part of stratum spinosum Langerhans cell BTO:0000705 BrendaTissueOBO Stellate dendritic cells, derived from precursors in the bone marrow, that appear clear on light microscopy and have a dark-staining, indented nucleus and characteristic inclusions (Birbeck granules) in the cytoplasm, they lack tonofilaments, desmosomes, and melanosomes. Langerhans' cells are found principally in the stratum spinosum of the epidermis, but they also occur in other stratified epithelia and have been identified in the lung, lymph nodes, spleen, and thymus. They have surface markers characteristic of macrophages and are believed to be antigen-presenting cells involved in contact allergic responses and other cell-mediated immune reactions in the skin. macrophage epidermal cell