Tolerance can be induced by using antidiotypic Abs against T cells. The antidiotypic Abs bind to T cells and prevent receiving stimulation from graft antigens.
As there is no stimulation from graft, T cells remain calm with out inducing any reaction against the graft. This technique sounds good but not easy to apply practically, because maintenance of high levels of antibodies for an extended period of time in order to maintain tolerance to the transplanted tissue is not an easy task.
A treatment that is currently feasible and successful in some types of human transplantation is immune enhancement. Pre immunization with donor’s antigens gradually raises tolerance to the graft.
In this method the Abs raised through pre immunization might bind the passenger cells of the graft and destroy them before they can induce the recipient T ells or the Abs raised may be non compliment fixing, hence their binding to antigens block interaction of lymphocytes with graft antigens.