Attempts to induce tolerance to maternal tissue by irradiation of fetal mice.

Abstract

Lengerova's work, which reported radioinduced tolerance in rats to maternal tissue by irradiation of embryonic rats with low doses of x rays, was repeated using mice with tissue incompatibilities between the mother and offspring and controlled by the H-2 locus. The pregnant mice were exposed to 200 r of x rays at 15? 1 days of gestation, and skin grafts from the maternal strain and other strains were applied to normal and irradiated hybrids at ages of 43 to 67 days, the grafts being examined daily for 30 days for evidence of a homograft reaction. There was no difference between the normal and irradiated mice in their rejection of unrelated strain grafts, and for maternal strain grafts the irradiated mice were found to reject their grafts a little earlier and to have a more severe reaction to the graft than the normal mice. Some of the differences between these experiments and those of Lengerovs are discussed, along with possible explanations of the disagreement. (D.L.C.)