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It is known that exposure to As(+3) via drinking water causes a disruption of the immune system and significantly compromises the immune response to infection. The purpose of these studies was to assess the effects of As(+3) on bone marrow progenitor cell colony formation and the humoral immune response to a T-dependent antigen response (TDAR) in vivo. In a 30 day drinking water study, mice were exposed to 19, 75, or 300 ppb As(+3). There was a decrease in bone marrow cell recovery, but not spleen cell recovery at 300 ppb As(+3). In the bone marrow, As(+3) altered neither the expression of CD34+ and CD38+ cells, markers of early hematopoietic stem cells, nor CD45-/CD105+, markers of mesenchymal stem cells. Spleen cell surface marker CD45 expression on B cells (CD19+), T cells (CD3+), T helper cells (CD4+) and cytotoxic T cells (CD8+), natural killer (NK+), and macrophages (Mac 1+) were not altered by the 30 day in vivo As(+3) exposure. Functional assays of CFU-B colony formation showed significant selective suppression (p |
