Molecular distribution of cytoplasmic zinc in phytohemagglutinin-stimulated and unstimulated human lymphocytes

Human peripheral blood lymphocytes were incubated with [⁶⁵Zn] zinc transferrin and with and without phytohemagglutinin for 1, 2, 4, 10, 24, 48, 72, and 96h. Gel filtration of cytoplasmic fractions obtained from these lymphocytes was then performed to determine the molecular distribution of incorporated zinc as a function of time in culture. The data obtained indicated that: (1) transferrin-bound zinc incorporated by human lymphocytes is associated with a variety of soluble molecules whose molecular weights range from less than 5,000 to greater than 70,000 daltons; (2) there is a time-dependent change in the distribution of cytoplasmic zinc for both phytohemagglutinin-stimulated and unstimulated lymphocytes; and (3) for all times studied, there is a difference in the elution profiles obtained for phytohemagglutinin-stimulated and unstimulated lymphocytes. Furthermore, lymphocytes from a donor with untreated hairy cell leukemia exhibited a totally different pattern of cytoplasmic zinc distribution than did lymphocytes from apparently healthy donors.