The effect of magnetic nanoparticles of Fe(3)O(4) on immune function in normal ICR mice

We investigated the effect of magnetic nanoparticles of Fe(3)O(4) (Fe(3)O(4)-MNPs) on the mice immune system. Imprinting control region (ICR) mice were assigned randomly into four groups and treated with normal saline or low, medium, or high doses of Fe(3)O(4)-MNPs, respectively. After intravenous administration of Fe(3)O(4)-MNPs for 72 hours, the peripheral T cells and the induction of primary immune responses in mice were investigated by flow cytometry and determined using enzyme-linked immunosorbent assay, respectively. The results showed that the ratio of spleen to body weight was not different between the experimental groups and control group (P > 0.05). The lymphocyte transformation rates in the suspension of spleen were higher in low-dose group than those in the control group (P < 0.05), while the proliferation of splenocytes was low in the medium and high groups when compared to the control group (P < 0.05). In peripheral blood, both the proportions of subset CD4(+) and CD8(+) T lymphocytes in the low-dose group were higher than those in the control group, whereas there was no difference in the number of CD4(+) T cells between the medium- and low-dose groups. Interestingly, the Fe(3)O(4)-MNPs enhanced the production of interleukin-2 (IL-2), interferon-γ, and IL-10 but did not affect the production of IL-4 in peripheral blood. It is concluded that Fe(3)O(4)-MNPs could influence immune functions of normal ICR mice in a dose-dependent manner.