In practical terms, when your body is invaded by an alien organism, the dendritic cells take a piece of the organism and display it to soldiers and generals to determine if attack is warranted. The dendritic cells roam the Festival of Life, brushing up against guests at the packed affair, and presenting their identities to the T cells. If an antigen were perceived as foreign, it would stimulate a heavy response, what is known as a mixed leukocyte reaction, or MLR, a major inflammation of T cells and B cells and other immune cells.
