Immature Dendritic Cells Induce Immune Tolerance Of Mice Allogenic Tooth Transplantation

The aim of this study was to inhibit the rejection of mice allogenic tooth transplantation using the property of immature dendritic cells which induced transplantation immune tolerance.The mice allogenic tooth transplantation models and autogeneic tooth transplantation models were established, donor bone marrow-derived imDCs were injected to recipient mice by tail vein or regional skin respectively. The effect of inducing transplantation immune tolerance was observated by HE stain and immunohistochemistry. The results were compared with group of allogenic tooth transplantation without any treatment and group of autogeneic tooth transplantation. The whole research consisted of two parts as follow:Part 1 Generation of immature dendritic cells with different dose of granulocyte-macrophage colony-stimulating factor.Objective To demonstrate the effect of cytokine with different concentration on mice bone marrow-derived immature DCs and find the optimal cytokine dose for imDCs culture. Methods Mice bone marrow-derived immature DCs were cultured in the presence of low, moderate and high dose of GM-CSF with or without IL-4. The morphology of cells were observed and the phenotypes were detected. Results On day 7, DCs in low dose group had the least quantity, small synapses and low expression of CD80, CD86 and MHC class II. Both the quantity of DCs and the expression of CD80, CD86 and MHC class II increased when cultured with IL-4; the quantity of DCs in moderate dose group and high dose group were more higher than that in low dose group, synapses were more obvious, the expression of CD80, CD86 and MHC class II were higher, but the difference between the two groups was not obvious. There was also no difference of the quantity and maturity of DCs between the moderate dose group and high dose group whether cultured with IL-4 or not. Conclusion Higher purity of immature DCs could be gained when cultured with low dose of GM-CSF but the quantity was little. When the dose of GM-CSF was moderate or high, the quantity of DCs could increase, but it would be the mixture of mature DCs and immature DCs. IL-4 could increase the quantity and promote the maturation of DCs only when the dose of GM-CSF was low. It was no difference of yield and purity of immature DCs in moderate and high GM-CSF group whether combine IL-4 or not. Part 2 Effect of immature dendritic cells on rejection of mouse allogenic tooth transplantationObjective To investigate suppression effects of donor bone marrow-derived imDCs on the rejection of mice allogenic tooth transplantation. Methods The models of mice allogenic tooth ectopia transplantation and autogeneic tooth ectopia transplantation were established, mice bone marrow-derived imDCs generated with 50U/ml GM-CSF were injected to recipient 2*106/ mouse by two ways: one was tail vein 7 days before transplantation, the other was regional skin at day 0th and day 3th after transplantation. The two groups were compared with the group of autogeneic tooth transplantation and the group of allogenic tooth transplantation without any treatment. The suppression effects of imDCs on mice allogenic teeth rejection were observed through histopathology and immunohistochemistry. Results There was no obvious rejection in group of autogeneic tooth transplantation, but obvious rejection was occurred in group of allogenic tooth transplantation without any treatment and the appearance was that the skin in transplanted area presented prunosus, auricle swelling, skin temperature raised and the tissue surrounded tooth flaccidly,considerable lymphocyte infiltrated, hyperemia and hemorrhage; the group of injecting imDC by tail vein presented slight rejection, the appearance was hyperemia, red incrustation and hyalin exudate in transplanted area, the skin temperature slightly raised than opposite side, the tissue surrounded tooth not very tightly,neutrophilic leukocyte and partial lymphocyte infiltrated, hyperemia and hemorrhage, some area had cell degeneration; the appearance of group of injecting imDC by regional skin was similar with the group of allogenic tooth transplantation without any treatment. The semiquantitative analysis of immunohistochemistry showed that the positive rate of CD4+T cells and CD8+T cells in group of autogeneic tooth transplantation was the lowest in all experiment group; the positive rate of CD4+T cells and CD8+T cells in group of injecting imDCs by tail vein degraded obviously compared with the group of injecting imDCs by regional skin and the group of allogenic tooth transplantation without any treatment, but there was no difference of the positive rate of CD4+T cells and CD8+T cells between the last two groups. Conclusion It can lessen the rejection of allogenic tooth transplantation that injected donor bone marrow-derived imDCs by tail vein 7 days before transplantation, but the rejection can't be eliminated totally. Nevertheless, there was no obvious suppression effects on allogenic tooth transplantation that injected donor bone marrow-derived imDCs by regional skin.