Caption: Dendritic and T-cells. Coloured Scanning Electron Micrograph (SEM) of two types of protective cell of the human immune system. A large dendritic or Langerhans cell is seen (at lower right) with a T cell attached (at upper left). Dendritic cells are found in the skin. They recognise foreign proteins (antigens) and ingest them into cytoplasmic Birbeck granules. Antigens are then "processed" and secreted out of the cell, to be dealt with by other immune cells.