Anaphylactic reactions to univalent haptens.

The question whether a univalent antigen may suffice for the elicitation of anaphylactic reactions is the subject of this study. We previously reported that certain univalent alpha substituted ε-DNP-lysine compounds can elicit such reactions. Evidence on this question has been extended to include the use of a number of aliphatic as well as a cyclic α substituent in ε-DNP-lysine. The haptens most active in eliciting PCA responses were the 8 and 10 C α-acyl derivatives. A cyclic acyl compound (α-hexahydrobenzoyl-ε-DNP-lysine) was inactive. A hypothesis is advanced to account for the release of histamine from the cells of sensitive animals by simple (1:1) complexing of antigen with antibody, based upon the structures and activities of the compounds tested.