Silver and fullerene nanoparticles' effect on interleukin-2-dependent proliferation of CD4 (+) T cells

Immunotoxicity studies of nanoparticles on T cells addressed their effects on activation by T antigen receptor, but have neglected the regulation of proliferation by IL-2. In this study, the IL-2-dependent T lymphoblastoid WE17/10 cell line was used to compare silver (Ag-NPs) and fullerene (C60-NPs) nanoparticles' toxicity and evaluate whether these NPs could interfere with IL-2-dependent proliferation. Results have shown that Ag-NPs are more toxic, as they reduced cell viability at the highest concentration tested (100 μg/ml), while C60-NPs have shown good biocompatibility. Characterization of NP suspensions by dynamic light scattering measured large aggregates for C60-NPs, whereas Ag-NPs were relatively stable and well dispersed. This translated into a much larger uptake of Ag-NPs compared to C60-NPs, as measured by flow cytometry. Proliferation measurements by CFSE following 72 h incubation have shown that Ag-NPs decrease cell proliferation and C60-NPs slightly increase proliferation. CD25 expression was unchanged following exposure to C60-NPs, but was significantly increased by Ag-NPs' presence for short and long-term incubations. Analyses of three key signaling proteins activated by IL-2 receptor (Stat5, JNK and ERK1/2) by western immunoblotting have shown no effects from either NPs on Stat5 and JNK phosphorylation. ERK1/2 was slightly activated following a short exposure to Ag-NPs, while C60-NPs had no effect. Our results show that C60-NPs have good biocompatibility and do not interfere with IL-2-dependent proliferation. A deeper investigation would be needed for the case of Ag-NPs, since the mechanism of their action is still unclear.