Transplantation of tissues/organs to save certain patients often fails due to rejection of such tissues/organs by the patient. Which type of immune response is responsible for such rejections?

Transplantation is the procedure of replacing the unhealthy organ with a healthy one in an individual. Sometimes these replaced organs get rejected by the body’s immune system as they are considered as a foreign object by the body. In response to this, cell mediated immune response takes place by T-Lymphocytes. These lymphocytes try to differentiate between self cells and foreign cells because of which sometimes the graft gets rejected.