History of IgE Receptors on Eosinophils

Early studies on the killing of schistosomula in vitro by human eosinophils involved the use of cells purified from normal or slightly eosinophilic individuals. 

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However, this seemingly strong association between human and rat eosinophils and IgE-mediated diseases has been unclear in mice. For example, analyses of the effects of antibodies to IL-5 on helminth-induced eosinophilia have shown that anti-IL-5 suppresses blood eosinophilia and eosinophil infiltration into the tissues of parasitized animals. However, ablation of eosinophilia by anti-IL-5 was not associated with a diminution of resistance in mice infected with S. mansoni (26) or with Trichinella spiralis (27). These findings suggest that eosinophils are not involved in the expression of immunity to these parasites, at least in these mouse models. In contrast, mice infected with Trichuris muris showed the exactly opposite findings. In this infection, the resistance to infection was associated with the production of Th2 cytokines, such as IL-4 and IL-5, tissue eosinophilia, and intestinal IgA production (28). Furthermore, in murine asthma models, the experiments using anti-IL-5 showed that neither IL-5 nor eosinophils were required for airway hyperresponsiveness in BALB/c mice sensitized and challenged with 

Low-Affinity igE Receptor (Fc8Rii/CD23) on Human Eosinophiis 

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