Immune function is not impaired in Sprague-Dawley rats exposed to dimethyltin dichloride (DMTC) during development or...

Organotins are used commercially as pesticides, antifouling agents and stabilizers for polyvinyl chloride (PVC) pipe. Mono- and di-substituted butyltins, used in PVC pipe production, are of concern to the US EPA because they leach from supply pipes into drinking water and are reported multisystem toxicants. We assessed several immune functions in Sprague-Dawley rats after adult or developmental dimethyltin dichloride (DMTC) exposure because various organotins have been reported to be immunotoxic. Adult male and female rats were given drinking water containing 0, 20 or 40 mg DMTC/L (0, 1.7, or 3.4 mg DMTC/kg body weight [BW]) for 28 days. Pregnant females were given the same DMTC drinking water concentrations for a total of 37 days, from gestational day (GD) six through weaning of pups (0, 2.4, or 4.6 mg DMTC/kg BW during gestational exposure; 0, 3.6, or 6.9 mg DMTC/kg BW during postnatal exposure). On postnatal day (PND) two, litters were sexed, weighed, and culled to four males and four females per dam. Delayed-type hypersensitivity (DTH), antibody synthesis, and natural killer (NK) cell activity were evaluated in adults (N=8/sex/group) and in immunologically mature offspring (N=6/sex/group). Although water consumption was decreased in all of the DMTC dose groups, the immune functions evaluated were not affected. Our data suggest that these immune functions are not sensitive to the levels of DMTC anticipated to occur in drinking water delivered via PVC pipe as the concentrations we used were several orders of magnitude higher than those expected to leach from PVC pipes.