Immunohistochemical localization of Toll-like receptor 2 in skin Langerhans' cells of striped dolphin (Stenella coeruleoalba).

The skin is the primary interface between the body and the environment, and has a central role in host defence. In the epidermis, Langerhans' cells form an interconnecting network of dendritic cells, that play a central role within inflammatory and immune responses of terrestrial and aquatic mammals, but few studies aimed at their characterization have been carried out in cetaceans, so far. Toll-like receptors are crucial players in the innate immune response to microbial invaders. These receptors are expressed on immune cells, such as monocytes, macrophages, dendritic cells, and granulocytes. The aim of this preliminary study was to describe the expression of Toll-like receptor 2 in a stranded striped dolphin (Stenella coeruleoalba) skin. Immunoreactive cells were predominantly found within the stratified squamous epithelium. Other Toll-like receptor 2 positive cells of varying morphology, were found, and may help to increase the knowledge on the interaction occurring between dolphins and the environment in which they live at their most crucial interface: the skin.