OBJECTIVETo investigate the effects of immature dendritic cells (imDC) expressing chemokine receptor-7 (CCR7) on acute graft-versus-host disease (aGVHD) in allogeneic bone marrow transposed (allo-BMT) mouse model.

METHODSWe constructed the lentiviral vectors carrying mouse CCR7 gene and infect imDC effectively in vitro. GVHD model was established with C57BL/6(H-2b) donor mice and BALB/c (H-2d) recipient mice. After irradiation, recipients were injected with donor bone marrow and spleen cells along with CCR7-modified dendritic cells. Mice were randomized into irradiation, transplant control, pXZ9-imDC (empty vector control) and CCR7-imDC groups. Survival, GVHD score, histopathological analysis and plasma levels of inflammatory cytokines were observed.

RESULTSThe mean survival in irradiation, transplantation, pXZ9-imDC and CCR7-imDC groups were (8.20±1.48)d, (12.20±2.78)d, (20.70±6.01)d and (27.5±7.55)d respectively. The survival in CCR7- imDC group was significantly improved compared with other groups (P<0.05). GVHD scores in transplantation, pXZ9-imDC and CCR7-imDC groups were (6.90±1.66), (5.60±0.97) and (4.10±1.79) respectively. CCR7-imDC group had significantly lower GVHD score and minor tissue damages shown by histopathological analysis than the other groups. Plasma IFN-γ level increased and reached the peak at +10 day in transplant group, while it gradually decreased in pXZ9-imDC and CCR7-imDC groups, and then reached the nadir at +20 day post-allo-BMT, with the lowest level in CCR7-imDC group (P<0.01). Plasma IL-4 decreased in transplant group, while it gradually increased in pXZ9-imDC and CCR7-imDC groups and reached the highest level at + 10 day in CCR7- imDC group (P<0.01). The 95%-100% of H-2b positive cells in recipient mice on + 30 day post-allo-BMT demonstrated the complete donor- type implantation.

CONCLUSIONGenetically modified immature DC by CCR7 gene could alleviate damages by GVHD and prolong survival of recipient mice after allo-BMT.