Resident Macrophage Lookalikes of Unexpected Origin

In this issue of Developmental Cell, Lin et al. (2019) Lin X. Zhou Q. Zhao C. Lin G. Xu J. Wen Z. An ectoderm-derived myeloid-like cell population functions as antigen transporters for Langerhans cells in zebrafish epidermis. Dev. Cell. 2019; 49 ( this issue) : 605-617 Google Scholar identify in zebrafish skin macrophage-like cells that sample the environment through transepithelial protrusions and import antigen from the water for traditional tissue-resident macrophages. Remarkably, these “metaphocytes” originate from the epidermis, challenging current assumptions about the lineage of tissue-resident macrophages