Project description:Birdshot Uveitis (BU) is a blinding inflammatory eye condition that only affects HLA-A29-positive individuals. Genetic association studies linked ERAP2 with BU, an aminopeptidase which trims peptides before their presentation by HLA class I at the cell surface, which suggests that ERAP2-dependent peptide presentation by HLA-A29 drives the pathogenesis of BU. However, it remains poorly understood whether the effects of ERAP2 on the HLA-A29 peptidome are distinct from its effect on other HLA allotypes. To address this, we focused on the effects of ERAP2 on the immunopeptidome in patientderived antigen presenting cells. Using complementary HLA-A29-based and pan-class I immunopurifications, isotope-labeled naturally processed and presented HLA-bound peptides were sequenced by mass spectrometry. We show that the effects of ERAP2 on the N-terminus of ligands of HLA-A29 are shared across endogenous HLA allotypes, but discover and replicate that one peptide motif generated in the presence of ERAP2 is specifically bound by HLA-A29. This motif can be found in the amino acid sequence of putative autoantigens. We further show evidence for internal sequence specificity for ERAP2 imprinted in the immunopeptidome. These results reveal that ERAP2 can generate an HLA-A29-specific antigen repertoire, which supports that antigen presentation is a key disease pathway in BU.
Project description:Defining viral proteomes is crucial to understanding viral life cycles and immune recognition but the landscape of translated regions remains unknown for most viruses. We have developed massively parallel ribosome profiling (MPRP) to determine open reading frames (ORFs) across tens of thousands of designed oligonucleotides. MPRP identified 4208 unannotated ORFs in 679 human-associated viral genomes. We found viral peptides originating from detected noncanonical ORFs presented on class-I human leukocyte antigen (HLA-I) in infected cells and hundreds of upstream ORFs that likely modulate translation initiation of viral proteins. The discovery of viral ORFs across a wide range of viral families—including highly pathogenic viruses—expands the repertoire of vaccine targets and reveals potential cis-regulatory sequences.
Project description:HLA Class I antigen processing and presentation (APP) is a highly regulated process that enables CD8+ T cell immunosurveillance. APP begins with the ribosomal synthesis of a source antigen, yet the role of ribosomes, particularly specialized ribosomes, in antigen presentation is poorly understood. Here, we show that the presence of the “P-stalk” on the ribosome enhances antigen presentation. The addition of the P-stalk to the ribosome is stimulated by cytokines that upregulate APP components, and knockdown of one of the P-stalk proteins (P1) reduces T cell recognition of tumor cells. Mechanistically, we show that P1-containing ribosomes exhibit enhanced translation of HLA Class I molecules and accessory APP components. Finally, analysis of patient data reveals that the mRNA expression of the P-stalk proteins positively correlates with CD8+ T cell infiltration, a trend not seen for other ribosomal proteins. In all, we demonstrate that the presence of the P-stalk defines a specialized ribosome population that enhances antigen presentation, something that may be exploited by cancer cells to escape immunosurveillance.
Project description:Analysis of the immunopeptidome of Human Leukocyte Antigen (HLA)-A*11:01 during influenza infection. Analyses were performed using the Class I reduced C1R cell line transfected with the HLA class I allele HLA-A*11:01.
Project description:Gene expression analysis of molecules with known function in HLA class II antigen processing and presentation. Various hematopoietic cell types and (cytokine pre-treated) non-hematopoietic cells that are targeted in Graft-versus-Leukemia reactivity and Graft-versus-Host Disease were collected. Expression was compared between the different hematopoietic and non-hematopoietic cell types for the Invariant chain, HLA-DMA, HLA-DMB, HLA-DOA and HLA-DOB genes. The data show that the Invariant chain, HLA-DMA, HLA-DMB and HLA-DOA genes are expressed in all or the majority of cell types with HLA class II surface expression, whereas expression of the HLA-DOB gene is restricted to professional antigen presenting B-cells and mature dendritic cells. Total RNA was isolated from various hematopoietic cell types isolated (and cultured) from (G-CSF mobilized) peripheral blood from five different individuals and from (IFN-g pre-treated) fibroblasts cultured from skin biopsies from four different patients transplanted with allogeneic hematopoietic stem cells.
Project description:Synthetic long peptides (SLPs) are a promising vaccine modality that exploit dendritic cells (DC) to treat chronic infections or cancer. Currently, the design of SLPs relies on in silico prediction and multifactorial T cells assays to determine which SLPs are best cross-presented on DC human leukocyte antigen class I (HLA-I). Furthermore, it is unknown how TLR ligand-based adjuvants affect DC cross-presentation. Here, we generated a unique, high-quality immunopeptidome dataset of human DCs pulsed with 12 hepatitis B virus (HBV)-based SLPs combined with either a TLR1/2 (Amplivant®) or TLR3 (PolyI:C) ligand. The obtained immunopeptidome reflected adjuvant-induced differences, but no differences in cross-presentation of SLPs. We uncovered dominant (cross-)presentation on B-alleles, and identified 33 unique SLP-derived HLA-I peptides, several of which were not in silico predicted and some were consistently found across donors. Our work puts forward DC immunopeptidomics as a valuable tool for therapeutic vaccine design.
2025-01-19 | PXD051490 | Pride
Project description:Birinapant reshapes tumor immunopeptidome and enhances antigen presentation
Project description:Persistent therapy-resistant leukemia progenitor cells (LPC) are a main cause of disease relapse and recurrence in acute myeloid leukemia (AML). Specific LPC-targeting therapies may thus improve treatment outcome of AML patients. We demonstrated that LPCs present human leukocyte antigen (HLA)-restricted cancer antigens that induce T cell responses allowing for immune surveillance of AML. Using a mass spectrometry-based immunopeptidomics approach, we characterized the antigenic landscape of patient LPCs and identified AML/LPC-associated HLA-presented antigens including mutation-derived and cryptic neoepitopes as prime targets for development of T cell-based immunotherapeutic approaches. We observed frequent spontaneous memory T cells targeting these AML/LPC-associated antigens in AML patients and showed that antigen-specific T cell recognition and HLA class II immunopeptidome diversity impacts clinical outcome. Our results pave the way for implementation of AML/LPC-associated antigens for T cell-based immunotherapeutic approaches to specifically target and eliminate residual LPCs in AML patients.