Comparative toxicity of mono- and bifunctional alkylating homologues of sulphur mustard in human skin keratinocytes.

Sulphur mustard (bis(2-chloroethyl) sulphide; agent H) is a vesicant chemical warfare (CW) agent whose mechanism of action is not known with any certainty and for which there are no effective antidotes. It has a pronounced latent period before signs and symptoms of poisoning appear which it shares with the nitrogen mustards, and that differentiates it from other classes of vesicant agents. Sulphur mustard, the sulphur mustard CW agents Q (1,2-bis(2-chloroethylthio) ethane) and T (1,1 bis(2-chloroethylthioethyl) ether), the H partial hydrolysis product hemi-sulphur mustard (2-chloroethyl 2-hydroxyethyl sulphide; HSM), and the commercially available 2-chloroethyl ethyl sulphide (CEES) were characterized with respect to their toxicity in first passage cultures of proliferating human skin keratinocytes, the target cell of H-induced skin vesication.