Lead intoxication impairs the generation of a delayed type hypersensitivity response

The effect of oral administration of lead, as Pb-acetate, via the drinking water on the murine delayed type hypersensitivity (DTH) response was invest igated. The DTH response of BALB/c mice sensitized intraveneously with shee p red blood cells (SRBC) was found to be suppressed markedly in lead-intoxi cated mice. Suppression of the DTH correlated with increasing blood Pb conc entration. Suppression of the DTH response by Pb intoxication depended on t he route of administration of the sensitizing antigen, as Pb intoxication d id not impair the DTH reaction when mice were sensitized to SRBC via intrap eritoneal injection. Since DTH reactions are regulated in large part by Th1 cells, these data establish an in vivo model system based on a rational ro ute of Pb exposure in which to study further the modulation of Th1-mediated immune effector function by Pb. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.