Ligation of IgE receptors causes an anaphylactic response and neutrophil infiltration but does not induce eosinophilic inflammation in mice

Background: Eosinophils are selectively recruited into the tissues during chronic allergic inflammation. IgE is considered an initiator of the allergic reaction; however, the roles of IgE in allergic inflammation are not fully understood. Objective: We tested the hypothesis that antigen interaction with specific IgE antibody provokes eosinophilic inflammation. Methods: BALB/c mice were actively sensitized with ragweed extract and passively sensitized with anti-dinitrophenyl (anti-DNP) mouse IgE and challenged intraperitoneally by injecting either ragweed extract or DNP-ovalbumin (OVA). Immediate anaphylactic responses were examined by monitoring vascular permeability and by measuring histamine content in peritoneal lavage fluids. Late-phase allergic responses were examined by total cell counts and cell differentials. Results: Mice sensitized and challenged with ragweed showed immediate anaphylactic responses followed by temporal increases in neutrophils at 3 to 12 hours and sustained ncreases in eosinophils in their peritoneal cavities after 24 hours. Double-sensitized mice (ie, sensitized actively for ragweed and passively for DNP-OVA) challenged with ragweed showed immediate anaphylactic responses and peritoneal eosinophilia at 48 hours. Double-sensitized mice challenged with DNP-OVA showed comparable immediate anaphylactic responses but no peritoneal eosinophilia. Furthermore, at 8 hours, ragweed-challenged animals recruited both eosinophils and neutrophils, but DNP-OVA–challenged animals recruited only neutrophils. Finally, after active sensitization and challenge with ragweed, mast cell–deficient mice (WBB6F1-W/W^v) lacked the immediate response but showed comparable eosinophil accumulation as their litter mate controls (WBB6F1-+/+). Conclusion: Interaction of antigen with IgE antibody is insufficient to provoke eosinophilic inflammation in mice. (J Allergy Clin Immunol 2000;105:1202-10.)