Ibs Klaus-Helge, Rink Lothar
Institute of Immunology, University Hospital, Technical University of Aachen, D-52074 Aachen, Germany.
J Nutr. 2003 May;133(5 Suppl 1):1452S-6S. doi: 10.1093/jn/133.5.1452S.
Zinc is known to be essential for all highly proliferating cells in the human body, especially the immune system. A variety of in vivo and in vitro effects of zinc on immune cells mainly depend on the zinc concentration. All kinds of immune cells show decreased function after zinc depletion. In monocytes, all functions are impaired, whereas in natural killer cells, cytotoxicity is decreased, and in neutrophil granulocytes, phagocytosis is reduced. The normal functions of T cells are impaired, but autoreactivity and alloreactivity are increased. B cells undergo apoptosis. Impaired immune functions due to zinc deficiency are shown to be reversed by an adequate zinc supplementation, which must be adapted to the actual requirements of the patient. High dosages of zinc evoke negative effects on immune cells and show alterations that are similar to those observed with zinc deficiency. Furthermore, when peripheral blood mononuclear cells are incubated with zinc in vitro, the release of cytokines such as interleukins (IL)-1 and -6, tumor necrosis factor-alpha, soluble IL-2R and interferon-gamma is induced. In a concentration of 100 micro mol/L, zinc suppresses natural killer cell killing and T-cell functions whereas monocytes are activated directly, and in a concentration of 500 micro mol/L, zinc evokes a direct chemotactic activation of neutrophil granulocytes. All of these effects are discussed in this short overview.
锌被认为对人体所有高度增殖的细胞至关重要，尤其是免疫系统。锌对免疫细胞的多种体内和体外作用主要取决于锌的浓度。锌缺乏后，各类免疫细胞的功能都会下降。在单核细胞中，所有功能都会受损；而在自然杀伤细胞中，细胞毒性会降低；在中性粒细胞中，吞噬作用会减弱。T细胞的正常功能受损，但自身反应性和同种异体反应性会增强。B细胞会发生凋亡。锌缺乏导致的免疫功能受损可通过适当补充锌来逆转，补充量必须根据患者的实际需求进行调整。高剂量的锌会对免疫细胞产生负面影响，并表现出与锌缺乏时类似的变化。此外，当外周血单核细胞在体外与锌孵育时，会诱导白细胞介素（IL）-1和-6、肿瘤坏死因子-α、可溶性IL-2受体和干扰素-γ等细胞因子的释放。在100微摩尔/升的浓度下，锌会抑制自然杀伤细胞的杀伤作用和T细胞功能，而单核细胞会被直接激活；在500微摩尔/升的浓度下，锌会引起中性粒细胞的直接趋化激活。本简短综述对所有这些作用进行了讨论。
