The immunomodulatory effect(s) of lead and cadmium on the cells of immune system in vitro

A number of studies documented that the heavy metals are not only toxic for the organisms but they may modulate immune responses. The immunomodulatory activity was proved in several irt vivo and bl vivo model systems. In the current study, immunomodulatory activities of lead and cadmium are presente d. The viability of both lymphocytes and macrophages was affected by heavy metals in a dose- and time-dependent manner. Tn the case of lead, the depre ssion of N-oxide production closely correlated with increased blast transfo rmation of spleen cells induced by concanavalin A (ConA), On the contrary, cadmium suppressed the production of N-oxides but stimulated significantly the proliferation of spleen cells. The production of cytokines by lymphocyt es and macrophages was dependent on the in vitro model used. Generally, the treatment of macrophages with lead results in disregulation of the product ion of proinflammatory cytokines \tumour necrosis factor alpha (TNF-alpha), interleukin \alpha (IL-1 alpha) and interleukin 6 (IL-6)\ and preferential production of Th1 type of cytokines (IFN-gamma and IL-2), Cadmium seemed t o trigger the Th2 cytokine regulatory pathway \interleukin 4 (IL-4), interl eukin 10 (IL-IO)\. The results suggest the metal-induced changes in immunor egulatory mechanism of host with potentially severe clinical consequences. (C) 2000 Elsevier Science Ltd. AII rights reserved.