[Effects of immature dendritic cells genetically modified to express sTNFR I on graft-versus-host disease (GVHD) and graft-versus-leukemia (GVL) in allogeneic bone marrow transplantation mice].
OBJECTIVE
To investigate the effect of immature dendritic cells (inDC) genetically modified to express sTNFR I on acute graft-versus-host disease (aGVHD) and the graft-versus-leukemia (GVL) effect ofter allogeneic bone marrow transplantation (allo-BMT) in leukemic mice and its mechanism.


METHODS
An EL4 leukemia allo-BMT model was established with the BALB/c (H-2d) donor mice (DM)and C57BL/6 (H-2b) recipient mice (RM). The RM received DM bone marrow (BM) cells at a 1:1 ratio with spleen cells intravenously via tail vein at 4 h after TBI. Fifty DM were separated randomly into five groups: (1) Group A: total body irradiation (TBI) group, (2) Group B: lymphoma cell leukemia group, (3) Group C: allo-BMT group, (4) Group D: pXZ9-DC group, (5) Group E: sTNFR I-DC group. Acute GVHD scores, incidence of leukemic cell infiltration, histopathological analysis, survival rate, and survival rate of the recipients were estimated after allo-BMT. Enzyme-linked immunosorbent assay (ELISA) method was used to detect cytokines (INF-gamma and IL-4 ) production. Flow cytometry (FCM) analysis was used to detect allogeneic chimerism.


RESULTS
(1) The mice in group A and group B all died of the BM failure and lymphoma cell leukemia, respectively. The mice in group C developed typical clinical signs of a GVHD after BMT with an average survival time(AST) of (11.50 +/- 3.50) d. The signs of aGVHD were less evident in the group D and E, and their AST (21.70 +/- 5.80 and 25.80 +/- 5.20 days, respectively) were all longer than that in group C (P < 0.05). AST of group E was the longest (P < 0.05). The mice in group B all died of leukemia within 18 days after engraftment of EL4 cells. There was was no significant difference in groups C, D and E in the incidence of leukemia (P > 0.05). (2) Serum IFN-gamma level reached peak value. At + 12 d, then decreased gradually in group C, D, and E, and then reached the nadir at +18 d post-BMT, with the lowest in group E (P < 0.05), and the level was significantly lower in group D than in group C (P < 0.05). After BMT, serum IL-4 level slightly decreased in group C, but gradually elevated in group D and E and reached their peak at +12 d, and even more significantly increased in group E (P < 0.05). There was no statistical significance in the pair wise comparison among three group (P < 0.05). (3) The average proportion of H-2d positive cells in RM was 95%-100% on day 30 post-BMT, with complete donor-type implantation.


CONCLUSIONS
Immature DC can induce immuno tolerance. Immature DC genetically modified to express sTNFR I has been shown to prevent acute GVHD in lethally irradiated mice reconstituted with allogeneic bone marrow grafts while maintaining the GVL response.
Department of Hematology, the Affiliated Hospital of Xuzhou Medical College, Xuzhou 221002, China.
Shu-Hua
SH
Wang
De-Peng
DP
Li
Yan-Jun
YJ
Zhang
Pu
P
Zhang
Ling-Yu
LY
Zeng
Xiu-Ying
XY
Pan
Kai-Lin
KL
Xu
Yi-Hong
YH
Huang
D000818:Animals; D016026:Bone Marrow Transplantation / Q000009:adverse effects / Q000379:methods*; D003713:Dendritic Cells / Q000276:immunology*; D005260:Female; D006086:Graft vs Host Disease / Q000517:prevention & control*; D020544:Graft vs Leukemia Effect; D007108:Immune Tolerance; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000235:genetics*; D014184:Transplantation, Homologous
D047888:Receptors, Tumor Necrosis Factor, Type I