Though the specificity of the acquired immune system makes it the focus of more research than its innate counterpart, it must be remembered that these two arms of the immune system are interrelated and dependent upon one another for proper function. The two features which define the acquired immune system are its specificity and its memory. It is able to distinguish foreign cells from self, and can distinguish one foreign antigen from another. The second feature of the specific immune system, memory, is what allows immunization and resistance to reinfection with the same microorganism. Once acquired immune cells have encountered particular organism, they are able to persist and convey resistance to that organism for an extended period of time.
T cells serve two roles.
The first is as the coordinator of other acquired immune responses, a task accomplished by their production of a wide variety of cytokines and surface cell signals. The second is as the primary responder to long term intracellular infections. T Cells T cells are responsible for destroying infected or cancerous cells, and for coordinating all acquired immune responses. For this reason T cell immunity is generally called cellular immunity. Almost all the cells in one's body are constantly producing MHC and attaching small internal proteins to it for expression on their surface.