FLT3 and infection: Compared to CSF1R-tghigh cells from uninfected birds many DC related genes were not upregulated in APEC-infected birds (FLT3, CADM1, CIITA, CCR7, XCR1), indicating that APECposCSF1R-tghigh cells were enriched for macrophages, likely recruited from the circulation due to strong inflammatory signals produced by epithelial cells and resident innate cells in the lung to limit the infection.