Adoptive Transfer of Immunologic Tolerance into Normal Mice

Preimmunization tolerance induced by injecting mice with moderate quantities of purified protein antigens in saline and preventing later attempted induction of delayed hypersensitivity by injection of these antigens in Freund9s adjuvant could be broken by adoptive transfer of spleen cells from sensitized donors but not by cells from normal donors, could be transferred passively with serum immunoglobulin concentrate, and could be transferred adoptively with spleen cells from tolerant donors. Thus, it appears to be due to the manufacture and presence in tolerant mice of a hypersensitization-inhibiting antibody rather than to loss or blockade of a clone of potentially responsive immunocytes.