Identification of NM23-H2 as a tumour-associated antigen in chronic myeloid leukaemia.

Therapeutic effects of haematopoietic stem cell transplantation are not limited to maximal chemoradiotherapy and subsequent bone marrow regeneration, but include specific as well as unspecific immune reactions known as graft-versus-leukaemia (GvL) effects. Specific immune reactions are likely to be particularly relevant to the long-term treatment of diseases, such as chronic myeloid leukaemia (CML), in which residual cells may remain quiescent and unresponsive to cytotoxic and molecular therapies for long periods of time. Specific GvL effects result from the expression on leukaemic cells of specific tumour-associated antigens (TAAs) in the context of HLA proteins. As human leukocyte antigen…

An open-source computational and data resource to analyze digital maps of immunopeptidomes

We present a novel mass spectrometry-based high-throughput workflow and an open-source computational and data resource to reproducibly identify and quantify HLA-associated peptides. Collectively, the resources support the generation of HLA allele-specific peptide assay libraries consisting of consensus fragment ion spectra, and the analysis of quantitative digital maps of HLA peptidomes generated from a range of biological sources by SWATH mass spectrometry (MS). This study represents the first community-based effort to develop a robust platform for the reproducible and quantitative measurement of the entire repertoire of peptides presented by HLA molecules, an essential step towards the de…

Regulatory T Cells in an Endogenous Mouse Lymphoma Recognize Specific Antigen Peptides and Contribute to Immune Escape.

Abstract Foxp3+ regulatory T cells (Tregs) sustain immune homeostasis and may contribute to immune escape in malignant disease. As a prerequisite for developing immunologic approaches in cancer therapy, it is necessary to understand the ontogeny and the antigenic specificities of tumor-infiltrating Tregs. We addressed this question by using a λ-MYC transgenic mouse model of endogenously arising B-cell lymphoma, which mirrors key features of human Burkitt lymphoma. We show that Foxp3+ Tregs suppress antitumor responses in endogenous lymphoma. Ablation of Foxp3+ Tregs significantly delayed tumor development. The ratio of Treg to effector T cells was elevated in growing tumors, which could be …

Identification of α-tubulin as an autoantigen recognized by sera from patients with neuropsychiatric systemic lupus erythematosus.

In a previous study we found in 50% of patients with neuropsychiatric manifestations of systemic lupus erythematosus (NP-SLE) organ specific antibodies to 45-56 kD proteins in a 100,000 g supernatant (SN) from bovine brain mitochondria. Aim of the present study was to identify the corresponding target antigen. A 100,000 g SN from bovine brain mitochondria was applied to SDS-gel electrophoresis. A 50 kD band recognized by sera from patients with NP-SLE in the Western blot (WB) was excised from the gels and applied to mass spectrometry. The identified protein was expressed in Escherichia coli and retested against sera from eleven patients with NP-SLE (severe symptoms n=6, mild symptoms n=5), …

Transcutaneous Immunization with a Solid Nanoscopic Imiquimod Suspension Enhances Tumor Rejection

Abstract Introduction: Transcutaneous immunization (TCI) is a novel vaccination strategy to induce strong therapeutic cytotoxic T-lymphocyte (CTL) responses by directly targeting skin-resident professional antigen-presenting cells (APC). This vaccination approach is very promising to overcome current limitations of standard vaccination approaches that are mostly effective in prophylaxis, but not in the treatment of diseases. In this context, we have developed a TCI method based on a synthetic TLR7 agonist imiquimod that partial tumor protection in experimental rodent models. In our present work, we describe a novel optimized formulation of imiquimod in a solid suspension of crystalline imiq…

Author response: An open-source computational and data resource to analyze digital maps of immunopeptidomes

Exploring the MHC-peptide matrix of central tolerance in the human thymus

Ever since it was discovered that central tolerance to self is imposed on developing T cells in the thymus through their interaction with self-peptide major histocompatibility complexes on thymic antigen-presenting cells, immunologists have speculated about the nature of these peptides, particularly in humans. Here, to shed light on the so-far unknown human thymic peptide repertoire, we analyse peptides eluted from isolated thymic dendritic cells, dendritic cell-depleted antigen-presenting cells and whole thymus. Bioinformatic analysis of the 842 identified natural major histocompatibility complex I and II ligands reveals significant cross-talk between major histocompatibility complex-class…

Quantitative Analysis of Prion-Protein Degradation by Constitutive and Immuno-20S Proteasomes Indicates Differences Correlated with Disease Susceptibility

Abstract The main part of cytosolic protein degradation depends on the ubiquitin-proteasome system. Proteasomes degrade their substrates into small peptide fragments, some of which are translocated into the endoplasmatic reticulum and loaded onto MHC class I molecules, which are then transported to the cell surface for inspection by CTL. A reliable prediction of proteasomal cleavages in a given protein for the identification of CTL epitopes would benefit immensely from additional cleavage data for the training of prediction algorithms. To increase the knowledge about proteasomal specificity and to gain more insight into the relation of proteasomal activity and susceptibility to prion diseas…

Features of TAP-independent MHC class I ligands revealed by quantitative mass spectrometry.

TAP is responsible for transferring cytosolic peptides into the ER, where they can be loaded onto MHC molecules. Deletion of TAP results in a drastic reduction of MHC class I surface expression and alters the presented peptide pattern. This key molecule in antigen processing is tackled by several viruses and lost in some tumors, rendering the altered cells less vulnerable to T cell-based immune surveillance. Using the TAP-deficient cell line LCL721.174 and its TAP-expressing progenitor cell line LCL721.45, we identified and quantified more than 160 HLA ligands, 50 of which were presented TAP-independently. Peptides which were predominantly presented on the TAP-deficient LCL721.174 cell line…