A critical role for eotaxin in experimental oral antigen-induced eosinophilic gastrointestinal allergy

SP Hogan, A Mishra, EB Brandt… - Proceedings of the …, 2000 - National Acad Sciences
Proceedings of the National Academy of Sciences, 2000National Acad Sciences
Despite marked advances in the understanding of allergic responses, the mechanisms
regulating gastrointestinal allergy are not very well understood. We have developed a model
of antigen-induced eosinophil-associated gastrointestinal allergy and characterized the role
of eotaxin and IL-5. Challenge of allergen-sensitized mice with oral allergen, in the form of
enteric-coated beads, resulted in marked allergen-specific IgG1 and IgE, Th2-type (IL-4 and
IL-5) cytokine production, and eosinophil accumulation in the blood and small intestine. In …
Despite marked advances in the understanding of allergic responses, the mechanisms regulating gastrointestinal allergy are not very well understood. We have developed a model of antigen-induced eosinophil-associated gastrointestinal allergy and characterized the role of eotaxin and IL-5. Challenge of allergen-sensitized mice with oral allergen, in the form of enteric-coated beads, resulted in marked allergen-specific IgG1 and IgE, Th2-type (IL-4 and IL-5) cytokine production, and eosinophil accumulation in the blood and small intestine. In the genetic absence of eotaxin, a chemokine constitutively expressed in the gastrointestinal tract, eosinophil recruitment into the small intestine was ablated, and these mice developed enhanced eosinophil accumulation in the blood compared with wild-type mice. Interestingly, in the absence of IL-5, allergen challenge promoted partial eosinophil accumulation into the small intestine and a decline in circulating eosinophil levels. Collectively, these results establish that the accumulation of gastrointestinal eosinophils is antigen induced, can occur independent of IL-5, and provides a molecular mechanism to explain the dichotomy between peripheral blood and tissue eosinophilia. Furthermore, eotaxin is identified as a critical regulator of antigen-induced eosinophilic inflammation in the gastrointestinal tract.
National Acad Sciences