Project description:Mucosa-associated invariant T (MAIT) cells are unconventional innate-like T cells that recognize microbial riboflavin metabolites presented by the MHC class I-like protein MR1. Human MAIT cells predominantly express the CD8α co-receptor (CD8+), with a smaller subset lacking both CD4 and CD8 (DN). However, it is unclear if these two MAIT cell sub-populations distinguished by CD8α represent functionally distinct subsets. To address this, we investigated the phenotypic, transcriptional, and functional differences between CD8+ and DN MAIT cells using human samples from peripheral blood, mucosal tissues, and fetal tissues.
Project description:MAIT cells (MAITs) represent an abundant T lymphocyte subset with unique specificity for microbial metabolites presented by the MHC-1b molecule, MR1. MAIT conservation along evolution indicates important, non-redundant functions, but their low frequency in mice has hampered their detailed characterization. Here, we performed a transcriptomic analysis of murine MAITs in comparison with NKT subsets and with mainstream T cells in spleen and peripheral organs of B6-MAIT/CAST mice expressing a Rorc-GFP transgene. MAIT and NKT cells have been FACS-sorted after tetramer staining (MR1:5-OP-RU Tet+ for MAIT, CD1d:PBS57Tet+ for NKT), and 1/17 subsetting based on the expression of Rorc.
Project description:A recently identified unconventional T cell population known as mucosal-associated invariant T (MAIT) cells are characterized by the expression of semi-invariant T cell receptor (TCR) with a canonical TRAV1-2/TRAJ33 (Vα7.2/Jα33). These evolutionary conserved, innate-like T cells recognize vitamin B metabolites, derived from some bacteria and fungi. Due to their presence not only in the T cell repertoire of mucosal surfaces but also in peripheral blood and liver, and their significant involvement in a wide range of diseases, in-depth characterization of human MAIT cells is a timely requirement. Studies that examined the transcriptome, immunoproteome, and whole-cell proteome characterized the role of cytotoxic molecules and cytokines in effector functions of MAIT cells and their relationship with some other immune cell subsets. As MAIT cells are classified under the CD3+ T cell compartment and the majority express surface receptor CD8, identifying their proteomic relationship with CD3+ and CD8+ T cells is pivotal. Thus, a high-resolution dataset was generated using the cell populations sorted from peripheral blood mononuclear cells of three healthy volunteers to describe the whole cell proteomes of MAIT, CD3+, and CD8+ T cells. Trypsin-digested peptide samples obtained from the methanol co-precipitation method were analyzed using an Orbitrap FusionTM TribridTM mass spectrometer (Thermo Fisher Scientific, USA) inline coupled to nanoACQUITY ultra-performance liquid chromatography system (Waters, USA) to acquire data-dependent shotgun proteomic data (DDA-MS) for label-free quantification. Analysis of raw DDA-MS data using MaxQuant software and maxLFQ identified and quantified 4,442 protein groups at a 1% false discovery rate. Further analysis identified 3,680 proteins which were detected with a single UniProt accession and a minimum of 2 unique or razor peptides. Thus this proteomic dataset can be used as a reference proteome for future studies on human MAIT cells.
Project description:Human peripheral blood NK cell popiulations were seperated on the basis of CD56 expression with flowcytometry. Sorted CD56-bright (CD56Br) and CD56-dim (CD56Dim) NK cells were subjected to H3K4Me2 ChIPmentation to obtain epigenome profiles for downstream analyses.
Project description:A small subset of T cells also expresses kiler-cell immunoglobulin-like receptors (KIRs). We find that KIR+ T cells primarily reside in the CD56+ T population. However, little is known on how these cells are different from the conventional CD56- T, NK, and iNKT cells. We used microarray profiling to compare and determine the distinctive differences of CD56+ T cell and its KIR subsets when compared to the conventional CD56- T, NK and iNKT cells. Lymphocyte subsets were sorted from human peripheral blood mononuclear cells with FACSAriaII (BD Biosciences, San Jose, CA) using anti-CD3, anti-CD56, anti-CD14, anti-KIR2DL1, anti-KIR2DL2/3, anti-KIR3DL1 and anti-TCRValpha24 antibodies. The purity of CD3+CD56- T cells, CD3-CD56+ NK cells, CD3+CD56+ T cells, KIR-CD3+CD56+ T cells, and KIR+CD3+CD56+ T cells were more than 98% in all experiments. The purities of iNKT cells for TCRValpha24 and CD1d-tetramer were >95% and >90%, respectively. RNA pre-amplification, labeling and hybridization on Human Genome U133Plus 2.0 GeneChip array were performed in the St. Jude Hartwell Center for Bioinformatics & Biotechnology microarray core facility according to the manufacturer’s instructions (Affymetrix, Santa Clara, CA).
Project description:Mucosal-associated invariant T (MAIT) cells recognize bacterial metabolites as antigen and are found in blood and tissues, where they are poised to contribute to barrier immunity. Recent data demonstrate that MAIT cells located in mucosal barrier tissues are functionally distinct from their blood counterparts, but the relationship and circulation of MAIT cells between blood and different tissue compartments remains poorly understood. Previous studies raised the possibility that MAIT cells do not leave tissue and may either be retained or undergo apoptosis. To directly address if human MAIT cells exit tissues, we collected human donor-matched thoracic duct lymph and blood and analyzed MAIT cell phenotype, transcriptome and TCR diversity by RNAseq.
Project description:There is limited knowledge on the origin and development of the ample spectrum of human NK cells, particularly of specialized NK subsets. Here, we characterized the NK cell progeny of CD34+DNAM-1bright CXCR4+ precursors that reside in healthy bone marrow and circulate in the peripheral blood (PB) of patients with chronic infections/inflammation. including HIV, HCV or HCMV reactivation after HSC transplantation. Unlike conventional CD34+ precursors they rapidly differentiated in vitro into cytotoxic, IFNγ-secreting CD94/NKG2C+KIR+CD57+ maturing NK cell progenies with HCMV-inhibiting activity. Progeny characterization led also to identification of an additional new PB Lin-CD56-CD16+ precursor giving rise to the same CD94/NKG2C+KIR+CD57+ maturing NK cell progenies. Microarray analysis of NK cell progenies revealed a signature compatible with maturing adaptive NK cells. In vivo circulation of multiple common lymphocyte precursors with rapid development to NKG2C+ NK cell progeny is steadily occurring and may thus be a crucial resource for the prompt control of HCMV. We used microarray to compare the transcriptional profiles of human NKG2C+ NK cells derived from i) CD34+DNAM1brightCXCR4+ precursors, ii) Lin-CD34-CD16+CD56- precursors, iii) peripheral blood.