Genetic Factors Influencing Irradiation Protection by Bone Marrow. V. Multiple Allogeneic Donors

Summary

Under certain conditions, lethally irradiated strain A mice were protected against acute irradiation death by a marrow pool from several allogeneic donors without an increase of the total inoculum. The secondary disease syndrome was severe and lethal when the marrow pool consisted of only “incompatible” marrow. Addition of related hybrid marrow or H-2 “compatible” marrow to the pool decreased the severity of the syndrome. Survival was intermediate between that expected after the inoculation of the most compatible marrow and the least compatible marrow. Permanent marrow grafts, as indicated by acceptance of parental strain skin homografts and by presence of hybrid γ-globulin allotypes, were established with marrow from related F₁ hybrids and H-2 compatible hybrids. Permanent skin homografts indicated mixed chimerism between related F₁ hybrid and incompatible hybrid marrow when one parent of each hybrid was compatible. The γ-globulin allotype data suggest the possibility of other mixed chimerism, but absence of permanent skin homograft of the appropriate phenotype indicates the necessity for further investigation of the correlation of γ-globulin allotypes and skin homograft acceptance, or rejection, or both.