Immunomodulation following zinc supplementation during chelation of lead in male rats.

Influence of zinc supplementation (30 and 45 mg kg-1, orally once for 5 days) during chelation of lead (0.3 mmol kg-1, chelating agent, i.p., once for 5 days) on some selected variables of the immune system was investigated in male rats. Treatment with CaNa2EDTA either alone or in combination with zinc (30 mg kg-1) produced a significant recovery in lead induced alteration in primary antibody forming cells to T-dependent antigen and the delayed-type hypersensitivity response to bovine albumin. However, biologically significant recovery was observed only with zinc at a dose of 45 mg kg-1. It is assumed that zinc depletion during lead exposure and chelation treatment lead to harmful effects on cellular proliferation by inhibiting DNA synthesis and various enzymes during mitosis. The zinc supplementation fulfills this requirement during proliferation and clonal expansion of immunocompetent cells augmenting the immune system.