Induced Tolerance and "Homologous Disease'"in X-Irradiated Mice Protected with Homologous Bone Marrow.

CBA mice protected against an otherwise lethal dose of irradiation with isologous CBA bone marrow showed normal rejection of skin grafts from the Cb strain. Irradiated CBA mice protected with Cb or (Cb x CBA) F1 hybrid marrow were tolerant of skin grafts from the Cb strain. Irradiated CBA mice protected with a mixture of marrow from the Cb and CBA strain were not tolerant of skin grafts from the Cb strain. Late mortality (21 to 60 days post-irradiation), after good early protection (21 days) against doses of whole body X-irradiation above the LD100, did not occur in mice protected with isologous bone marrow (where neither the host nor the donor can react immunologically against each other). It occurred in mice protected with homologous marrow from a foreign strain (where both the host strain and the donor strain can potentially react immunologically against each other). It did not occur in mice protected with marrow from an F, hybrid of the irradiated strain (where the host strain can potentially react against the donor strain but the donor strain has no potential to react against the host strain). It occurred in some but not all combinations of irradiated F1 hybrids protected with marrow from a parent strain (where the host has no potential to react against the donor strain but the donor strain can potentially react against the recipient strain).