Eosinophil innate immune memory after bacterial skin infection promotes allergic lung inflammation
Mariem Radhouani, Asma Farhat, Anna Hakobyan, Sophie Zahalka, Lisabeth Pimenov, Alina Fokina, Anastasiya Hladik, Karin Lakovits, Jessica Brösamlen, Vojtech Dvorak, Natália Nunes, Andreas Zech, Marco Idzko, Thomas Krausgruber, Joerg Koehl, Özge Uluçkan, Jiří Kovařík, Kai Hoehlig, Axel Vater, Margret Eckhard, Andy Sombke, Nikolaus Fortelny, Jörg Menche, Sylvia Knapp, Philipp Starkl
Abstract
Microbial exposure at barrier interfaces drives development and balance of the immune system, but the consequences of local infections for systemic immunity and secondary inflammation are unclear. Here, we show that skin exposure to the bacterium Staphylococcus aureus persistently shapes the immune system of mice with specific impact on progenitor and mature bone marrow neutrophil and eosinophil populations. The infection-imposed changes in eosinophils were long-lasting and associated with functional as well as imprinted epigenetic and metabolic changes. Bacterial exposure enhanced cutaneous allergic sensitization and resulted in exacerbated allergen-induced lung inflammation. Functional bone marrow eosinophil reprogramming and pulmonary allergen responses were driven by the alarmin interleukin-33 and the complement cleavage fragment C5a. Our study highlights the systemic impact of skin inflammation and reveals mechanisms of eosinophil innate immune memory and organ cross-talk that modulate systemic responses to allergens.