In vitro effects of saccharin on cell-mediated host defence mechanisms

In vitro exposure to saccharin (0.1-2 mg/ml) did not affect the tumoricidal activity of macrophages and natural killer (NK) cells from mice and rats. In contrast saccharin at doses of 0.5-2 mg/ml significantly and consistently depressed the blastogenic response of rat lymph node cells to phytohemagglutinin (PHA). Similarly mouse splenocytes showed impaired responsiveness to PHA and bacterial lipopolysaccharides n the presence of 2 mg/ml saccharin. Compared with murine lymphoid cells, human peripheral blood lymphocytes were relatively resistant to the immunodepressive activity of saccharin, a low but significant, depression (21%) of the response to PHA being observed only at the highest concentration (2 mg/ml) in 1 of 3 normal healthy donors tested.