Lentil lectin effectively induces allotransplantation tolerance in mice.

The interaction of lectins with carbohydrate receptors on the plasma membrane of eukaryotic cells results in a wide variety of biological effects. One effect which has been extensively studied is the stimulation of lymphocytes to blastogenesis and proliferation. High doses of concanavalin A (Con A) and phytohaemagglutinin (PHA) have been shown to activate in vitro regulatory cells capable of suppressing proliferation of other cells in the culture. However, Con A and PHA treatment were used effectively to prolong the survival of skin and heart allografts before it was recognised that some lectins have an activatory effect on suppressor cells in vitro. A possible explanation of these tolerogenic effects is the activation of specific suppressor cells. In this letter we have compared systematically various lectins differing in their carbohydrate specificity and mitogenicity in relation to their ability to induce prolonged skin allograft survival in mice with the aim of selecting the most effective lectin tratment schedule. Some preliminary results of this study have been mentioned in a recent review.