (PHA). Cell viability was determined by trypan blue exclusion and relative metabolic activity was assayed by MTT method. IFN-g production was measured after co-culture with phytohemagglutinin by ELISA.
Results: Paraquat at 100 µg/mL did not affect cell viability, whereas 300 µg/mL paraquat significantly reduced the percentage of viable cells compared with the control (p< 0.05). Addition of 100 and 300 µg/mL of paraquat significantly increased the percentage of IFN-g production inhibition compared with the control (p< 0.05). Moreover, inhibition of IFN-g production by paraquat was observed after 24 h co-culture and showed a robust effect in all individuals after 48 h co-culture.
Conclusion: Data indicated that paraquat at the concentration of 100 and 300 µg/mL had an inhibitory effect on IFN-g production by T cells. Thus, direct contact with paraquat or paraquat contaminated environments and agricultural products increased risk of diseases caused by T cell dysfunction.
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