Adjusting subsets of peripheral dendritic cells by granulocyte-colony stimulating factor to induce transplantation immunologic tolerance in mice

ObjectiveTo discuss the possibility of adjusting the ratio of two subsets of peripheral d endritic cells (DC), DC1 and DC2, by utilizing recombinant human granulocyte-co lony stimulating factor (rhG-CSF), to induce transplantation immunologic tolera nce in mice.Methods BALB/c mice were subcutaneously injected with rhG-CSF 10 μg/day for 6 days, an d DC1/DC2 were examined. Then C57BL/6 mice PBMC 2×10 6 were injected into thes e mice. After 7 days, the peripheral DC and T lymphocyte were separated and exam ination of Th1/Th2 cytokines secretion, capacity of DC pulsed T cell proliferati on, mixed lymphocyte reaction (MLR) and mouse heart transplantation were perform ed.ResultsIn mice receiving rhG-CSF, the number of the peripheral DC2 was increased from ( 9.6 ± 2.6 )×10 6/L to ( 45.4 ± 9.9 )×10 6/L (P 0.01 ), bu t the number of DC1 did not change, ratio of DC1/DC2 was inverted. The capacity of DC pulsed T cell proliferation separated from these mice did not change compa red with normal mice. Cytokine secreting profile inclined to Th2 style. And the MLR intensity was reduced significantly in mice receiving G-CSF and allo-lymph ocyte pulsing (P 0.01 ). The heart allograft survival time was prolonged [( 7.2 ± 1.5 ) days vs ( 17.7 ± 4.3 ) days, P 0.01 ].ConclusionG-CSF can invert the ratio of DC1/DC2 by increasing the number of the periphera l DC2, but having no effect on DC1. And it can predominantly introduce Th2 immun ologic response to allo-antigen, and can induce transplantation immunologic tol erance.