X-RAY-INDUCED CHROMOSOMAL-ABERRATIONS AND CELL-KILLING IN SOMATIC ANDGERM-CELLS OF THE SCID MOUSE

To characterize further the radiosensitivity of severe combined immuno deficiency (scid) mice, the induction of micronuclei (MN) in polychrom atic erythrocytes as well as cell killing and translocation induction in stem cell spermatogonia was studied. Scid mice turned out to be cle arly hypersensitive for X-ray-induced cell killing of both bonemarrow cells and spermatogonial stem cells. The frequencies of recorded micro nuclei in polychromatic erythrocytes were comparable with that reporte d for the normal mouse, whereas the recovery of translocations was ext remely low in the scid mouse. The dos-response relationship for induce d translocations was bell shaped with a maximum of about 0.5% around d oses of 0.5-1.5 Gy X-rays.