Neutrophils culturedex vivofrom CD34+stem cells are immature and genetically tractable

Neutrophils are essential antimicrobial effector cells with short lifespans. During infection or sterile inflammation, accelerated production and release of immature neutrophils from the bone marrow serves to boost circulating neutrophil counts. To facilitate the study of neutrophil development and function, we optimised a method for ex vivo production of human neutrophils from CD34 + haematopoietic progenitors. We obtain high yields of neutrophils, which phenotypically resemble immature neutrophils released into the circulation upon administration of GCSF to healthy donors. We show that ex vivo differentiated immature neutrophils have similar rates of ROS production but altered degranulation, cytokine release and antifungal activity compared to mature neutrophils isolated from peripheral blood. We demonstrate that ex vivo cultured neutrophils are genetically tractable via genome editing of precursors and thus provide a powerful model system for investigating the properties and behaviour of immature neutrophils.