THORAX ABDOMEN AND PELVIS

Detailed explanation-1: -The immune system White blood cells normally attacks foreign tissue, including transplants. This reaction is called rejection . Rejection is triggered when the immune system recognizes certain molecules on the surface of a cell as foreign.

Detailed explanation-2: -The immune system’s white blood cells make specific proteins called antibodies and special cells called T cells that destroy the foreign cells. A transplanted organ is made entirely of cells with foreign (“nonself”) antigens which means the body will attack the transplanted organ.

Detailed explanation-3: -In most cases, adaptive immune responses to the grafted tissues are the major impediment to successful transplantation. Rejection is caused by immune responses to alloantigens on the graft, which are proteins that vary from individual to individual within a species, and are thus perceived as foreign by the recipient.

Detailed explanation-4: -The immune response to a transplanted organ consists of both cellular (lymphocyte mediated) and humoral (antibody mediated) mechanisms. Although other cell types are also involved, the T cells are central in the rejection of grafts. The rejection reaction consists of the sensitization stage and the effector stage.