Commercial gold nanocolloid inhibits synthesis of IL-2 and proliferation of porcine T lymphocytes

•Commercial gold nanocolloid is not cytotoxic to porcine peripheral blood mononuclear cells.•Investigated nanocolloid does not affect resting porcine T cells.•High nanocolloid concentration inhibits ConA-stimulated proliferation of T cells by down-regulation of the IL-2 synthesis.•The most affected by nanogold subpopulation were double negative CD4−CD8α− T cells.

Recent intensive development of nanotechnology has broadened the use of noble metal nanocolloids in alternative medicine. Meanwhile, silver and copper nanoparticles are tested as potential feed additives in pig farming. Experiments on rodents prove that metal nanocolloids easily interact with macrophages and lymphocytes, although the specific nature of pigs' immune system means that rodent tests may not reflect fully the responsiveness of porcine T cells. Our purpose was to demonstrate the effect of a commercial gold nanocolloid on percentages and proliferation of T lymphocyte subpopulations and on IL-2 and IL-10 synthesis in porcine peripheral blood mononuclear cells tested in vitro. The nanocolloid was not cytotoxic to porcine leukocytes, nor did it affect resting T cells. However, high nanogold concentrations inhibited proliferation of mitogen-stimulated CD4+, CD4+CD8α+ and CD4−CD8α− T cells by down-regulation of the IL-2 synthesis and increased the percentage of CD4−CD8α− double negative T cells, probably by depressing their ability to express a CD8α marker after activation. The observations implicate potential immunosuppressive activity of nanogold and strong influence of nanoparticles on CD4−CD8α− T cells, the most abundant subpopulation in young animals, suggests its particular effect on a developing immune system.