T-CELL REGULATION IN ADULT TRANSPLANTATION TOLERANCE

An encounter of the mature immune system with Ag usually leads to an i mmune response. If Ag is administered with CD4- and CD8-specific mAbs, the outcome of the response can be tolerance. This form of tolerance is peripheral, Ag specific, and maintained lifelong, and is associated with the suppression of nontolerant cells by CD4 cells of the toleran t host. Here we demonstrate that the degree of suppression is dependen t on the number of suppressor cells. A neutralizing anti-IL-4 Ab was p artially able to inhibit suppression, indicating a role for IL-4 in th e regulation of Th1 rejection responses.