IgE as Adjuvant in Tumor Vaccination

Activation of the antigen-IgE-Fc epsilon RI axis results in a potent inflammatory state. The redirection of this IgE-mediated activation of the immune system from allergic reactions toward tumors is the main theme of the new AllergoOncology field. Our particular approach has been to employ IgE as an adjuvant in anti-tumor vaccination. IgE-coated tumor cells can protect against tumor challenge, an observation that supports the involvement of IgE in anti-tumor immunity. The adjuvant effect of IgE was shown to result from eosinophil-dependent priming of the T-cell-mediated adaptive immune response. Moreover, the role of Fc epsilon RI in IgE anti-tumor adjuvanticity has been recently demonstrated. The interaction of tumor cell-bound IgE with receptors triggers the release of mediators with following recruitment of effector cells, cell killing and tumor antigen cross-priming. Starting from these evidences, several improvements toward a simple and universal use of IgE in anti-tumor cellular vaccines have been accomplished. In view of narrowing the gap between experimental models and therapeutic applications, the field is now shifting toward a humanized systems, employing human IgE and human Fc epsilon RI alpha transgenic mice