Which type of immune response is responsible for the rejection of tissue/ organs in the patients's body post transplantation ?

Cell-mediated immune response .

Grafts from just any source – an animal, another primate, or any human beings cannot be made since the grafts would be rejected sooner or later. Tissue matching, blood group matching are essential before undertaking any graft/transplant and even after this the patient has to take immuno–suppresants all his/her life. The body is able to differentiate ‘self’ and ‘nonself’ and the cell-mediated immune response is responsible for the graft rejection.