Haploidentical bone marrow cell reconstruction of tumor-bearing murine host

Abstract

Objective To investigate the roles of chimerism level after haploidentical bone marrow cell transplantation on graft versus tumor effect (GVT). Methods Thirty BALB/C mice were randomly divided into 3 groups: control group (group C, 10), mixed chimerism group (group A, 10), full donor chimerism group (group B, 10). Five BALB/C mice in group C were only inoculated with Renca cells (2.6 × 106). Ten mice in group A were conditioned with 4 Gy irradiation, followed by infusion by bone marrow cells of CB6F1 mice on the day 1, then inoculated with Renca cells (2. 6 × 106 ) on the day 8. Ten mice in group B were conditioned with 8 Gy irradiation, followed by infusion by bone marrow cells (5 ×106 ) of CB6F1 mice on the day 1, then inoculated with Renca cells ( 2. 6 × 106 ) on the day 8. Tumor growth was monitored every 4 day. In groups A and B, all mice were analyzed by FACScan cytometry on the day 14, 21 and 28 after BMT. Mice were killed at the 32nd day after inoculation with tumor cells and blood of all mice was collected. All tumors were taken out to be weighed. Results The results of chimera showed that engraftments in group A remained mixed donor chimerism and unstable, tended to decrease after 14 days. In group B, full donor chimerism developed, and the chimerism of engraftments remained above 90% and was preserved even after 28 days; The size and tumor growth rate in groups B were reduced as compared with groups A and C (P ＜0. 01 ). The tumor inhibitory rate in groups B was 52%. Conclusion Stable full donor chimerism status after haploidentical allogeneic bone marrow cell transplant is the basis of GVT. Key words: Bone marrow; Cell transplantation; Graft-versus-tumor effect; Chimerism