Project description:Cohort study of 137 renal transplant recipients and 29 non-immunosuppressed controls, looking at clinical influences upon monocytic HLA-DR density (mHLA-DRd) and associated clinical outcomes (namely, malignancy development)
Project description:HLA-DR-lacking HSPCs [HLA-DR(-) HSPCs] were detected in aplastic anemia (AA) patients with HLA-DR15. HLA-DR(-) HSPCs may evade the attack by CD4+ T-cells recognizing the autoantigen presented by HLA-DR15. The goal of this study is to clarify the immune escape mechanisms from antigen-specific T-cells by comparing the trranscriptome profile of HLA-DR(+) HSPCs and HLA-DR(-) HSPCs.
Project description:Myeloid-derived suppressor cells (MDSC) is a heterogeneous population of cells that can negatively regulate T-cell function. As opposed to murine MDSC, which are characterized as Gr-1+CD11b+ cells, human MDSC are not so clearly defined due to lack of specific markers. Our lab has previously identified a new subset of MDSC as CD14+HLA-DR-neg/low cells from PBMC. CD14+HLA-DR-neg/low MDSC not only suppress proliferation and IFN-gamma secretion of autologous T cells, but also induce CD25+Foxp3+ regulatory T cells that are suppressive in vitro, whereas the counterpart CD14+HLA-DR-high monocytes don’t have the effect. In this study, we compare the immune-related gene expression between CD14+HLA-DR-neg/low MDSC and CD14+HLA-DR-high monocytes to better characterize the difference between these two populations and to find new potential specific marker for human MDSC. PBMC were isolated from fresh blood healthy donor by density centrifugation. CD14+ cells were isolated by AutoMACS CD14 microbeads using a AutoMACS (Miltenyi), and then stained with CD14 and HLA-DR antibodies. MDSC and monocytes control cells were sorted as CD14+ HLA-DR-neg/low and CD14+HLA-DR-high cells respectively. The sorted two populations were immediately frozen in liquid nitrogen and shipped to the company on dry ice for RNA isolation and further microarray.
Project description:Myeloid-derived suppressor cells (MDSC) is a heterogeneous population of cells that can negatively regulate T-cell function. As opposed to murine MDSC, which are characterized as Gr-1+CD11b+ cells, human MDSC are not so clearly defined due to lack of specific markers. Our lab has previously identified a new subset of MDSC as CD14+HLA-DR-neg/low cells from PBMC. CD14+HLA-DR-neg/low MDSC not only suppress proliferation and IFN-gamma secretion of autologous T cells, but also induce CD25+Foxp3+ regulatory T cells that are suppressive in vitro, whereas the counterpart CD14+HLA-DR-high monocytes don’t have the effect. In this study, we compare the immune-related gene expression between CD14+HLA-DR-neg/low MDSC and CD14+HLA-DR-high monocytes to better characterize the difference between these two populations and to find new potential specific marker for human MDSC.
Project description:Comprehensive analysis of the complex nature of the Human Leukocyte Antigen (HLA) class II ligandome is of utmost importance to understand the basis for CD4+ T cell mediated immunity and tolerance. Here, we implemented important improvements in the analysis of the repertoire of HLA-DR-presented peptides, using hybrid mass spectrometry-based peptide fragmentation techniques on a ligandome sample isolated from matured human monocyte-derived dendritic cells (DC). The reported data set constitutes nearly 14 thousand unique high-confident peptides, i.e. the largest single inventory of human DC derived HLA-DR ligands to date. From a technical viewpoint the most prominent finding is that no single peptide fragmentation technique could elucidate the majority of HLA-DR ligands, due to the wide range of physical chemical properties displayed by the HLA-DR ligandome. Our in-depth profiling allowed us to reveal a strikingly modest correlation between the abundance levels of surface-presented peptides and the cellular expression of their source proteins. Important selective sieving from the sampled proteome to the ligandome, was evidenced by specificity in the sequences of the core regions both at their N- and C- termini, hence not only reflecting binding motifs but also dominant protease activity associated to the endolysosomal compartments. Moreover, we demonstrate that the HLA-DR ligandome reflects a surface representation of cell-compartments specific for biological events linked to the maturation of monocytes into antigen presenting cells. Our results present new perspectives into the complex nature of the HLA class II system and will aid future immunological studies in characterizing the full breadth of potential CD4+ T cell epitopes relevant in health and disease.
Project description:Immunosuppression is needed in HLA identical sibling renal transplantation. We conducted a tolerance trial in this patient cohort using Alemtuzumab induction, donor hematopoietic stem cells, tacrolimus/mycophenolate immunosuppression converted to sirolimus, planning complete drug withdrawal by 24 months post-transplantation. After an additional 12 months with no immunosuppression, normal biopsies and renal function, recipients were considered tolerant. Twenty recipients were enrolled. Of the first 10 (>36 months post-transplantation), 5 had immunosuppression successfully withdrawn for 16-36 months (tolerant), 2 had disease recurrence and 3 had subclinical rejection in protocol biopsies (non-tolerant). Microchimerism disappeared after 1 year, and CD4+CD25highCD127-FOXP3+ T cells and CD19+IgD/M+CD27- B cells increased to 5 years post-transplantation in both groups, whereas immune/inflammatory gene expression pathways in the peripheral blood and urine were differentially downregulated in tolerant compared to non-tolerant recipients. Therefore, in this HLA identical renal transplant tolerance trial, absent chimerism, Treg and Breg immunophenotypes were indistinguishable between tolerant and non-tolerant recipients, but global genomic changes indicating immunomodulation were observed only in tolerant recipients.