Effect of low-level lead exposure on antibody-dependent and natural killer cell-mediated cytotoxicity.

Splenic antibody-dependent, cell-mediated cytotoxicity against chicken red blood cell targets [ADCC (CRBC)] and natural killer cell-mediated cytotoxicity (NKMC) were determined in C57BL/6 mice given 1300 ppm lead acetate (827 ppm lead) in their drinking water for 8 weeks. ADCC in lead exposed mice was significantly lower than controls at effector to target cell ratios of 100:1, 50:1, and 25:1. In contrast, no significant difference in unstimulated NKMC was seen in lead exposed mice and control mice at effector to target cell ratios of 200:1, 100:1, and 50:1. Moreover, in vivo poly I:C-enhanced NKMC in lead-treated mice was similar to controls at an effector to target cell ratio of 200:1. Blood lead levels averaged 40.5 +/- 1.2 micrograms% in lead-exposed mice and 1.9 +/- 0.3 micrograms% in controls. These findings suggest that chronic low-level lead exposure in mice results in significant suppression of ADCC (CRBC) but does not alter natural killer activity.