Guinea-pig anaphylaxis mediated by monovalent haptens with hydrocarbon auxiliary groups: studies on the difference in elicitation between intradermally and intravenously administered hapten.

A well defined group of monovalent haptens has been found to elicit rather than to inhibit anaphylactic reactions. In essence, these compounds contain lysine or 1,6-diaminohexane as carrier, a single DNP- or DNCP-haptenic group on one of the two amino functions and an auxiliary hydrocarbon moiety on the second amino function. With N-DNCP-N-BPO-diaminohexane it was found that DNCP-specific passive cutaneous anaphylaxis (PCA) could be elicited only by intravenous injection of the hapten into animals intradermally sensitized by anti-DNCP antiserum. No elicitation took place when sensitization was by the intravenous route and the hapten given intradermally. When sensitization was by intradermal injection of antiserum, intradermally applied monovalent hapten was an elicitor only at extremely high doses. On the other hand anaphylactic reactions were readily evoked when both passive sensitization and monovalent elicitation were carried out by the intravenous route. It is thus established that the mode of application of the monovalent hapten and not the route of passive sensitization determines whether monovalent elicitation is effective. Accordingly, the difference in elicitation behaviour cannot be due to different susceptibilities of the different vasoactive cells involved. Monovalent elicitation of anaphylactic reactions with N-DNCP-N-BPO-diaminohexane is very similar in guinea-pigs passively sensitized with either rabbit or homologous antisera. It is not impaired in animals pretreated with cobra venom factor, a finding that rules out the participation of complement. Histamine release from guinea-pig lung fragments cannot be observed even in the presence of high concentrations of autologous serum. The assistance of a serum component in monovalent elicitation is therefore unlikely.