[Kinetic study of splenocytes after allogeneic murine bone marrow transplantation]

The study was purposed to understand immunological reconstitution of peripheral immune organs after transplantation, through establishing allogeneic murine bone marrow transplantation model and detecting the kinetic change of splenocytes after transplantation. C57BL/6 mice were donors, BALB/c mice were recipients. Recipient mice were divided into irradiation group (R), irradiation plus inoculating bone marrow mononuclear cells (MNC) group (B), and irradiation plus inoculating bone marrow mononuclear cells and spleno-MNC group (S). After transplantation, the mice were examined daily for the symptoms such as weight, hunched posture, activity, ruffled fur, diarrhea, and survival. Blood routine test was done once a week, splenocyte was counted and CD3, CD4, CD8, B220, CD11c positive cell relative count was detected by FACS on day 2, 7, 14, 27, 60 after transplantation, Liver, skin and intestine were biopsied for histopathological examination before dying. The results indicated that 89% mice in S group died of acute graft-versus-host disease (aGVHD) during day 6 to 78. The spleno-mononuclear cell count quickly decreased and reached to lowest level on day 2, then gradually recovered to level of pretransplantation on day 14; CD8 and B220 positive cells decreased to lowest level on day 12, in which CD8(+) cells quickly recovered and reached to level of pretransplantation, but the B220(+) recovered most slowly and sustained to be with low level, then gradually recovered to level of pretransplantation on day 60; CD3 and CD4 positive cells decreased relatively slowly, and reached to lowest level on day 14, then both gradually recovered to level of pretransplantation on day 60; CD11c positive cell count changed unstrikingly except day 14. It is concluded that when C57BL/6 mice are donors, and BALB/c mice are recipients treated with irradiation of 7.5 Gy and inoculated with 1 x 10⁷ bone marrow MNC and 1 x 10⁷ spleno-MNC, allogeneic murine bone marrow transplantation model can be thus set up. The spleno-mononuclear cells show obviously kinetic changes after transplantation, that CD8 positive cells recover ahead of all, then followed by CD3 and CD4 positive cells, and the reconstitution of B220 positive cells is the slowest.