Early effects of lead on bone marrow cell responsiveness in mice challenged with Listeria monocytogenes.

Listeria monocytogenes challenge of lead-treated mice results in increased mortality. Since macrophage development constitutes the initial phase of the immune response to L. monocytogenes, bone marrow and spleens from Pb-treated mice that were infected with L. monocytogenes were analyzed for their ability to form colonies when exposed to the macrophage growth factor CSF-1. Serum colony-stimulating activity also was evaluated. Data obtained indicate the Pb exposure results in decreased responsiveness of bone marrow and spleen cells to CSF-1 while colony-stimulating activity in serum rises. This lack of bone marrow-derived macrophage development may contribute to the increased mortality observed with L. monocytogenes challenged. Pb-treated mice.