Sensitization of Guinea Pigs to Alpha-Chloroacetophenone (CN) and Ortho-Chlorobenzylidenemalononitrile (CS), Tear Gas Chemicals

摘要

The most frequently used tear gas ingredients, 1-chloroacetophenone (CN) and o -chlorobenzylidenemalononitrile (CS), caused contact sensitization or delayed hypersensitivity in guinea pigs by either a topical or intradermal route of administration with the aid of Freund's complete adjuvant (FCA). CN was allergenic even without the aid of FCA, was more irritating to skin than CS and was also more irritating to skin and more allergenic when administered as Chemical Mace than in acetone at equivalent concentrations. Upon intradermal challenge, the skin reactions of sensitized guinea pigs to CN showed erythema, edema, induration and occasional necrosis. The skin reactions developed by topical challenges were similar but resulted also in eschar formation. CN and CS, especially CS, showed a specificity for routes of immunization, namely, a better rate of elicitation in incidence and degree of allergic skin reactions when immunization and challenge routes were identical. The guinea pigs sensitized to CN showed cross-reactivity to 1-bromoacetophenone, 1,1-dichloroacetophenone and acetophenone in the order listed. Strongly sensitized animals showed weak cross-reactions whereas weakly sensitized guinea pigs gave no or negligible cross-reactivity to acetophenone derivatives having three fluorine atoms, a nitrile, acetyl or N-benzamidyl group at the 1 position or one halogen at one of the ring positions; ethane or acetone bearing three chlorines at the 1 position; DM (phenarzine chloride); or ethyl chloroformate.