Murine regulatory DCs induce T-cell anergy in human xenoreactive T cells.
(A) Cells were stained with the stated mAbs or isotype-matched mAbs, and cell surface expression was analyzed by FACS. Data are represented by a histogram in which cells were stained with the stated mAbs (thick lines) or isotype-matched mAbs (thin lines). The values shown in the flow cytometry profiles are MFI. The results are representative of 5 individual experiments with similar results. (B) SCID mice received transplants of unprimed human T cells (●), human T cells primed with murine normal DCs (▴), human T cells primed with murine regulatory DCs (▪), or human T cells primed with murine regulatory DCs plus human IL-2 at a T cell/DC ratio of 10:1 for 3 days (▾). Mice were monitored daily for survival. The results are representative of 2 individual experiments with similar results. P < .01 compared with hu-PBL-SCID mice by the Mann-Whitney U test). (C) Human T cells were obtained from the spleen in each group of hu-PBL-SCID mice on day 10 after xenogeneic transplantation. Isolated human T cells (105) were cultured with murine normal DCs (103 to 5 × 104), and the proliferative response was measured on day 5. Data were expressed as mean values ± SDs of 5 individual experiments. *P < .01 compared with human T cells plus murine normal DCs by Student pairedt test. (D) The hu-PBL-SCID mice were injected with or without murine regulatory DCs (4 × 106/mouse) 2 days following xenogeneic transplantation. Alternatively, intravenous injections of human IL-2 (104U/mouse) were performed on days 3, 5, and 7 following xenogeneic transplantation in hu-PBL-SCID mice receiving murine regulatory DCs. Mice were monitored daily for survival. The results are representative of 2 individual experiments with similar results. P < .01 compared with hu-PBL-SCID mice by the Mann-Whitney U test. (E) SCID mice received transplants of murine allogeneic BM cells plus spleen mononuclear cells. Subsequently, the recipients were injected with or without murine normal or regulatory DCs (4 × 106/mouse) 2 days following allogeneic transplantation. Mice were monitored daily for survival. The results are representative of 2 individual experiments with similar results. P < .01 compared with untreated SCID mice that did not receive transplants by the Mann-Whitney U test.
