Centre Interdisciplinaire Chimie Biologie 1 article published in JoVE Immunology and Infection Isolation of Tonsillar Mononuclear Cells to Study Ex Vivo Innate Immune Responses in a Human Mucosal Lymphoid Tissue Nikaïa Smith1,2,3,4, Nassima Bekaddour2,3,4, Nicolas Leboulanger4,5, Yolande Richard*6, Jean-Philippe Herbeuval*2,3,4 1Institute of Molecular Virology, Ulm University Medical Center, 2CNRS UMR-8601, Centre Interdisciplinaire Chimie Biologie, 3Team Chemistry & Biology, Modeling & Immunology for Therapy, Université Paris Descartes, 4Université Paris Descartes, Sorbonne Paris Cité, 5Pediatric Otolaryngology Department, Hôpital Necker-Enfants Malades, Assistance Publique Hôpitaux de Paris, 6Université de Paris, Institut Cochin In the present protocol, we explain how to easily process and culture tonsillar mononuclear cells from healthy humans undergoing partial surgical tonsillectomy to study innate immune responses upon activation, mimicking viral infection in mucosal tissues.