Is organ rejection a negative feedback loop?
1) “Negative feedback occurs when the output of a system acts to oppose changes to the input of the system; with the result that the changes are attenuated. If the overall feedback of the system is negative, then the system will tend to be stable.” Source and further information: http://en.wikipedia.org/wiki/Negative_feedback So in a way, you could say that the body “reacts negatively” to the transplant. 2) “Regulatory T cells (sometimes known as suppressor T cells) are a specialized subpopulation of T cells that act to suppress activation of the immune system and thereby maintain immune system homeostasis and tolerance to self-antigens. The existence of a dedicated population of suppressive T cells was the subject of significant controversy among immunologists for many years. However, recent advances in the molecular characterization of this cell population have firmly established their existence and their critical role in the vertebrate immune system.
