Zinc modulates mitogenic responses of human lymphocytes by affecting structures influenced by cytochalasin B

We have previously reported that zinc affects the mitogenic process in an age-dependent fashion when added to lectin-stimulated lymphocytes. The present studies demonstrate an additional selective effect of zinc when added to Con A-activated lymphocytes plus pharmacologic agents known to affect the cytoskeleton or the permeability of the plasma membrane. Specifically, addition of zinc did not modulate the dose-dependent activities of Ca²⁺ ionophore A23187, nigericin, or colchicine demonstrating that the immunologic effects of zinc do not involve modification of Ca²⁺ or K⁺ fluxes, or microtubule formation. By contrast, a consistent and reproducible shift in the cytochalasin B dose-response curve of lymphocytes stimulated by Con A was observed when zinc was added. These data indicate that the effect of zinc on immune functions may be operating through cytochalasin B-sensitive subcellular structures, most likely microfilaments.