Zinc and immunity: implications for growth, survival and function of lymphoid cells

Constant dietary intake of the group IIb metal Zn is essential for growth and development, as well as for the functional integrity of most, if not all, of the tissue/organ systems in the body. Included amongst these, and arguably the most Zn-dependent, is the immune system; not only does severe Zn deficiency have rapid and profound detrimental effects on absolute numbers and functional states of the lymphoid cells but the immune system is compromised even in mild Zn deficiency, when many other tissues of the body are relatively unaffected. Any consideration of the role of Zn in normal cellular physiology must take into account this extreme sensitivity of the immune cells to Zn depletion. In this review, I will commence with the more descriptive studies of the influence of Zn nutrition on the development and function of the immune system in vivoand in vitro. I will then focus on recent studies concerning the role of Zn in growth, survival, signal transduction and other metabolic events in lymphoid...