What are the functions Langerhans cells?

Langerhans cells also have a role in suppressing immune function. Friendly bacteria naturally exist on the skin, and in the presence of non-pathogenic bacteria, Langerhans cells induce immune tolerance and prevent the immune system from responding. This is significant as it prevents unnecessary and harmful activation of the immune system. Langerhans cells also assist in preventing autoimmunity through promoting immune tolerance. Under normal conditions when no pathogenic bacteria are present, these cells promote the activation of T-regulatory cells in the skin. T-regulatory cells secrete cytokines which promote immune tolerance. In the presence of pathogens, Langerhans cells promote the activation of effector T cells and restrict the activation of T-regulatory cells. They stimulate the effector cells (e.g. cytotoxic T cells) to generate an immune response and clear infections from the skin.