The induction of immunologic tolerance in newborn mice by spleen cells differing in H-2K or H-2D, but not "I-J," genotype.

Newborn mice of various strains belonging to the B10A series of recombinants received injections of spleen cells from adult donors to induce immunologic tolerance to antigens of the major histocompatibility complex (MHC). Donor-host combinations were chosen so as to provide differences at H-2K or H-2D, together with various portions of the Ia region. The experiments were predicated on the hypothesis that differences at "I-J" might be required for activation of suppressor cells--thus for the induction of the tolerant state. Tolerance was assessed both by skin grafting and by enumeration of antiallogeneic cytotoxic T lymphocyte precursors (CTL-P) through in vitro limiting-dilution cloning analysis. Host mice that differed from the donor strain only at H-2D, or at H-2K and H-2I-A, were rendered tolerant just as readily as those that differed at "I-J" plus H-2D or "I-J" plus H-2K and H-2I-A. The hypothesis that "I-J" differences are essential for tolerance induction was thus clearly negated.