Effect of dietary chronic cadmium exposure on cell-mediated immune response in rhesus monkeys (Macaca mulatta): role of calcium deficiency.

The role of Ca deficiency on the immunomodulatory effects of chronic Cd exposure for a period of 10 weeks in male Rhesus monkeys were assessed by the blastogenic capacity of peripheral blood lymphocytes (PBL) in response to T-cell mitogens, phytohemagglutinin (PHA), and concanavalin A (Con A). Calcium deficiency significantly decreased the blastogenic response to PHA (P less than 0.01) and Con A (P less than 0.05). Although Cd exposure in normal monkeys significantly increased the blastogenic response to Con A (P less than 0.05), Cd exposure in Ca-deficient monkeys produced a further significant decrease in the blastogenic response to Con A (P less than 0.001). Total and ionic Ca were also significantly decreased in plasma of Ca deficient monkeys exposed to Cd. It is possible that these two observations may be related to each other. Thus, it is important to assess the nutritional status of the host while evaluating the immunotoxicological effects of an environmental pollutant.