Lethal systemic graft-vs-host disease in neonatally tolerant, but not in F1 hybrid mice.

The possibility, conditions, and quantitative aspects of eliciting GVHD in CBA (H-2k) mice made neonatally tolerant to the alloantigens of the donor A (H-2a) strain were studied. The intravenous injection of different doses (10(7)-2 x 10(8)) of A spleen cells caused a severe, often fatal, systemic GVHD in 12-month-old tolerant mice. The GVHD was found to be specific: spleen cells of a third party strain (B10) did not induce any disease. The intensity and the mortality of the GVHD depended on the cell dose and on the age of the recipients. In contrast, unirradiated (CBA x A)F1 recipients proved to be resistant to the lethal disease. In spite of their different susceptibility to the systemic GVHD, the tolerant and F1 hybrid recipients showed equally strong local GVH reactivity in the popliteal lymph node enlargement assay. Neonatally tolerant mice offer a new, sensitive model for the induction of lethal GVHD without the need of immunosuppression or irradiation.