[Langerhans' cell]

Abstract

Our knowledge of the Langerhans cell has benefited much from improvements in identification techniques (notably dopa reaction and detection of ATPase), from the demonstration of Birbeck's granules at electron microscopy and from the finding of various membrane antigens, including the T6 antigen revealed by a monoclonal antibody. This antibody facilitates immunolabelling of skin sections and isolation of Langerhans cells from suspensions of epidermal cells. The Langerhans cell belongs to the histiomonocytic line; it originates in the bone marrow whence it migrates to colonize the granular layer of the epidermis. The stress is now placed on the immunological functions of these cells. They may bear haptens with DR restriction, i.e. in syngeneic situation. Treatment of the skin with ultraviolet rays, which destroy or inhibit the Langerhans cells, induces experimental tolerance to haptens. In the mixed lymphocytes-epidermal cells model, the treatment of suspensions with ultraviolet rays and/or monoclonal anti-Langerhans cell antibodies suppresses allergenic stimulation. These results offer hopes of practical applications in different fields.