Abstract
The abilities of human epidermal Langerhans cells and peripheral blood macrophages to induce specific T-lymphocyte responses to purified protein derivative (PPD), herpes simplex virus and nickel sulfate were compared. On a cell to cell basis the Langerhans cells were about as potent as adherent cells in inducing T-cell responses to PPD, more potent in inducing responses to herpes simplex virus, and several times more potent in inducing responses to nickel. Human epidermal Langerhans cells seem highly specialized in antigen presentation, particularly for nickel sulfate. They may play an important role in inducing contrast sensitivity dermatitis.