Title: IgE Effector Mechanisms, in Concert with Mast Cells, Contribute to Acquired Host Defense against Staphylococcus aureus
Author: Philipp Starkl, Martin L. Watzenboeck, Lauren M. Popov, Sophie Zahalka, Anastasiya Hladik, Karin Lakovits, Mariem Radhouani, Arvand Haschemi, Thomas Marichal, Laurent L. Reber, Nicolas Gaudenzio, Riccardo Sibilano, Lukas Stulik, Frédéric Fontaine, André C. Mueller, Manuel R. Amieva, Stephen J. Galli, Sylvia Knapp
Abstract: Allergies are considered to represent mal-directed type 2 immune responses againstmostly innocuous exogenous compounds. Immunoglobulin E (IgE) antibodies are a characteristicfeature of allergies and mediate hypersensitivity against allergens through activationof effector cells, particularly mast cells (MCs). Although the physiological functionsof this dangerous branch of immunity have remained enigmatic, recent evidence showsthat allergic immune reactions can help to protect against the toxicity of venoms.Because bacteria are a potent alternative source of toxins, we assessed the possiblerole of allergy-like type 2 immunity in antibacterial host defense. We discoveredthat the adaptive immune response against Staphylococcus aureus (SA) skin infection substantially improved systemic host defense against secondarySA infections in mice. Moreover, this acquired protection depended on IgE effectormechanisms and MCs. Importantly, our results reveal a previously unknown physiologicalfunction of allergic immune responses, IgE antibodies, and MCs in host defense againsta pathogenic bacterium.