Characterization of human endotoxin lipopolysaccharide receptor CD14 expression in transgenic mice

CD14 is a major receptor for the bacterial endotoxin LPS. Since CD14 is specifically and highly expressed on the surface of monocytic cells, it has been used as a monocyte/macrophage differentiation marker. To identify elements that are critical for the direction of the tissue-specific expression of CD14, an 80-kb genomic DNA fragment containing the coding region of the CD14 gene, as well as a considerable amount of both upstream and downstream sequence, was used to generate transgenic mice. The analysis of mice from six different founder lines demonstrated that this genomic DNA fragment was sufficient to direct human CD14 gene expression in a monocyte-specific manner among hematopoietic cells. Furthermore, the data lead us to a new finding that CD14 is highly expressed in the human liver, a primary organ involved in the acute phase response. These transgenic mice provide a useful model to analyze the biological function of human CD14.