ERAP1 shapes just part of the immunopeptidome

ERAP1 is an aminopeptidase involved in trimming long peptides to the lengths required for presentation by MHC class I. ERAP1 substrate preference is for peptides with hydrophobic or aliphatic N-terminal amino acids, with lower efficacy with charged and small hydrophilic amino acids and almost complete inefficiency with proline. Since ERAP1 efficiently trims peptides to eight amino acids or even shorter, and many MHC-I allotypes can only bind peptides that are eight or nine amino acids or longer, ERAP1 both produces and destroys potential ligands of these alleles. The observation that ERAP1 modulates the levels of presentation for only a subset of the immunopeptidome conflicts with the common assumption that most MHC-I peptides are derived from longer peptides that are produced by the proteasome, transported into the endoplasmic reticulum (ER) by the Transporter Associated Peptide Presentation (TAP) and then trimmed by ERAP1. A more likely mechanism is that cellular protein degradation produces surplus amounts of peptides that fit perfectly and are rapidly loaded onto the MHC, with only a minority of peptides requiring trimming within the ER before loading. Alternatively, ERAP1 may not be present in all ER compartments or vesicles where peptide processing and loading take place and thus affects just a subset of the immunopeptidome.     

High‐resolution analysis of the murine MHC class II immunopeptidome

The reliable identification of peptides bound to major histocompatibility complex (MHC) class II is fundamental for the study of the host immune response against pathogens and the pathogenesis of autoimmune conditions. Here, we describe an improved methodology combining immuno‐affinity enrichment of MHC class II complexes, optimized elution conditions and quadrupole Orbitrap mass spectrometry‐based characterization of the immunopeptidome. The methodology allowed the identification of over 1000 peptides with 1% false discovery rate from 10⁸ murine A20 lymphoma cells. The study revealed the I‐A^d‐specific motif in high resolution after multisequence alignment. The methodology was generally applied to the purification of MHC class II from cell lines and murine spleens. We identified 2963 peptides from BALB/c and 2712 from C57BL/6 mouse spleens. The identification of peptides bound to MHC class II in vitro and in vivo will facilitate the characterization of T‐cell specificities, as well as the development of biotherapeutics and vaccines.     

Prediction of cancer neoepitopes needs new rules

Tumors are immunogenic and the non-synonymous point mutations harbored by tumors are a source of their immunogenicity. Immunologists have long been enamored by the idea of synthetic peptides corresponding to mutated epitopes (neoepitopes) as specific “vaccines” against tumors presenting those neoepitopes in context of MHC I. Tumors may harbor hundreds of point mutations and it would require effective prediction algorithms to identify candidate neoepitopes capable of eliciting potent tumor-specific CD8⁺ T cell responses. Our current understanding of MHC I-restricted epitopes come from the observance of CD8⁺ T cell responses against viral (vaccinia, lymphocytic choriomeningitis etc.) and model (chicken ovalbumin, hen egg lysozyme etc.) antigens. Measurable CD8⁺ T cell responses elicited by model or viral antigens are always directed against epitopes possessing strong binding affinity for the restricting MHC I alleles. Immense collective effort to develop methodologies combining genomic sequencing, bioinformatics and traditional immunological techniques to identify neoepitopes with strong binding affinity to MHC I has only yielded inaccurate prediction algorithms. Additionally, new evidence has emerged suggesting that neoepitopes, which unlike the epitopes of viral or model antigens have closely resembling wild-type counterparts, may not necessarily demonstrate strong affinity to MHC I. Our bearing need recalibration.     

Exploiting the curative potential of adoptive T-cell therapy for cancer

Adoptive T-cell therapy (ACT) is a potent and flexible cancer treatment modality that can induce complete, durable regression of certain human malignancies. Long-term follow-up of patients receiving tumor-infiltrating lymphocytes (TILs) for metastatic melanoma reveals a substantial subset that experienced complete, lasting tumor regression – and may be cured. Increasing evidence points to mutated gene products as the primary immunological targets of TILs from melanomas. Recent technological advances permit rapid identification of the neoepitopes resulting from these somatic gene mutations and of T cells with reactivity against these targets. Isolation and adoptive transfer of these T cells may improve TIL therapy for melanoma and permit its broader application to non-melanoma tumors. Extension of ACT to other malignancies may also be possible through antigen receptor gene engineering. Tumor regression has been observed following transfer of T cells engineered to express chimeric antigen receptors against CD19 in B-cell malignancies or a T-cell receptor against NY-ESO-1 in synovial cell sarcoma and melanoma. Herein, we review recent clinical trials of TILs and antigen receptor gene therapy for advanced cancers. We discuss lessons from this experience and consider how they might be applied to realize the full curative potential of ACT.     

Cancer diagnostic test of Field and Caspary: Part II. A review and interpretation of the collected data

Tables are presented showing data collected to date on the clinical trials of the macrophage electrophoretic mobility test for cancer of Field and Caspary. Seven variations on the original technique are summarized. The original antigen used in these tests was the basic protein of CNS myelin. Four additional proteins have been shown to function in these tests in place of the basic protein. There appears not to be a strong immunological crossreaction between these proteins. This paper discusses a possible solution to the problem of why non-crossreactive proteins appear to crossreact when testing cancer patients with the macrophage electrophoretic mobility related tests. All lymphocytes in saline suspension without added protein will aggregate. This is prevented in normals by the addition of some proteins to the culture, but is not so prevented in cancer and other diseases. Aggregation results in lymphokine release that makes the macrophage electrophoretic mobility test and variants positive. Aggregation occurs in the first incubation step of these tests and this non-immunological aggregation is the underlying phenomenon detected rather than specific antigen recognition as has been heretofore presumed.     

Spontaneous CD4+ and CD8+ T‐cell responses directed against cancer testis antigens are present in the peripheral blood of testicular cancer patients

Cancer/testis antigen (CTAg) expression is restricted to spermatogenic cells in an immune‐privileged site within the testis. However, these proteins are expressed aberrantly by malignant cells and T‐cell responses against CTAgs develop in many cancer patients. We investigated the prevalence, magnitude and phenotype of CTAg‐specific T cells in the blood of patients with testicular germ cell tumors (TGCTs). CD8⁺ and CD4⁺ T‐cell responses against MAGE‐A family antigens were present in 44% (20/45) of patients’ samples assayed by ex vivo IFN‐γ ELISPOT. The presence of MAGE‐specific CD8⁺ T cells was further determined following short‐term in vitro expansion through the use of pMHC‐I multimers containing known immunogenic peptides. Longitudinal analysis revealed that the frequency of MAGE‐specific T cells decreased by 89% following orchidectomy suggesting that persistence of tumor antigen is required to sustain CTAg‐specific T‐cell immunity. Notably, this decrease correlated with a decline in the global effector/memory T‐cell pool following treatment. Spontaneous T‐cell immunity against CTAg proteins therefore develops in many patients with testicular cancer and may play an important role in the excellent clinical outcome of patients with this tumor subtype.     

Cancer diagnostic test of Field and Caspary: Part I. Spontaneous aggregation of lymphocytes in saline suspension is blocked by albumin and histone in normals but not in various disease states: the lymphocyte aggregation blocking test

A blood test is described which is often positive in diverse disease states. In this test washed patient lymphocytes are incubated with histone or albumin. Early aggregation indicates that the patient might have inflammatory, malignant, or other disease, while absence of aggregation is the pattern found in normals. The test is called the lymphocyte aggregation blocking (LAB) test. Positive results when testing cancer patients were 86%, normals 14%, and non-malignant hospitalized patients were 50%. Lymphocyte aggregation was not an active process mediated by added protein. All washed lymphocyte suspensions will aggregate in the test conditions, whether, from normals, cancer or non-cancer patients if no protein is added. Normals' lymphocyte suspensions are prevented from aggregating by the added histone or albumin.     

HLA-II immunopeptidome profiling and deep learning reveal features of antigenicity to inform antigen discovery

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A decade of vaccines: Integrating immunology and vaccinology for rational vaccine design

Vaccination stands as one of the most successful public health measures of the last century. New approaches will be needed, however, to develop highly effective vaccines to prevent tuberculosis, HIV-AIDS, and malaria and to eradicate polio. Current advances in immunology and technology have set the stage for rational vaccine design to begin a "Decade of Vaccines."     

Tumor immunity via homeostatic T cell proliferation: mechanistic aspects and clinical perspectives

Efforts to develop effective anti-tumor immunotherapies are hampered by the difficulty of overcoming tolerance against tumor antigens, which in most instances are normal gene products that are over-expressed, preferentially expressed or re-expressed in cancer cells. Considering that lymphopenia-induced homeostatic T cell proliferation is mediated by self-peptide/MHC recognition and that the expanded cells acquire some effector functions, we hypothesized that this process could be used to break tolerance against tumor antigens. Studies by us and others in several mouse models demonstrated that availability of tumor antigens during homeostatic T cell proliferation indeed leads to effective anti-tumor autoimmunity with specificity and memory. This effect appears to be mediated by reduction in the activation threshold of low-affinity tumor-specific T cells, leading to their preferential engagement and expansion. In its simplicity, this approach is likely to have application in humans, since it relies on conventional lymphopenia-inducing cancer therapies, infusion of autologous lymphocytes and, optimally, tumor-specific vaccination.     

A Quantitative Nitrocellulose Enzyme Immunoassay and its Application to the Screening of Hybrbidomas for the Detection of Uncharacterized Tumor-Associated Antigens in Sera of Cancer Patients

Abstract

An enzyme-linked immunosorbent assay on nitrocellulose based microtiter plates for the detection of uncharacterized tumor associated antigens in squamous cell carcinoma and adenocarcinoma cancer patients' sera is described. Nitrocellulose microtiter plates are more sensitive than the plastic plates of polystyrene and polyvinyl chloride for the detection of antigens in serum. Monoclonal antibodies were selected for their net reactivities toward cancer patients' sera as compared to nomal sera. Sera from benign liver and kidney disease patients and activated human peripheral blood leukocyte supernatant were used to reduce potential false positives toward inflammatory and benign diseases. Using this system, fourteen antibodies were selected out of over eight hundred antibodies for their potential serodiagnostic application.     

The diversity of circulating neutrophils in cancer

Neutrophils, the most abundant leukocyte in human circulation are being more and more recognized as part of the immune reaction to cancer. In the last years, the understanding that neutrophils possess a dual role in cancer development has emerged. During tumor progression the number of neutrophils increase, and their phenotype change. In advanced cancer, we can find several sub-populations of circulating neutrophils possessing different characteristics of maturity, tumor cytotoxicity and immune suppression. One important sub-population of circulating neutrophils is the granulocytic myeloid derived suppressor cells (G-MDSC). Differencing G-MDSC from other sub-populations of neutrophils in the circulation is a complex and controversial task, as there are no clear definitions of the differences between these granulocytic sub-populations. Herein we review the differences described thus far between G-MDSC and other circulating neutrophils. We then compare the morphology, surface markers, function and prognostic importance of the different tumor-related circulating neutrophils, as described by us and others, and discuss the possible relations between the different sub-populations, their source and fate. Lastly, we suggest a nomenclature to try and encompass the full range of circulating neutrophils in cancer.     

Genetics of cancer predisposition and progression

Summary The development of human cancer is a multistep process that entails a progressively more malignant phenotype through the evolution of cellular subsets with increasing numbers of genetic alterations. Here we review the molecular genetics of human cancer predisposition and progression and describe paradigmatic cancer types and cancer syndromes. We also briefly consider the future impact of molecular biology on cancer diagnosis and treatment.Abbreviations APC adenomatous polyposis coli - BWS Beckwith-Wiedemann syndrome - DCC deletion in colorectal cancer - EGFR epidermal growth factor receptor - FAP familial adenomatous polyposis - IGF insulin-like growth factor - LOH loss of heterozygosity - MEN multiple endocrine neoplasia - NF neurofibromatosis - NSCLC non-small-cell lung cancer - RCC renal-cell carcinoma - SCLC small-cell lung cancer - VHL von Hippel-Lindau syndrome - WAGR Wilms' tumor, aniridia, genitourinary anomalies, mental retardation syndrome - WT Wilms' tumor - ZF zinc finger     

Tumor-associated O-glycans of MUC1: Carriers of the glyco-code and targets for cancer vaccine design

The transformation from normal to malignant phenotype in human cancers is associated with aberrant cell-surface glycosylation. It has frequently been reported that MUC1, the heavily glycosylated cell-surface mucin, is altered in both, expression and glycosylation pattern, in human carcinomas of the epithelium. The presence of incomplete or truncated glycan structures, often capped by sialic acid, commonly known as tumor-associated carbohydrate antigens (TACAs), play a key role in tumor initiation, progression, and metastasis. Accumulating evidence suggests that expression of TACAs is associated with tumor escape from immune defenses. In this report, we will give an overview of the oncogenic functions of MUC1 that are exerted through TACA interactions with endogenous carbohydrate-binding proteins (lectins). These interactions often lead to creation of a pro-tumor microenvironment, favoring tumor progression and metastasis, and tumor evasion. In addition, we will describe current efforts in the design of cancer vaccines with special emphasis on synthetic MUC1 glycopeptide vaccines. Analysis of the key factors that govern structure-based design of immunogenic MUC1 glycopeptide epitopes are described. The role of TACA type, position, and density on observed humoral and cellular immune responses is evaluated.     

Strategies for the development of PSA-based vaccines for the treatment of advanced prostate cancer

Prostate cancer is the second leading cause of cancer death in males in the USA. Vaccine strategies represent a novel therapeutic approach. One potential target for a prostate cancer vaccine is prostate-specific antigen (PSA), due to its restricted expression in prostate cancer and normal prostatic epithelial cells. A number of PSAspecific epitopes have been identified that can activate cytotoxic T-lymphocytes (CTLs) and in turn lead to the killing of tumor targets by the peptide-specific CTLs. Strategies have now been employed in clinical trials using RNA-pulsed dendritic cell vaccines, recombinant protein vaccines, and recombinant viral vector delivery of vaccines. Newer approaches incorporating costimulatory molecules that enhance Tcell activation are also being investigated.     

Dock2 in the development of inflammation and cancer

An atypical guanine exchange factor, Dock2 is specifically expressed in hematopoietic cells and regulates activation and migration of immune cells through activating Ras‐related C3 botulinum toxin substrate (Rac). Dock2 was shown to be critical in the development of various inflammatory diseases, including allergic diseases, HIV infection, and graft rejection in organ transplantation. DOCK2 mutation in infants was recently identified to be associated with T and B cell combined immunodeficiency. Furthermore, Dock2 is involved in host protection during enteric bacterial infection and is also associated with the proliferation of cancer cells. It was also shown that patients with digestive tract cancer had high frequency mutation of DOCK2. This review summarizes the latest research progresses on the role of Dock2 for the development of various inflammatory diseases and cancers, and discusses the potential application of Dock2 modulators for patient treatment.     

Aging and cancer: The role of macrophages and neutrophils

Impaired immune function has been implicated in the declining health and higher incidence of cancer in the elderly. However, age-related changes to immunity are not completely understood. Neutrophils and macrophages represent the first line of defence yet their ability to phagocytose pathogens decrease with aging. Cytotoxic T lymphocytes are critical in eliminating tumors, but T cell function is also compromised with aging. T cell responses can be regulated by macrophages and may depend on the functional phenotype macrophages adopt in response to microenvironmental signals. This can range from pro-inflammatory, anti-tumorigenic M1 to anti-inflammatory, pro-tumorigenic M2 macrophages. Macrophages in healthy elderly adipose and hepatic tissue exhibit a more pro-inflammatory M1 phenotype compared to young hosts whilst immunosuppressive M2 macrophages increase in elderly lymphoid tissues, lung and muscle. These M2-like macrophages demonstrate altered responses to stimuli. Recent studies suggest that neutrophils also regulate T cell function and, like macrophages, neutrophil function is modulated with aging. It is possible that age-modified tissue-specific macrophages and neutrophils contribute to chronic low-grade inflammation that is associated with dysregulated macrophage-mediated immunosuppression, which together are responsible for development of multiple pathologies, including cancer. This review discusses recent advances in macrophage and neutrophil biology in healthy aging and cancer.     

纳米粒子应用于电化学癌症早期检测技术的研究进展

利用纳米电化学传感技术进行癌症的早期检测是将来生物医学领域的一个重要发展方向.简要介绍了肿瘤早期检测用标志物的概念和电化学检测这些标志物的原理,对纳米粒子应用于电化学癌症早期检测技术的研究进展进行了详细的评述,最后对该领域的应用前景进行了展望.