Langerhans cells in porcine skin.

Langerhans cells (LCs) are resident dendritic cells (DCs) of skin and mucosal epithelium. The standard for identifying skin DCs as LCs is expression of langerin (CD207), a surface protein that mediates Birbeck granule (BG) formation upon internalization. Reports of BGs in porcine skin DC are contradictory, due to lack of langerin detection. Here, we present the sequence of porcine langerin/CD207, showing that the predicted porcine protein shares 75%/86% amino acid identity/similarity with human. Langerin mRNA was detected in porcine skin DCs by PCR and langerin protein was detected in both isolated skin DCs and skin sections by immunostaining. Approximately, 50-70% of skin DCs expressed langerin, demonstrating that the majority of porcine skin DCs are LCs. The full length sequence combined with the identification of antibodies reactive with porcine langerin, facilitates the study of LCs in swine, and advances the use of swine for studying skin diseases and infectious disease processes involving skin.