Trace metal modification of immunocompetence: I. Effect of trace metals in the cultures on in vitro transformation of B lymphocytes

Lymphocytes obtained from the spleen of Balb/C mice have been subjected to transformation by LPS in the presence of varying concentrations of Pb 2+, Cd 2+, or Cr 3+. Both DNA and protein turnover were followed. It was found that Pb 2+ and Cr 3+ are mitogenic over a broad range of concentrations, while Cd 2+ is slightly mitogenic at very low (10 −6 M) concentration and rapidly becomes inhibitory of both [ 3H]TdR and [ 3H]ALA uptake. Pb 2+ appears to stimulate the action of LPS, while Cr 3+ appears to inhibit. Each of the metals protects the lymphocytes from cell death arising from incubation with LPS. The mechanism of the observed changes is as yet obscure.