Cloning, characterization and mapping of porcine CD14 reveals a high conservation of mammalian CD14 structure, expression and locus organization

The cell surface protein CD14 plays a central role in innate immunity as a pattern recognition receptor. CD14 is part of a receptor complex also including toll-like receptor 4 and MD2 proteins. Binding of the ligand lipopolysaccharide to the complex on myeloid cells leads to release of pro-inflammatory cytokines and mediators from the cell. In this study, we present the cloning, characterization and tissue expression pattern of a porcine CD14 encoding cDNA, and the chromosomal localization of the porcine CD14 gene. The open reading frame is predicted to encode a protein of 373 amino acids, which shows conservation of structural as well as functional regions when compared to other mammalian species. The CD14 gene was localized to porcine chromosome 2 in a region syntenic to human chromosome 5q. Transcription analysis shows that CD14 is widely expressed in tissues examined in this study, which correlates well with expression primarily on myeloid cells.