The Role Of Th17Cell In Graft-vs-host Disease, And The Production And Certification Of Genetic Engineered Th17Cells

This research paper contains two independent parts. Part one was focused on therelationship between interleukin-17/Th17cells and Graft-vs-Host disease (GVHD) ina mouse allogenetic hematopoietic stem cell transplantation (allo-HSCT) model; andin part two, a novel method was explored to generate and purify genetic engineeredTh17cells.Th17cell is a newly identified CD4+T help cell subset, which secretspreinflammatory cytokines such as IL-17, and plays a crucial role in autoimmunediseases and host defence against microbial pathogens. However, the function ofTh17cell in GVHD is still controversial. In researchs belong part one, we establishedsever and mild to moderate mouse GVHD model via different dose of splenocytesinfusion. We found that the ratio of Th17cell and the concentration of IL-17inperipheral blood is negative correlation to the severity of GVHD. We further exploredthe relationship between CD4+T cell subsets imbalance and organ specific GVHD.We found Th1subset was positive correlated to liver GVHD, Th17subset waspositive correlated to lung GVHD, and Th1/Th17ratio is positive correlated to smallintestine GVHD. To elucidate the relationship of Th17cell and GVHD associatedlung injury, we have used lung-specific-overexpression IL-17transgenic mouse asallo-HSCT receipts. Using this model, we have approved that IL-17is contributed toGVHD associated lung injury after allo-HSCT. Besides, we identified the mechanismis IL-17can recruit inflammatory cell by up-regulating the transcription of many chemokins and can promote Th1cell differentiation in lung tissue.Currently, efficient production and purification of Th17cells remains extremelydifficult. There are several reasons for this difficulty:(1) Th17cells is a rare cellpopulation,(2) no specific cell surface marker or panel of surface markers have beenidentified to enable Th17cell isolation and (3) complexity of Th17development. Inpart two, we introduced a novel method to obtain highly-purified genetic engineeredTh17cells. We have combined over-expression of RORγt to TGF-β and IL-6treatment to get superior Th17production efficiency. Besides, we embedded IL-17promoter-derived truncated human nerve growth factor receptor (ΔNGFR) gene as atag to detect IL-17transcription and to sort Th17cells. We have approved that thesegenetic engineered Th17cells produced by over-expression of RORγt plus TGF-β andIL-6treatment was more similar to natural occurred Th17cells as compare to geneticengineered Th17which produced by over-expression of RORγt alone. This techniquemay provide a useful toll to explore the function of Th17cells.