Influence of the lentiviral vectors-mediated mouse genetic engineering Treg after allogeneic bone marrow transplantation on graft-versus-hostdiseaseinmice

Abstract

Objective To explore the influence of the lentiviral vectors-mediated mouse genetic engineering regulatory T cells (Treg) infused after allogeneie bone marrow transplantation (allo-BMT)on graft-versus-host disease (GVHD) in mice.Methods Lentivirus-mediated expression of Forkhead box P3 (Foxp3) converted CD4~+ CD25~- T cells from Balb/c mice into engineered Tregs in vitro.An allo-BMT model of Balb/c→C57BL/6 mice was established.Mice were randomly assigned into four groups:(1) The recipients in engineering Treg group were injected with 5×10~6 donor bone marrow cells and 5×10~6 splenoeytes plus 5×10~6 genetic engineering Treg;(2)The recipients in transplantation control group were iniected with 5×10~6 donor bone marrow cells and 5×10~6 splenocytes;(3) The recipients in radiation group were injected with 0.2 ml RPMI 1640;(4)The recipients in empty vector control group were injected with 5×10~6 donor bone marrow cells and 5×10~6 splenocytas plus 5×10~6 empty vector transduced CD4~+ CD25~- T cells.Survival time,clinical GVHD Score or histopathological analysis(skin,liver and small intestine) were observed after allo-BMT.Chimerism of bone marrow cells from recipients survived for 60 days after transplantation was measured Results The mean survival times in radiation group, transplantation control group,erIgineering Treg group and empty vector control group were (8.8±0.6),(36.7±2.5),(51.6±4.0) and (34.1±2.3)days respectively.The survival time in engineering Treg group was signiticantly prolonged as compared with other groups as judged by the log-rank test(P<0.05).Histopathological ahalysis in several target organs (skin,liver and small intestine)confirmed the presence of severe GVHD in transplantation control group and empty vector control group. No histological signs of GVHD were observed in recipients in engineering Treg group and clinical GVHD scores in this group were significantly decreased compared to transplantation control group and empty vector control group. Conclusion Co-injection of genetic engineering Treg can efficiently prevent recipients from lethal GVHD during allo-BMT in mice Key words: Bone marrow transplantation; T-lymphocytes, regulatory; Graft vs host disease; Transgenes; Forkhead transcription factors