The effect of zinc on normal and neoplastic T-lymphocyte proliferation.

After 24-72 h of PHA-stimulation, T-cells expressed the transferrin receptor. This receptor facilitates zinc uptake. Zinc transferrin stimulated DNA synthesis in pre-activated or activated, but not in resting T-cells. The regulatory nuclear protein matrix fraction increased from 5 to 40% of the total nuclear protein material in lymphocytes simultaneously with the initiation of DNA synthesis. In contrast, optimal concentration (0.1-0.4 mM) of zinc salts induced a mitogenic response in transferrin-receptor negative resting, but not in PHA-activated or leukemic T-cells. Higher concentrations were toxic. These findings can explain earlier reports on the effect of zinc on immunocompetence in zinc deficient mice and enteropathic acrodermatitis as well as present findings of a normalization of the T-suppressor-cell number in immunosuppressed patients.