| Abstract: | Cutaneous basophil hypersensitivity (CBH) reactions are a heterogeneous group of delayed time course basophil-rich immune responses that can be mediated in the guinea pig by T cells, B cells, or IgG1 antibody. This study examined whether guinea pig IgE antibody could also mediate CBH reactions. IgE antibody to picryl or oxazolone determinants was induced by immunizing Hartley strain guinea pigs pretreated with cyclophosphamide. Hyperimmune serum from these animals was passed through a heavy chain-specific anti-IgG1 affinity column. The presence of IgE anti-hapten antibody in the filtrate fraction was verified by passive cutaneous anaphylaxis (PCA) testing with a 7-day period of local passive sensitization and by the heat lability (56 degrees C, 4 hr) of PCA activity. This IgE-rich fraction and the IgG1 fraction eluted from the column with base (0.2 M Na2CO3, pH 11.3) were transferred i.v. to separate groups of normal guinea pigs. Both fractions mediated delayed time course reactions that contained basophils. Macroscopic and microscopic reactions mediated by the IgE-rich fraction were abolished with heat (56 degrees C, 4 hr). Thus, two antigen-specific factors in guinea pig serum can mediate delayed time course basophil-containing reactions: IgG1 and IgE antibodies. IgE-mediated CBH reactions are similar to the late-phase reaction that follows IgE-dependent wheal-and-flare reactions in humans. The finding that guinea pig IgE can mediate a late reaction that contains basophils makes this a possible model for the human late-phase response, and suggests that some forms of CBH may play a role in human allergic disease. |
