Antigen Presenting Cells (APCs)

Antigen presenting cells play a key role in the immune system as they are the only cells of the body that are able to trigger antigen-specific immune responses upon infection with foreign invaders. Three differentially specialized types of cells are in charge of this vital task: dendritic cells, macrophages, and to a certain extent, B lymphocytes. We are beginning to understand the molecular mechanisms of how these cells take up, process, and present antigens and how this translates into T-cell activation or silencing. This knowledge is fundamental for both our current concepts about how the immune system discriminates between self and nonself and for the development of novel vaccination strategies against diseases still threatening mankind.