Fig. 8. Mechanisms involved in NP-induced immunomodulation. The stimulation/suppression of the immune system depends on the nature of the NPs and results in different outcomes. NPs, nanoparticles; NF-κB, nuclear factor kappa B; TLR pathway: toll-like receptor pathway; APC, antigen-presenting cell; DCs, dendritic cells; MCs, mast cells; GM-CSF, granulocyte-macrophage colony-stimulating factor; Th0, type 0 T-helper lymphocyte; Th1, type 1 T-helper lymphocyte; Th2, type 2 T-helper lymphocyte; solid line with arrow, activate/release/induce; solid line with vertical dashes at ends, inhibit; dotted line, possible influence; broken line, polarization/differentiation. Reproduced with permission from ref. 234, © 2014, Hindawi Publishing Corporation.