Steffen Jung received my PhD at the Institute of Genetics in Cologne, where he used the then newly developed gene targeting approach to define cis-acting control elements driving non-coding ‘sterile’ transcripts in immunoglobulin class switch recombination. In 1993, he moved for post-doctoral training to Israel studying transcription factors and kinases in T cell signaling. In 1997, He went to New York for a post-doc at the Skirball Institute for Molecular Pathogenesis, NYU Medical Center. His studies there focused on the chemokine receptor CX3CR1 and its membrane-tethered ligand CX3CL1/ fractalkine. He generated CX3CR1gfp mice that became as reporter strain instrumental to define murine monocyte subsets and study microglia. Furthermore, he was involved in the development of a novel diphtheria toxin receptor (DTR) -based cell ablation strategy establishing a mouse model that allowed to define in vivo functions of dendritic cells (DC) by their conditional ablation. In 2002, Steffen Jung returned to Israel and joined the faculty of the Department of Immunology at the Weizmann Institute, where he received tenure in 2009 and full professorship in 2015. Current work of the Jung lab aims at elucidating in vivo aspects of mononuclear phagocytes, including the definition of developmental pathways and differential functions of monocytes, DC and macrophages. Specifically, the team applies intra-vital imaging, conditional cell and gene ablation and precursor graft-mediated reconstitution, combined with advanced genomic analysis to investigate the biology of these cells in physiological context in health and disease. Recent work of the Jung laboratory focuses on the study of monocyte-derived intestinal macrophages, embryonic-derived brain microglia and lymph node DC, as well as the role of macrophages in metabolic disorders.