OPTION 1

•            Langerhans cells are dendritic cells located among keratinocytes at all suprabasal levels .

•            They belong to the mononuclear phagocyte system (reticuloendothelial system) as modified monocytes derived from the bone marrow.

•            They contain elongated granules and are considered macrophages with possible antigenic properties.

•            Langerhans cells have an important role in the immune reaction as antigen- presenting cells for lymphocytes.

•            They contain g-specific granules (Birbeck’s granules) and have marked adenosine triphosphatase activity.

•            They are found in oral epithelium of normal gingiva and in smaller amounts in the sulcular epithelium; they are probably absent from the junctional epithelium of normal gingiva.