In vivo assay of IgE activities on the expulsion of intestinal adult worms

- Immune sera are collected from Strongyloides venezuelensis-infected mice.
- Purification and concentration of IgE from immune sera are done by a versatile method.
- An injection of immune serum-derived IgE elicits adult worm expulsion from the small intestine.

A physiological role of immunoglobulin E (IgE) is to promote parasitic helminth expulsion. This assertion is largely based on a series of studies carried out by Capron's laboratory. They observed that IgE is an essential component of protective immunity against Schistosoma mansoni larvae both in vitro and in vivo. Then, another group reported that IgE-deficient mice show higher worm burdens than wild-type (WT) mice when mice are infected with Trichinella spiralis. Although these studies indicate anti-helminth activities of IgE targeted on larvae forms, they do not prove the fighting effects of IgE on adult worms. In contrast, a recent study demonstrates an expelling activity of IgE for adult worms through an adoptive transfer of immune serum-derived IgE into Strongyloides venezuelensis-infected mice. Here, I describe how IgE is purified from S. venezuelensis-immune sera and is transferred into infected mice to examine its effect on worm expulsion. This method will be used to advance our understanding the mechanism of S. venezuelensis expulsion and explore S. venezuelensis antigens recognized by IgE. Moreover, adoptive transfers of IgE purified from immune sera will be applicable to other helminth infection models to investigate physiological roles of IgE.

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