| Abstract: | The effect of abolition of hybrid resistance by injection of lymphocytes on survival of lethally irradiated mice protected by transplantation of semiallogeneic bone marrow was studied. Injection of C57BL lymphocytes into (C57BL×CBA)F1 recipients 1 day before irradiation and transplantation of bone marrow of the same genotype (C57BL) increased the survival rate of the chimeras compared with untreated recipients, whereas the same treatment, given 7 days before irradiation, reduced the survival rate of the chimeras. Injection of lymphocytes of the parental line had a negligible action on the radioresistance both of the hematopoietic stem cells (as shown by the endocolonization test) and on the body as a whole (as shown by the 30-day survival test) of the F1 hybrid; it is accordingly concluded that differences in the effectiveness of the splenocytes when injected at different times before irradiation cannot be explained by changes in radioresistance.Laboratory of Bone Marrow Culture and Transplantation, Central Institute of Hematology and Blood Transfusion, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR N. A. Fedorv.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 83, No. 1, pp. 42–44, January, 1977. |
