Cutting edge: unconventional CD8+ T cell recognition of a naturally occurring HLA-A*02:01-restricted 20mer epitope

Unconventional HLA class I-restricted CD8+ T cell epitopes, longer than 10 aa, have been implicated to play a role in human immunity against viruses and cancer. T cell recognition of long peptides, centrally bulging from the HLA cleft, has been described previously. Alternatively, long peptides can contain a linear HLA-bound core peptide, with a N- or C-terminal peptide "tail" extending from the HLA peptide binding groove. The role of such a peptide "tail" in CD8+ T cell recognition remains unclear. In this study, we identified a 20mer peptide (FLPTPEELGLLGPPRPQVLA [FLP]) derived from the IL-27R subunit α gene restricted to HLA-A*02:01, for which we solved the crystal structure and demonstrated a long C-terminal "tail" extension. FLP-specific T cell clones demonstrated various recognition modes, some T cells recognized the FLP core peptide, while for other T cells the peptide tail was essential for recognition. These results demonstrate a crucial role for a C-terminal peptide tail in immunogenicity. </p

Broadly applicable TCR-based therapy for multiple myeloma targeting the immunoglobulin J chain

Background: The immunoglobulin J chain (Jchain) is highly expressed in the majority of multiple myeloma (MM), and Jchain-derived peptides presented in HLA molecules may be suitable antigens for T-cell therapy of MM. Methods: Using immunopeptidomics, we identified Jchain-derived epitopes presented by MM cells, and pHLA tetramer technology was used to isolate Jchain-specific T-cell clones. Results: We identified T cells specific for Jchain peptides presented in HLA-A1, -A24, -A3, and -A11 that recognized and lysed JCHAIN-positive MM cells. TCRs of the most promising T-cell clones were sequenced, cloned into retroviral vectors, and transferred to CD8 T cells. Jchain TCR T cells recognized target cells when JCHAIN and the appropriate HLA restriction alleles were expressed, while JCHAIN or HLA-negative cells, including healthy subsets, were not recognized. Patient-derived JCHAIN-positive MM samples were also lysed by Jchain TCR T cells. In a preclinical in vivo model for established MM, Jchain-A1, -A24, -A3, and -A11 TCR T cells strongly eradicated MM cells, which resulted in 100-fold lower tumor burden in Jchain TCR versus control-treated mice. Conclusions: We identified TCRs targeting Jchain-derived peptides presented in four common HLA alleles. All four TCRs demonstrated potent preclinical anti-myeloma activity, encouraging further preclinical testing and ultimately clinical development.Proteomic

A toddler with an itchy, brown rash

Dermatology-oncolog

Cutaneous Anaplastic Large Cell Lymphoma and Peripheral T-Cell Lymphoma NOS Show Distinct Chromosomal Alterations and Differential Expression of Chemokine Receptors and Apoptosis Regulators

Primary cutaneous anaplastic large cell lymphoma (C-ALCL) has an indolent clinical course and favorable prognosis. On the contrary, primary cutaneous peripheral T-cell lymphoma not otherwise specified (PTL-NOS) shows aggressive clinical behavior. To identify genomic events relevant in the pathogenesis of these cutaneous T-cell lymphomas (CTCLs), we carried out array-based comparative genomic hybridization (CGH) analysis. Simultaneously, gene expression profiling was conducted to gain insight into gene expression programs associated with the different clinical behavior of these CTCLs. C-ALCL was characterized by gains on chromosome 7q and 17q and losses on 6q and 13q. PTL-NOS similarly showed gains on 7q and 17q, but was distinguished by gains on chromosome 8 and loss of a focal overlapping region on 9p21. We identified minimal common regions harboring candidate oncogenes and tumor suppressor genes in C-ALCL and PTL-NOS. Genes with a role in lymphocyte chemotaxis, apoptosis, and proliferation were overrepresented among genes differentially expressed between these lymphomas. C-ALCL showed higher expression of the skin-homing chemokine receptor genes CCR10 and CCR8, which may explain the lower tendency to disseminate to extracutaneous sites. Furthermore, C-ALCL and PTL-NOS showed aberrant expression of distinct genes implicated in apoptosis and proliferation, such as IRF4/MUM1 and PRKCQ, which may account for differences in clinical aggressiveness.Dermatology-oncolog

microRNA deep sequencing in Sezary Syndrome reveals upregulation of miR-199a2/miR-214 cluster derived from the DNM3os transcript

Dermatology-oncolog

MicroRNA-21 Expression in CD4+T Cells Is Regulated by STAT3 and Is Pathologically Involved in Sezary Syndrome

Dermatology-oncolog

A meta-analysis of gene expression data identifies a molecular signature characteristic for tumor-stage mycosis fungoides

Mycosis fungoides (MF) is the most common type of primary cutaneous T-cell lymphoma (CTCL). To identify a molecular signature characteristic of MF tumor stage, we used a bioinformatic approach involving meta-analysis of publicly available gene expression data sets combined with previously generated gene expression data. Results for a selection of genes were further refined and validated by quantitative PCR and inclusion of additional controls. With this approach, we identified a profile specific for MF tumor stage, consisting of 989 aberrantly expressed genes, the majority of which (718 genes) are statistically significantly more expressed in MF compared with normal skin, inflamed skin, and normal T cells. As expected, the signature contains genes reflecting the highly proliferative characteristic of this T-cell malignancy, including altered expression of cell cycle and kinetochore regulators. We uncovered details of the immunophenotype, suggesting that MF originates from IL-32-producing cells and identified previously unreported therapeutic targets and/or diagnostic markers, for example, GTSF1 and TRIP13. Loss of expression of the NF-κB inhibitor, NFKBIZ, may partly explain the enhanced activity of NF-κB, which is a hallmark of MF and other CTCLs.Molecular tumour pathology - and tumour genetic

miRNA expression profiling of mycosis fungoides

MicroRNAs (miRNAs) are small RNA species that regulate gene expression post-transcriptionally and are aberrantly expressed in many malignancies including lymphoma. However, the role of miRNAs in the pathogenesis of T-cell lymphoid malignancies is poorly understood. Previously we examined the miRNA profile of Sézary syndrome (Sz), a leukemia of skin-homing memory T cells. In this study we determined the complete miRNome of mycosis fungoides (MF), the most common type of cutaneous T cell lymphoma. The miRNA profile of skin biopsies from 19 patients with tumor stage MF and 12 patients with benign inflammatory dermatoses (eczema and lichen planus) were compared by microarray analysis. We identified 49 miRNAs that are differentially expressed in tumor stage MF compared to benign inflammatory dermatoses using ANOVA analysis (P < 0.05, Benjamini-Hochberg corrected). The majority of the differentially expressed miRNAs (30/49) were up-regulated in tumor stage MF. The most significant differentially expressed were miR-155 and miR-92a (both up-regulated in tumor stage MF), while miR-93 showed the highest up-regulation in tumor stage MF with a fold difference of 5.8. Differential expression of a selection of these miRNAs was validated by miRNA-Q-PCR on additional test groups (tumors and controls). None of the miRNAs up-regulated in tumor stage MF was previously shown to be up-regulated in Sz, and only 2 of the 19 miRNAs down-regulated in tumor stage MF were also down-regulated in Sz. Taken together this report is the first describing the miRNA signature of tumor stage MF.Dermatology-oncolog