Humans and mice have a variety of professional antigen-presenting cells. Bone marrow–derived myeloid precursors produce heterogeneous populations that arise under homeostatic settings or are induced by inflammation, yet distinguishing classical dendritic cells (cDCs) from monocytes, macrophages and plasmacytoid DCs remains problematic, as these all express the DC marker CD11c. In the Journal of Experimental Medicine, two reports by Nussenzweig and Murphy and their colleagues identify Zbtb46 (BTBD4 in humans) as a zinc-finger transcription factor expressed in pre-cDCs and cDCs but not in plasmacytoid DCs or cells of other myeloid lineages. Zbtb46 itself is not needed for the generation of cDCs, but it represses the expression of receptors for growth factors for alternative myeloid lineages. Conditional depletion of Zbtb46+ cells identifies a central role for cDCs in eliciting T helper type 1 responses, but immunity to tumors or Toxoplasma is impaired only partially. Zbtb46 thus serves as a specific marker for distinguishing cDCs and their functional activities.

J. Exp. Med. (21 May 2012) doi:10.1084/jem.20112675 & doi:10.1084/jem.20120030