Jack and Jill were badly burned in an accident at the well and both were taken to the burn unit of the local hospital. The burns covered only a small area of skin so grafts were prepared for both patients from the skin of Jack's thigh. Jack's graft was successful and his burn healed completely. Jill, however, rejected the grafted skin. Explain the immune responses of both patients to these grafts. What treatments could have helped Jill to avoid rejection of her graft?