Complement and MHC patterns can provide the diagnostic framework for inflammatory neuromuscular diseases

Histopathological analysis stands as the gold standard for the identification and differentiation of inflammatory neuromuscular diseases. These disorders continue to constitute a diagnostic challenge due to their clinical heterogeneity, rarity and overlapping features. To establish standardized protocols for the diagnosis of inflammatory neuromuscular diseases, the development of cost-effective and widely applicable tools is crucial, especially in settings constrained by limited resources. The focus of this review is to emphasize the diagnostic value of major histocompatibility complex (MHC) and complement patterns in the immunohistochemical analysis of these diseases. We explore the immunological background of MHC and complement signatures that characterize inflammatory features, with a specific focus on idiopathic inflammatory myopathies. With this approach, we aim to provide a diagnostic algorithm that may improve and simplify the diagnostic workup based on a limited panel of stainings. Our approach acknowledges the current limitations in the field of inflammatory neuromuscular diseases, particularly the scarcity of large-scale, prospective studies that validate the diagnostic potential of these markers. Further efforts are needed to establish a consensus on the diagnostic protocol to effectively distinguish these diseases.

Proteogenomics Reveal the Overexpression of HLA-I in Cancer

An accurate quantification of HLA class I gene expression is important in understanding the interplay with the tumor microenvironment of antitumor cytotoxic T cell activities. Because HLA-I sequences are highly variable, standard RNAseq and mass spectrometry-based quantification workflows using common genome and protein sequence references do not provide HLA-I allele specific quantifications. Here, we used personalized HLA-I nucleotide and protein reference sequences based on the subjects' HLA-I genotypes and surveyed tumor and adjacent normal samples from patients across nine cancer types. Mass spectrometry using data dependent acquisition data was validated to be sufficient to estimate HLA-A protein expression at the allele level. We found that HLA-I proteins were present in significantly higher levels in tumors compared to adjacent normal tissues from 41 to 63% of head and neck squamous cell carcinoma, uterine corpus endometrial carcinoma, and clear cell renal cell carcinoma patients, and this was driven by increased levels of HLA-I gene transcripts. Most immune cell types are universally enriched in HLA-I high tumors, while endothelial and neuronal cells showed divergent relationships with HLA-I. Pathway analysis revealed that tumor senescence and autophagy activity influence the level of HLA-I proteins in glioblastoma. Genes correlated to HLA-I protein expression are mostly the ones directly involved in HLA-I function in immune response and cell death, while glycosylation genes are exclusively co-expressed with HLA-I at the protein level.

MHC Class I Loss in Triple-negative Breast Cancer: A Potential Barrier to PD-1/PD-L1 Checkpoint Inhibitors

Suppression of the immune system is intimately linked to the development and progression of malignancy, and immune modulating treatment options have shown promise in a variety of tumor types, including some triple-negative breast cancers (TNBC). The most dramatic therapeutic success has been seen with immune checkpoint inhibitors targeting programmed cell death protein 1 (PD-1) and its ligand, PD-L1. Difficulty remains, however, in appropriate patient selection for treatment, as many PD-L1-positive cancers fail to show durable responses to PD-1/PD-L1 inhibition. Checkpoint inhibitor targeting of the adaptive immune response relies on the presence of major histocompatibility complex (MHC) class I molecules on the tumor cell surface for tumor antigen presentation. MHC class I loss has been previously described in breast cancer and represents a putative mechanism of immunotherapeutic resistance in this tumor type. One hundred seventeen invasive primary breast carcinomas with a range of histologic subtypes were evaluated on tissue microarrays containing formalin-fixed paraffin-embedded tissue. Loss of MHC class I expression was common among breast cancers, with greater than half of cases demonstrating either subclonal or diffuse loss. Fifty-nine percent of TNBC demonstrated loss of MHC class I, including 46% of those meeting the Food and Drug Administration-approved threshold of 1% for tumor-associated immune cell PD-L1 expression. MHC class I loss was particularly common in the apocrine subtype of TNBC (78%). MHC class I's employment as a predictive biomarker should be considered, as its loss may represent a barrier to successful enhancement of the antitumor adaptive immune response by PD-1/PD-L1 inhibition.

Presumption of guilt for T cells in type 1 diabetes: lead culprits or partners in crime depending on age of onset?

Available evidence provides arguments both for and against a primary pathogenic role for T cells in human type 1 diabetes. Genetic susceptibility linked to HLA Class II lends strong support. Histopathology documents HLA Class I hyperexpression and islet infiltrates dominated by CD8+ T cells. While both hallmarks are near absent in autoantibody-positive donors, the variable insulitis and residual beta cells of recent-onset donors suggests the existence of a younger-onset endotype with more aggressive autoimmunity and an older-onset endotype with more vulnerable beta cells. Functional arguments from ex vivo and in vitro human studies and in vivo 'humanised' mouse models are instead neutral or against a T cell role. Clinical support is provided by the appearance of islet autoantibodies before disease onset. The faster C-peptide loss and superior benefits of immunotherapies in individuals with younger-onset type 1 diabetes reinforce the view of age-related endotypes. Clarifying the relative role of T cells will require technical advances in the identification of their target antigens, in their detection and phenotyping in the blood and pancreas, and in the study of the T cell/beta cell crosstalk. Critical steps toward this goal include the understanding of the link with environmental triggers, the description of T cell changes along the natural history of disease, and their relationship with age and the 'benign' islet autoimmunity of healthy individuals. Graphical abstract.

Effects of obesity on NK cells in a mouse model of postmenopausal breast cancer

Obesity is a widely spread disease and a crucial risk factor for malign disorders, including breast cancer of women in the postmenopause. Studies demonstrated that in case of obesity crucial natural killer (NK) cell functions like combating tumor cells are affected. This study aims to analyze NK cells and NK cell receptor expression of obese mice in a model for postmenopausal breast cancer. Therefore, female BALB/c mice were fed either a high fat or a standard diet. Thereafter, ovaries were ectomized and a syngeneic and orthotopical injection of 4T1-luc2 mouse mammary tumor cells into the mammary adipose tissue pad was performed. Obese mice showed increased body weights and visceral fat mass as well as increased levels of leptin and IL-6 in plasma. Moreover, compared to the lean littermates, tumor growth was increased and the NKp46-expression on circulating NK cells was decreased. Furthermore, the activating NK cell receptor NKG2D ligand (MULT1) expression was enhanced in adipose tissue of obese tumor bearing mice. The present study gives novel insights into gene expression of NK cell receptors in obesity and aims to promote possible links of the obesity-impaired NK cell physiology and the elevated breast cancer risk in obese women.

Quantification of Neonatal Fc Receptor and Beta-2 Microglobulin in Human Liver Tissues by Ultraperformance Liquid Chromatography-Multiple Reaction Monitoring-based Targeted Quantitative Proteomics for Applications in Biotherapeutic Physiologically-based Pharmacokinetic Models

Neonatal Fc receptor (FcRn) and beta-2 microglobulin (β2M) play an important role in transporting maternal IgG to fetuses, maintaining the homeostasis of IgG and albumin in human body, and prolonging the half-life of IgG- or albumin-based biotherapeutics. Little is known about the influence of age, gender and race, and interindividual variability of human FcRn and β2M on the protein level. In this study, an ultraperformance liquid chromatography-multiple reaction monitoring mass spectrometry-based targeted quantitative proteomic method was developed and optimized for the quantification of human FcRn and β2M. Among the 39 human livers studied (age 13-80 years), the mean (±S.D.) concentrations of FcRn and β2M were 147 (±39) and 1250 (±460) pmol/g of liver tissue, respectively. A four-fold interindividual variability (63-243 pmol/g of liver tissue) was observed for the hepatic FcRn concentration. A moderate correlation was found between the hepatic β2M and FcRn expression levels. Influences of age, gender, and race on the hepatic expression of FcRn and β2M were evaluated. The findings from this study may aid the development of physiologically-based pharmacokinetic models that incorporate empirical FcRn tissue concentrations and interindividual variabilities, and the development of personalized dosing of biopharmaceuticals. SIGNIFICANCE STATEMENT: This is the first study to evaluate the influence of age, gender, and race on the expression of neonatal Fc receptor (FcRn) and beta-2 microglobulin (β2M) and their interindividual variability in human livers. This study describes a validated ultraperformance liquid chromatography-multiple reaction monitoring-based targeted quantitative proteomic method for quantifying human FcRn and β2M in biological tissues. Results from this study may aid current development of physiologically-based pharmacokinetic models for biotherapeutics, where FcRn plays a significant role in clearance mechanism, and its expression level and interindividual variability are largely unknown.

Impacts of combining anti-PD-L1 immunotherapy and radiotherapy on the tumour immune microenvironment in a murine prostate cancer model

BACKGROUND

Radiotherapy enhances innate and adaptive anti-tumour immunity. It is unclear whether this effect may be harnessed by combining immunotherapy with radiotherapy fractions used to treat prostate cancer. We investigated tumour immune microenvironment responses of pre-clinical prostate cancer models to radiotherapy. Having defined this landscape, we tested whether radiotherapy-induced tumour growth delay could be enhanced with anti-PD-L1.

METHODS

Hypofractionated radiotherapy was delivered to TRAMP-C1 and MyC-CaP flank allografts. Tumour growth delay, tumour immune microenvironment flow-cytometry, and immune gene expression were analysed. TRAMP-C1 allografts were then treated with 3 × 5 Gy ± anti-PD-L1.

RESULTS

3 × 5 Gy caused tumour growth delay in TRAMP-C1 and MyC-CaP. Tumour immune microenvironment changes in TRAMP-C1 at 7 days post-radiotherapy included increased tumour-associated macrophages and dendritic cells and upregulation of PD-1/PD-L1, CD8+ T-cell, dendritic cell, and regulatory T-cell genes. At tumour regrowth post-3 × 5 Gy the tumour immune microenvironment flow-cytometry was similar to control tumours, however CD8+, natural killer and dendritic cell gene transcripts were reduced. PD-L1 inhibition plus 3 × 5 Gy in TRAMP-C1 did not enhance tumour growth delay versus monotherapy.

CONCLUSION

3 × 5 Gy hypofractionated radiotherapy can result in tumour growth delay and immune cell changes in allograft prostate cancer models. Adjuncts beyond immunomodulation may be necessary to improve the radiotherapy-induced anti-tumour response.

An effective peptide vaccine strategy circumventing clonal MHC heterogeneity of murine myeloid leukaemia

BACKGROUND

Therapeutic cancer vaccines are an attractive approach for treating malignant tumours, and successful tumour eradication depends primarily on controlling tumour immunosuppression status as well as heterogeneity of tumour cells driven by epigenetic alterations.

METHODS

Peptide-loaded dendritic cell (DC) prime and non-infectious peptide booster heterologous immunisations were assessed for the immunogenicity of polo-like kinase-1 (PLK1)-derived peptides. Heterologous vaccination regimen targeting multiple shared tumour antigens simultaneously with PD-L1 blockade was assessed against murine myeloid leukaemia.

RESULTS

A synthetic PLK1122 (DSDFVFVVL)-based heterologous vaccination generated large numbers of long-lasting antigen-specific CD8 T-cells eliciting therapeutic effects against various established tumours. The therapeutic efficacy of single antigen-targeting PLK1122-based vaccine with sufficient endurance of PD-L1 blockade toward C1498 leukaemia relied on the heterogeneous clonal levels of MHC-I and PD-L1 expression. A novel multi-peptide-based vaccination targeting PLK1 and survivin simultaneously along with PD1 blockade led to complete tumour eradication and long-term survival in mice with clonally heterologous C1498 myeloid leukaemia.

CONCLUSIONS

Our findings suggest that PLK1 could be an attractive immunotherapeutic target antigen for cancer immunotherapy, and that similar strategies would be applicable for the optimisation of cancer vaccines for the treatment of numerous viral diseases and malignant tumours.

Expression of classical human leukocyte antigen class I antigens, HLA-E and HLA-G, is adversely prognostic in pancreatic cancer patients

The expression of classical human leukocyte antigen class I antigens (HLA-I) on the surfaces of cancer cells allows cytotoxic T cells to recognize and eliminate these cells. Reduction or loss of HLA-I is a mechanism of escape from antitumor immunity. The present study aimed to investigate the clinicopathological impacts of HLA-I and non-classical HLA-I antigens expressed on pancreatic ductal adenocarcinoma (PDAC) cells. We performed immunohistochemistry to detect expression of HLA-I antigens in PDAC using 243 PDAC cases and examined their clinicopathological influences. We also investigated the expression of immune-related genes to characterize PDAC tumor microenvironments. Lower expression of HLA-I, found in 33% of PDAC cases, was significantly associated with longer overall survival. Higher expression of both HLA-E and HLA-G was significantly associated with shorter survival. Multivariate analyses revealed that higher expression of these three HLA-I antigens was significantly correlated with shorter survival. Higher HLA-I expression on PDAC cells was significantly correlated with higher expression of IFNG, which also correlated with PD1, PD-L1 and PD-L2 expression. In vitro assay revealed that interferon gamma (IFNγ) stimulation increased surface expression of HLA-I in three PDAC cell lines. It also upregulated surface expression of HLA-E, HLA-G and immune checkpoint molecules, including PD-L1 and PD-L2. These results suggest that the higher expression of HLA-I, HLA-E and HLA-G on PDAC cells is an unfavorable prognosticator. It is possible that IFNγ promotes a tolerant microenvironment by inducing immune checkpoint molecules in PDAC tissues with higher HLA-I expression on PDAC cells.

The inhibitory receptor CD94/NKG2A on CD8+ tumor-infiltrating lymphocytes in colorectal cancer: a promising new druggable immune checkpoint in the context of HLAE/β2m overexpression

We previously demonstrated that HLA-E/β2m overexpression by tumor cells in colorectal cancers is associated with an unfavorable prognosis. However, the expression of its specific receptor CD94/NKG2 by intraepithelial tumor-infiltrating lymphocytes, their exact phenotype and function, as well as the relation with the molecular status of colorectal cancer and prognosis remain unknown. Based on a retrospective cohort of 234 colorectal cancer patients, we assessed the expression of HLA-E, β2m, CD94, CD8, and NKp46 by immunohistochemistry on tissue microarray. The expression profile of HLA-E/β2m on tumor cells and the density of tumor-infiltrating lymphocytes were correlated to the clinicopathological and molecular features (Microsatellite status, BRAF and RAS mutations). Then, from the primary tumors of 27 prospective colorectal cancers, we characterized by multiparameter flow cytometry the nature (T and/or NK cells) and the co-expression of the inhibitory NKG2A or activating NKG2C chain of ex vivo isolated CD94+ tumor-infiltrating lymphocytes. Their biological function was determined using an in vitro redirected cytolytic activity assay. Our results showed that HLA-E/β2m was preferentially overexpressed in microsatellite instable tumors compared with microsatellite stable ones (45% vs. 19%, respectively, p = 0.0001), irrespective of the RAS or BRAF mutational status. However, HLA-E/β2m+ colorectal cancers were significantly enriched in CD94+ intraepithelial tumor-infiltrating lymphocytes in microsatellite instable as well as in microsatellite stable tumors. Those CD94+ tumor-infiltrating lymphocytes mostly corresponded to CD8+ αβ T cells, and  to a lesser extent to NK cells, and mainly co-expressed a functional inhibitory NKG2A chain. Finally, a high number of CD94+ intraepithelial tumor-infiltrating lymphocytes in close contact with tumor cells was independently associated with a worse overall survival. In conclusion, these findings strongly suggest that HLA-E/β2m-CD94/NKG2A represents a new druggable inhibitory immune checkpoint, preferentially expressed in microsatellite instable tumors, but also in a subgroup of microsatellite stable tumors, leading to a new opportunity in colorectal cancer immunotherapies.

Rainbow Trout Red Blood Cells Exposed to Viral Hemorrhagic Septicemia Virus Up-Regulate Antigen-Processing Mechanisms and MHC I&II, CD86, and CD83 Antigen-presenting Cell Markers

Nucleated teleost red blood cells (RBCs) are known to express molecules from the major histocompatibility complex and peptide-generating processes such as autophagy and proteasomes, but the role of RBCs in antigen presentation of viruses have not been studied yet. In this study, RBCs exposed ex vivo to viral hemorrhagic septicemia virus (VHSV) were evaluated by means of transcriptomic and proteomic approaches. Genes and proteins related to antigen presentation molecules, proteasome degradation, and autophagy were up-regulated. VHSV induced accumulation of ubiquitinated proteins in ex vivo VHSV-exposed RBCs and showed at the same time a decrease of proteasome activity. Furthermore, induction of autophagy was detected by evaluating LC3 protein levels. Sequestosome-1/p62 underwent degradation early after VHSV exposure, and it may be a link between ubiquitination and autophagy activation. Inhibition of autophagosome degradation with niclosamide resulted in intracellular detection of N protein of VHSV (NVHSV) and p62 accumulation. In addition, antigen presentation cell markers, such as major histocompatibility complex (MHC) class I & II, CD83, and CD86, increased at the transcriptional and translational level in rainbow trout RBCs exposed to VHSV. In summary, we show that nucleated rainbow trout RBCs can degrade VHSV while displaying an antigen-presenting cell (APC)-like profile.

Soluble HLA-I and HLA-II Molecules Are Potential Prognostic Markers of Progression of Systemic and Local Inflammation in Patients with COPD

Soluble molecules of the major histocompatibility complex play an important role in the development of various immune-mediated diseases. However, there is not much information on the participation of these proteins in the pathogenesis of chronic obstructive pulmonary disease (COPD). The aim of our work was to determine the content of soluble molecules of the major histocompatibility complex of classes I and II (sHLA-I and sHLA-II) in the exhaled breath condensate (EBC) and in the blood serum in patients with moderate to severe COPD during the exacerbation and stable phase. We investigated 105 patients (male) with COPD aged 46-67 and 21 healthy nonsmoking volunteers (male) comparable in age. The content of sHLA-I and sHLA-II molecules was studied using ELISA. We found an increase in the level of sHLA-I and sHLA-II molecules in EBC, as well as an enhancement in the serum content of sHLA-II in all the examined COPD patients compared to healthy nonsmoking volunteers. The revealed negative correlation between the serum concentration of sHLA-II and values of FEV1 and FEV1/FVC in all examined patients with COPD gives a possibility to consider the content of these proteins as an additional systemic marker of disease severity. The maximum endobronchial and serum concentrations of sHLA-I and sHLA-II were detected in patients with severe COPD during the exacerbation. The negative associations between the content of these molecules in EBC and serum and the parameters of lung function in patients with severe COPD were established. These findings suggest a pathogenetic role of sHLA-I and sHLA-II molecules in the mechanisms of the development and progression of local and systemic inflammation in COPD.

Natural Killer T Cells and Mucosal-Associated Invariant T Cells in Lung Infections

The immune system has been traditionally divided into two arms called innate and adaptive immunity. Typically, innate immunity refers to rapid defense mechanisms that set in motion within minutes to hours following an insult. Conversely, the adaptive immune response emerges after several days and relies on the innate immune response for its initiation and subsequent outcome. However, the recent discovery of immune cells displaying merged properties indicates that this distinction is not mutually exclusive. These populations that span the innate-adaptive border of immunity comprise, among others, CD1d-restricted natural killer T cells and MR1-restricted mucosal-associated invariant T cells. These cells have the unique ability to swiftly activate in response to non-peptidic antigens through their T cell receptor and/or to activating cytokines in order to modulate many aspects of the immune response. Despite they recirculate all through the body via the bloodstream, these cells mainly establish residency at barrier sites including lungs. Here, we discuss the current knowledge into the biology of these cells during lung (viral and bacterial) infections including activation mechanisms and functions. We also discuss future strategies targeting these cell types to optimize immune responses against respiratory pathogens.

Minimal Information About an Immuno-Peptidomics Experiment (MIAIPE)

Minimal information about an immuno-peptidomics experiment (MIAIPE) is an initiative of the members of the Human Immuno-Peptidome Project (HIPP), an international program organized by the Human Proteome Organization (HUPO). The aim of the MIAIPE guidelines is to deliver technical guidelines representing the minimal information required to sufficiently support the evaluation and interpretation of immunopeptidomics experiments. The MIAIPE document has been designed to report essential information about sample preparation, mass spectrometric measurement, and associated mass spectrometry (MS)-related bioinformatics aspects that are unique to immunopeptidomics and may not be covered by the general proteomics MIAPE (minimal information about a proteomics experiment) guidelines.

Computational Tools for the Identification and Interpretation of Sequence Motifs in Immunopeptidomes

Recent advances in proteomics and mass-spectrometry have widely expanded the detectable peptide repertoire presented by major histocompatibility complex (MHC) molecules on the cell surface, collectively known as the immunopeptidome. Finely characterizing the immunopeptidome brings about important basic insights into the mechanisms of antigen presentation, but can also reveal promising targets for vaccine development and cancer immunotherapy. This report describes a number of practical and efficient approaches to analyze immunopeptidomics data, discussing the identification of meaningful sequence motifs in various scenarios and considering current limitations. Guidelines are provided for the filtering of false hits and contaminants, and to address the problem of motif deconvolution in cell lines expressing multiple MHC alleles, both for the MHC class I and class II systems. Finally, it is demonstrated how machine learning can be readily employed by non-expert users to generate accurate prediction models directly from mass-spectrometry eluted ligand data sets.

Mass Spectrometry Based Immunopeptidomics for the Discovery of Cancer Neoantigens

Recent data indicate that endogenous mutated cancer proteins can be processed and presented as HLA binding peptides, leading to their recognition in vivo as "non-self." Targeting such neoantigens would enable immune cells to distinguish between normal and cancerous cells, avoiding the risk of autoimmunity. So far, discovery of such neoantigens relies mainly on prediction-based interrogation of the "mutanome" using genomic information as input, followed by highly laborious and time-consuming T cell screening assays. Currently, mass spectrometry is the only unbiased methodology to comprehensively interrogate the naturally presented repertoire of HLA binding peptides, including peptides derived from tumor-associated antigens and post-translational modified peptides. This chapter describes a detailed protocol for in-depth and accurate mass spectrometry based immunopeptidomics, enabling the direct identification of tissue-derived neoantigens extracted from human tumors.

HLA class I expression predicts prognosis and therapeutic benefits from tyrosine kinase inhibitors in metastatic renal-cell carcinoma patients

PURPOSE

Classical HLA class I antigen is highly involved in antigen presentation and adaptive immune response against tumor. In this study, we explored its predictive value for treatment response and survival in metastatic renal-cell carcinoma (mRCC) patients.

EXPERIMENTAL DESIGN

A TKI cohort of 111 mRCC patients treated with sunitinib or sorafenib and a non-TKI cohort of 160 mRCC patients treated with interleukin-2 or interferon-α-based immunotherapy at a single institution were retrospectively enrolled. HLA class I expression and cytotoxic T lymphocyte (CTL) density was assessed by immunohistochemistry on tissue microarrays. Association between HLA class I and CTL was also assessed in the TCGA KIRC cohort.

RESULTS

In the TKI cohort, down-regulated HLA class I was associated with lower objective response rate of TKI therapy (P = 0.004), shorter overall survival (OS) (P = 0.001), and shorter progression free survival (PFS) (P < 0.001). Multivariate Cox regression model defined HLA expression as an independent prognostic factor for both OS [hazard ratio 1.687 (95% CI 1.045-2.724), P = 0.032] and PFS [hazard ratio 2.139 (95% CI 1.376-3.326), P = 0.001]. In the non-TKI cohort, HLA class I was not significantly associated with survival. HLA class I expression was associated with CTL infiltration and function, and its prognostic value was more predominant in CTL high-density tumors (P < 0.001) rather than CTL low-density tumors (P = 0.294).

CONCLUSIONS

Classical HLA class I expression can serve as a potential predictive biomarker for TKI therapy in mRCC patients. Its predictive value was restricted in CTL high-density tumors. However, further external validations and functional investigations are still required.

The prognostic benefit of tumour-infiltrating Natural Killer cells in endometrial cancer is dependent on concurrent overexpression of Human Leucocyte Antigen-E in the tumour microenvironment

BACKGROUND

Human Leucocyte Antigen- E (HLA-E) has been reported as both a positive and negative prognostic marker in cancer. This apparent discrepancy may be due to opposing actions of HLA-E on tumour-infiltrating immune cells. Therefore, we evaluated HLA-E expression and survival in relation to the presence of intratumoural natural killer (NK) cells and cytotoxic T cells (CTLs).

METHODS

Tissue microarrays (TMAs) of endometrial tumours were used for immunohistochemical staining of parameters of interest. The combined impact of clinical, pathological and immune parameters on survival was analysed using log rank testing and Cox regression analyses.

RESULTS

Upregulation of HLA-E was associated with an improved disease-free and disease-specific survival in univariate analysis (HR 0.58 95% CI 0.37-0.89; HR 0.42 95% CI 0.25-0.73, respectively). In multivariate analysis, the presence of NK cells predicts survival with a hazard ratio (HR) 0.28 (95% confidence interval (CI) 0.09-0.91) when HLA-E expression is upregulated; but it is associated with a worse prognosis when HLA-E expression is normal (HR 13.43, 95% CI 1.70-106.14). By contrast, the prognostic benefit of T cells was not modulated by HLA-E expression.

CONCLUSIONS

Taken together, we demonstrate that the prognostic benefit of NK cells, but not T-cells, is influenced by HLA-E expression in endometrial cancer (EC) and propose a model to explain our observations.

Suppression of Type I IFN Signaling in Tumors Mediates Resistance to Anti-PD-1 Treatment That Can Be Overcome by Radiotherapy

Immune checkpoint therapies exhibit impressive efficacy in some patients with melanoma or lung cancer, but the lack of response in most cases presses the question of how general efficacy can be improved. In addressing this question, we generated a preclinical tumor model to study anti-PD-1 resistance by in vivo passaging of Kras-mutated, p53-deficient murine lung cancer cells (p53^R172HΔg/+K-ras^LA1/+ ) in a syngeneic host exposed to repetitive dosing with anti-mouse PD-1 antibodies. PD-L1 (CD274) expression did not differ between the resistant and parental tumor cells. However, the expression of important molecules in the antigen presentation pathway, including MHC class I and II, as well as β2-microglobulin, were significantly downregulated in the anti-PD-1-resistant tumors compared with parental tumors. Resistant tumors also contained fewer CD8⁺ (CD8α) and CD4⁺ tumor-infiltrating lymphocytes and reduced production of IFNγ. Localized radiotherapy induced IFNβ production, thereby elevating MHC class I expression on both parental and resistant tumor cells and restoring the responsiveness of resistant tumors to anti-PD-1 therapy. Conversely, blockade of type I IFN signaling abolished the effect of radiosensitization in this setting. Collectively, these results identify a mechanism of PD-1 resistance and demonstrate that adjuvant radiotherapy can overcome resistance. These findings have immediate clinical implications for extending the efficacy of anti-PD-1 immune checkpoint therapy in patients. Cancer Res; 77(4); 839-50. ©2016 AACR.

Cathepsin G-mediated proteolytic degradation of MHC class I molecules to facilitate immune detection of human glioblastoma cells

To mount an adaptive immune response, MHC I molecules present antigenic peptides to CTLs. Transcriptional reduction of MHC I molecules is a strategy of immune evasion, which impairs the detection of infected or tumorous cells by CTLs. Natural killer (NK) cells, on the other hand, eliminate target cells specifically in the absence of MHC I. Consequently, infected or tumorous cells partly retain their MHC I at the cell surface to avoid NK recognition. However, it remains unclear which protease degrades MHC I molecules and how these cells maintain a limited set of MHC I at the cell surface. Here, we demonstrate that cathepsin G (CatG), a serine protease, found in the endocytic compartment of APCs and, to a lesser extent, CatD and CatS proteolytically degrade MHC I molecules. Inhibition of CatG boosted MHC I expression at the cell surface of primary human immune cells. In contrast, human glioblastoma cells do not harbor active CatG and might have lost the ability to proteolytically degrade MHC I during tumorigenesis to avoid NK-mediated killing. Overexpression of CatG in glioblastoma cells resulted in a rapid and efficient MHC I degradation. In conclusion, CatG is an essential protease for regulating MHC I molecules and thus modulation of CatG activity might present a new avenue for therapeutic intervention.

Decellularization of Human Nasal Septal Cartilage for the Novel Filler Material of Vocal Fold Augmentation

OBJECTIVES

The clinical application of allogenic and/or xenogenic cartilage for vocal fold augmentation requires to remove the antigenic cellular component. The objective of this study was to assess the effect of cartilage decellularization and determine the change in immunogenicity after detergent treatment in human nasal septal cartilage flakes made by the freezing and grinding method.

METHODS

Human nasal septal cartilages were obtained from surgical cases. The harvested cartilages were treated by the freezing and grinding technique. The obtained cartilage flakes were treated with 1% Triton X-100 or 2% sodium dodecyl sulfate (SDS) for decellularization of the cartilage flakes. Hematoxylin and eosin stain (H&E stain), surface electric microscopy, immunohistochemical stain for major histocompatibility complex I and II, and ELISA for DNA contents were performed to assess the effect of cartilage decellularization after detergent treatment.

RESULTS

A total of 10 nasal septal cartilages were obtained from surgical cases. After detergent treatment, the average size of the cartilage flakes was significantly decreased. With H&E staining, the cell nuclei of decellularized cartilage flakes were not observed. The expression of major histocompatibility complex (MHC)-I and II antigens was not identified in the decellularized cartilage flakes after treatment with detergent. DNA content was removed almost entirely from the decellularized cartilage flakes.

CONCLUSION

Treatment with 2% SDS or 1% Triton X-100 for 1 hour appears to be a promising method for decellularization of human nasal septal cartilage for vocal fold augmentation.

Soluble ligands for the NKG2D receptor are released during endometriosis and correlate with disease severity

BACKGROUND

Endometriosis is a benign gynaecological disease. Abundant bulk of evidence suggests that patients with endometriosis have an immunity dysfunction that enables ectopic endometrial cells to implant and proliferate. Previous studies show that natural killer cells have a pivotal role in the immune control of endometriosis.

METHODS AND FINDINGS

This is a prospective laboratory study conducted in a tertiary-care university hospital between January 2011 and April 2013. We investigated non-pregnant, younger than 42-year-old patients (n= 202) during surgery for benign gynaecological conditions. After complete surgical exploration of the abdominopelvic cavity, 121 women with histologically proven endometriosis and 81 endometriosis-free controls women were enrolled. Patients with endometriosis were classified according to a surgical classification in three different types of endometriosis: superficial peritoneal endometriosis (SUP), ovarian endometrioma (OMA) and deep infiltrating endometriosis (DIE). Peritoneal fluid samples were obtained from all study participants during the surgery in order to detect soluble NKG2D ligands (MICA, MICB and ULBP-2). When samples with undetectable peritoneal fluid levels of MICA, MICB and ULBP-2 were excluded, MICA ratio levels were significantly higher in endometriosis patients than in controls (median, 1.1 pg/mg; range, 0.1-143.5 versus median, 0.6 pg/mg; range, 0.1-3.5; p=0.003). In a similar manner peritoneal fluid MICB levels were also increased in endometriosis-affected patients compared with disease-free women (median, 4.6 pg/mg; range, 1.2-4702 versus median, 3.4 pg/mg; range, 0.7-20.1; p=0.001). According to the surgical classification, peritoneal fluid soluble MICA, MICB and ULBP-2 ratio levels were significantly increased in DIE as compared to controls (p=0.015, p=0.003 and p=0.045 respectively). MICA ratio levels also correlated with dysmenorrhea (r=0.232; p=0.029), total rAFS score (r=0.221; p=0.031) and adhesions rAFS score (r=0.221; p=0.031).

CONCLUSIONS

We demonstrate a significant increase of peritoneal fluid NKG2D ligands in women with endometriosis especially in those cases presenting DIE. This study suggests that NKG2D ligands shedding is a novel pathway in endometriosis complex pathogenesis that impairs NK cell function.

An analysis of the sensitivity and specificity of MHC-I and MHC-II immunohistochemical staining in muscle biopsies for the diagnosis of inflammatory myopathies

Although there have been several previous reports of immunohistochemical staining for MHC antigens in muscle biopsies, there appears to be a lack of consensus about its routine use in the diagnostic evaluation of biopsies from patients with suspected inflammatory myopathy. Positive MHC-I staining is nonspecific but is widely used as a marker for inflammatory myopathy, whilst the role of MHC-II staining is not clearly defined. We investigated the sensitivity and specificity of MHC-I and MHC-II immunostaining for the diagnosis of inflammatory myopathy in a large group of biopsies from a single reference laboratory. Positive staining for MHC-I was found to have a high sensitivity in biopsies from patients with inflammatory myopathy but a very low specificity, as it was also common in other non-inflammatory myopathies and neurogenic disorders. On the other hand, MHC-II positivity had a much higher specificity in all major subgroups of inflammatory myopathy, especially inclusion body myositis. The findings indicate that the combination of MHC-I and MHC-II staining results in a higher degree of specificity for the diagnosis of inflammatory myopathy and that in biopsies with inflammation, positive MHC-II staining strongly supports the diagnosis of an immune-mediated myopathy. We recommend that immunohistochemical staining for both MHC-I and MHC-II should be included routinely in the diagnostic evaluation of muscle biopsies from patients with suspected inflammatory myopathy. However, as the sensitivity and interpretation of MHC staining may depend on the technique used, further studies are needed to compare procedures in different centres and develop standardised protocols.

Loss of expression of MHC class I-related chain A (MICA) is a frequent event and predicts poor survival in patients with hepatocellular carcinoma

Natural killer (NK) cells are important effector cells for the first line of defense against tumor. Distant MHC class I homolog MICA has been identified as human ligand for NK cell activating receptor NKG2D. Engagement of MICA triggers NK cells and augments antigen-specific CTL anti-tumor immunity. However, the expression level of MICA and its clinical significance in hepatocellular carcinoma remains to be elucidated. In the present study, a hospital-based study cohort of 143 HCC patients was involved. MICA expression levels were determined by immunohistochemical staining. The association of MICA expression with tumor clinicopathologic features, disease-free survival, and overall survival of HCC patients were analyzed. Significantly decreased expression of MICA was detected in tumor specimens. MICA expression was significantly associated with AFP level (P < 0.001) and tumor node metastasis stage (P = 0.003). Patients with reduced level of MICA had a statistically significantly shorter disease-free survival and overall survival duration than patients with preserved expression of MICA. However, in multivariate analysis, MICA expression level was found not to be an independent prognostic factor for both disease-free survival and overall survival of HCC patients. Our findings suggest that decreased MICA expression may play an important role in HCC tumor evasion of host immunity, which warrants further investigation in future studies.

Expression of HLA class I antigen, aspirin use, and survival after a diagnosis of colon cancer

IMPORTANCE

Use of aspirin (which inhibits platelet function) after a colon cancer diagnosis is associated with improved overall survival. Identifying predictive biomarkers of this effect could individualize therapy and decrease toxic effects.

OBJECTIVE

To demonstrate that survival benefit associated with low-dose aspirin use after a diagnosis of colorectal cancer might depend on HLA class I antigen expression.

DESIGN, SETTING, AND PARTICIPANTS

A cohort study with tumor blocks from 999 patients with colon cancer (surgically resected between 2002 and 2008), analyzed for HLA class I antigen and prostaglandin endoperoxide synthase 2 (PTGS2) expression using a tissue microarray. Mutation analysis of PIK3CA was also performed. Data on aspirin use after diagnosis were obtained from a prescription database. Parametric survival models with exponential (Poisson) distribution were used to model the survival.

MAIN OUTCOMES AND MEASURES

Overall survival.

RESULTS

The overall survival benefit associated with aspirin use after a diagnosis of colon cancer had an adjusted rate ratio (RR) of 0.53 (95% CI, 0.38-0.74; P < .001) when tumors expressed HLA class I antigen compared with an RR of 1.03 (0.66-1.61; P = .91) when HLA antigen expression was lost. The benefit of aspirin was similar for tumors with strong PTGS2 expression (0.68; 0.48-0.97; P = .03), weak PTGS2 expression (0.59; 0.38-0.97; P = .02), and wild-type PIK3CA tumors (0.55; 0.40-0.75; P < .001). No association was observed with mutated PIK3CA tumors (0.73; 0.33-1.63; P = .44).

CONCLUSIONS AND RELEVANCE

Contrary to the original hypothesis, aspirin use after colon cancer diagnosis was associated with improved survival if tumors expressed HLA class I antigen. Increased PTGS2 expression or the presence of mutated PIK3CA did not predict benefit from aspirin. HLA class I antigen might serve as a predictive biomarker for adjuvant aspirin therapy in colon cancer.

Tumor immune subtypes distinguish tumor subclasses with clinical implications in breast cancer patients

There is strong evidence that the host's cellular immune response is linked to tumor progression, however its impact on patient outcome in breast cancer is poorly understood. The purpose of this study is to define tumor immune subtypes, focusing on cellular immune responses and investigate their prognostic effect in breast cancer patients. Our training (n = 440) and validation cohort (n = 382) consisted of all early breast cancer patients primarily treated with surgery in our center between 1985 and 1996. Tumor tissue sections were immunohistochemically stained for CD8 (CTL) and PEN5 (NK cells). Tumor expression of classical and non-classical human leukocyte antigen class I, and tumor-infiltrating Tregs were previously determined. Tumor immune subtypes were constructed based on quantification of these markers and biological rationale. High, intermediate, and low immune susceptible tumor immune subtypes were found, respectively, in 16, 63, and 20 % of patients in the training cohort and 16, 71, and 13 % in the validation cohort. The subtypes showed to be statistically significant prognostic in multivariate analyses for relapse free period (RFP) [p < 0.0001, intermediate versus high: hazard ratio (HR) 1.95; low versus high HR 2.98] and relative survival (RS) (p = 0.006, intermediate versus high HR 3.84; low versus high: HR 4.26). Validation of these outcome analyses confirmed the independent prognostic associations: RFP (p = 0.025) and RS (p = 0.040). The tumor immune subtypes that we present represent a prognostic profile with solid underlying biological rationale and with high discriminative power confirmed in an independent validation cohort. Our results emphasize the importance of tumor immune surveillance in the control of tumor development and, therefore, in determining patient prognosis. Tumor immune subtype profiling is promising for prognosis prediction and the achievement of tailored treatment for breast cancer patients.

Differential expression of immune-modulatory molecule HLA-E in non-neoplastic and neoplastic lesions of the thyroid

Human leukocyte antigen (HLA)–E is a non-classical molecule of the histocompatibility complex that functions as one of the main ligands of the Natural Killer (NK) cell inhibitory receptor CD94/NKG2A and inhibits its potent cytotoxic activity. Due to the important role of NK cells in combating neoplasm, we hypothesized that the differential expression of HLA-E could favor the progression of heterogeneous thyroid tumors.Using an immunohistochemistry technique in 143 biopsies of thyroid tumors, including benign and malignant neoplasms and goiters, we evaluated the expression of HLA-E among various tumor types and its association with the clinicopathological factors of diseases. We verified high HLA-E expression in all types of neoplastic tumors, although no significant differences between the groups were found. Low expression was observed in 95 percent of the goiter samples, showing significant differences between neoplastic and non-neoplastic lesions. Furthermore, a significant result was found with regard to the tumor size, with high HLA-E expression being related to smaller tumors. Therefore, our data suggest that an increase in HLA-E may be associated with the establishment of thyroid neoplasms, with either benign or malignant features.

Enhancement of natural killer cell effector functions against selected lymphoma and leukemia cell lines by dasatinib

As NK cell immunotherapy is still poorly successful, combinations with drugs enhancing NK cell activity are of major interest. NK large granular lymphocyte expansions associated with improved survival have been described under monotherapy with the Bcr-Abl/Src inhibitor dasatinib, which inhibits NK cell functions in vitro. As Src kinases play a major role in inhibitory and activating signaling pathways of NK cells, both outcomes appear plausible. To clarify these contradictory observations and potentially enable the use of dasatinib as adjuvant, we analyzed how clinically relevant doses promote NK cell effector functions. Polyclonal human NK cells were studied ex vivo. Functional outcomes assessed included conjugate formation, calcium flux, receptor regulation, cytokine production, degranulation, cytotoxicity, apoptosis induction and signal transduction. While dasatinib inhibits NK cell effector functions during functional assays, 24 hr pretreatment of NK cells followed by washout of dasatinib, led to dose-dependent enhancement of cytokine production, degranulation marker expression and cytotoxicity against selected lymphoma and leukemia cell lines. Mechanistically, this was neither due to an altered viability of NK cells nor increased NKG2D, LFA-1 or conjugate formation with target cells. Receptor proximal signaling events were inhibited. However, a slight time dependent enhancement of Vav phosphorylation was observed under certain circumstances. The shift in Vav phosphorylation level may be one major mechanism for NK cell activity enhancement induced by dasatinib. Our findings argue for a careful timing and dosing of dasatinib application during leukemia/lymphoma treatment to enhance NK cell immunotherapeutic efforts.

Comparative analysis of tumor-infiltrating lymphocytes in a syngeneic mouse model of oral cancer

OBJECTIVE

To perform a comparative analysis of infiltrating immune cells in a newly developed C57BL/6 background syngeneic transplantable mouse oral cancer (MOC) model.

STUDY DESIGN/SETTING

Scientific study in an academic medical center.

METHODS

Use of carcinogen-induced tumorigenesis, tissue culture, cell line transplantation, and flow cytometric analysis techniques.

RESULTS

Previously, the authors established a series of cell line models that displayed dichotomous growth phenotypes when transplanted into immunocompetent mice. They now show that the indolent growth pattern of the MOC1-generated tumors is associated with increased baseline and inducible major histocompatibility complex class I expression and increased CD8(+) T-cell infiltration into the tumor microenvironment. Conversely, the aggressive and metastatic pattern of MOC2-generated tumors has decreased basal and inducible class I expression and is associated with FOXP3(+)CD4(+) regulatory T-cell infiltration. Delayed primary tumor growth after targeted monoclonal antibody therapy of these FOXP3(+) regulatory cells further suggests that these immune cells contribute to the aggressive phenotype of MOC2.

CONCLUSION

These data validate that key infiltrating immune cells identified here parallel findings in human head and neck cancer, making this newly developed syngeneic model a critical platform for the continued dissection of tumor-host interactions in head and neck cancer.

CD20+ tumor-infiltrating lymphocytes have an atypical CD27- memory phenotype and together with CD8+ T cells promote favorable prognosis in ovarian cancer

PURPOSE

Tumor-infiltrating lymphocytes (TIL), in particular CD8(+) T cells and CD20(+) B cells, are strongly associated with survival in ovarian cancer and other carcinomas. Although CD8(+) TIL can mediate direct cytolytic activity against tumors, the role of CD20(+) TIL is poorly understood. Here, we investigate the possible contributions of CD20(+) TIL to humoral and cellular tumor immunity.

EXPERIMENTAL DESIGN

Tumor and serum specimens were obtained from patients with high-grade serous ovarian cancer. CD8(+) and CD20(+) TIL were analyzed by immunohistochemistry and flow cytometry. Immunoglobulin molecules were evaluated by DNA sequencing. Serum autoantibody responses to the tumor antigens p53 and NY-ESO-1 were measured by ELISA.

RESULTS

The vast majority of CD20(+) TIL were antigen experienced, as evidenced by class-switching, somatic hypermutation, and oligoclonality, yet they failed to express the canonical memory marker CD27. CD20(+) TIL showed no correlation with serum autoantibodies to p53 or NY-ESO-1. Instead, they colocalized with activated CD8(+) TIL and expressed markers of antigen presentation, including MHC class I, MHC class II, CD40, CD80, and CD86. The presence of both CD20(+) and CD8(+) TIL correlated with increased patient survival compared with CD8(+) TIL alone.

CONCLUSIONS

In high-grade serous ovarian tumors, CD20(+) TIL have an antigen-experienced but atypical CD27(-) memory B-cell phenotype. They are uncoupled from serum autoantibodies, express markers of antigen-presenting cells, and colocalize with CD8(+) T cells. We propose that the association between CD20(+) TIL and patient survival may reflect a supportive role in cytolytic immune responses.

Multifunctional immune-modulatory protein HLA-E identified in classical Hodgkin lymphoma: possible implications

Although the role of the non-classical human leukocyte antigen E (HLA-E) was originally thought to be limited to the development of a maternal tolerance to a semiallogeneic fetal graft, it is now known that HLA-E exerts multiple immunoregulatory functions. The significance of the presence of HLA-E in neoplastic cells and/or background microenvironment cells in classical Hodgkin lymphoma (cHL) is not well characterized. In our study, we evaluated the presence of HLA-E in both neoplastic and background cells in 40 cases of cHL. We found HLA-E in both neoplastic and background cells. There was a positive statistical correlation between the expression of HLA-E in neoplastic cells and the clinical stage of the disease, which indicates an immune-tolerogenic property of this multiple-purpose molecule. The presence of HLA-E in background cells seems to be prognostically neutral but its significance still needs to be determined. The mechanisms regulating the immunopathology of cHL neoplastic cells with respect to the presence of these molecule deserve further studies.

[Isolation and proteomic analysis of exosomes secreted by human cancer cells in vitro]

Exosomes are 20-100 nm membrane vesicles of endocytic origin secreted by most cell types in vitro and in vivo. Since exosomes contain both RNA (mRNA and microRNA) and proteins, which can be transferred to another cell, and be functional in that new environment, these vesicles may be involved in the communication between cells. The secretion of exosomes by tumor cells and their implication in the transport and propagation of infectious cargo suggest their participation in pathological situations. Our purpose here is to describe methods for the production, purification, and proteomic characterization of exosomes derived from human cancer cells in vitro. Based on exosomes' unique lipidic composition, we have developed the new approach to increase production of exosomes by cells in vitro. Secondly, we have developed quality control by laser correlation spectroscopy for exosomal assays based on the amount of MHC class I and CD63 molecules on their surface. At last, matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry was used after 2D electrophoresis for the proteomic analysis of exosomes derived from cancer cell lines. This study describes the protein composition of brain tumor cell-derived exosomes in more detail.

Expression of the nonclassical HLA-G and HLA-E molecules in laryngeal lesions as biomarkers of tumor invasiveness

INTRODUCTION

HLA-G and HLA-E are two nonclassical class I molecules, which have been well recognized as modulators of innate and adaptive immune responses, and the expression of these molecules in virus infected cells has been associated with subversion of the immune response.

OBJECTIVE

In this study we performed a cross-sectional study, systematically comparing the expression of HLA-G and HLA-E in benign, pre-malignant and malignant laryngeal lesions, correlating with demographic and clinical variables and with the presence of high-risk and low-risk HPV types.

MATERIALS AND METHODS

Laryngeal lesions were collected from 109 patients and stratified into 27 laryngeal papillomas, 17 dysplasias, 10 in situ laryngeal carcinomas, 27 laryngeal carcinomas without metastases, 28 laryngeal carcinomas with metastasis along with their respective draining cervical lymph nodes, and 10 normal larynx specimens. The expression of HLA-G and HLA-E molecules was determined by immunohistochemistry. HPV DNA detection and typing was performed using generic and specific primers.

RESULTS

HLA nonclassical molecules showed a distinct distribution pattern, according to the larynx lesion grade. HLA-G expression increased in benign and premalignant lesions, and gradually decreased in invasive carcinomas and in respective draining cervical lymph nodes. Conversely, HLA-E expression increased as far as lesion grade increased, including increased molecule expression in the draining lymph nodes of malignant lesions. Only 17 (15.6%) patients were HPV DNA positive.

CONCLUSIONS

Overexpression of HLA-E and underexpression of HLA-G appear to be good markers for malignant larynx lesion.

The role of MHC class I allele Mamu-A*07 during SIV(mac)239 infection

Virus-specific CD8(+) T cells play an important role in controlling HIV/SIV replication. These T cells recognize intracellular pathogen-derived peptides displayed on the cell surface by individual MHC class I molecules. In the SIV-infected rhesus macaque model, five Mamu class I alleles have been thoroughly characterized with regard to peptide binding, and a sixth was shown to be uninvolved. In this study, we describe the peptide binding of Mamu-A1*007:01 (formerly Mamu-A*07), an allele present in roughly 5.08% of Indian-origin rhesus macaques (n = 63 of 1,240). We determined a preliminary binding motif by eluting and sequencing endogenously bound ligands. Subsequently, we used a positional scanning combinatorial library and panels of single amino acid substitution analogs to further characterize peptide binding of this allele and derive a quantitative motif. Using this motif, we selected and tested 200 peptides derived from SIV(mac)239 for their capacity to bind Mamu-A1*007:01; 33 were found to bind with an affinity of 500 nM or better. We then used PBMC from SIV-infected or vaccinated but uninfected, A1*007:01-positive rhesus macaques in IFN-γ Elispot assays to screen the peptides for T-cell reactivity. In all, 11 of the peptides elicited IFN-γ(+) T-cell responses. Six represent novel A1*007:01-restricted epitopes. Furthermore, both Sanger and ultradeep pyrosequencing demonstrated the accumulation of amino acid substitutions within four of these six regions, suggestive of selective pressure on the virus by antigen-specific CD8(+) T cells. Thus, it appears that Mamu-A1*007:01 presents SIV-derived peptides to antigen-specific CD8(+) T cells and is part of the immune response to SIV(mac)239.

Down-regulation of human leukocyte antigens class I on peripheral T lymphocytes and NK cells from subjects in region of high-incidence gastrointestinal tumor

BACKGROUND

Many types of human tumors can suppress the immune system to enhance their survival. Loss or down-regulation of human leukocyte antigens (HLA) class I on tumors is considered to be a major mechanism of tumor immune escape. Our previous studies found that HLA class I on peripheral-blood mononuclear cells was significantly lower in gastric cancer patients. The present study made an analysis of HLA class I expression on peripheral-blood T lymphocytes and NK cells from subjects of Lijiadian village, a village with high-incidence gastrointestinal tumor.

METHODS

A total of 181 villagers from Lijiadian village and 153 normal controls from the Department of Health Examination Center were enrolled in this study. Using a multi-tumor markers detection system, these villagers were divided into two groups: high-risk group (tumor markers positive group) and low-risk group (tumor markers negative group). The percentage of T lymphocytes and NK cells and levels of HLA class I on their surface were determined in these subjects by flow cytometry.

RESULTS

Percentages of T lymphocytes and NK cells in peripheral-blood mononuclear cells did not vary with age. The expression level of HLA class I on peripheral T lymphocytes and NK cells was not affected by age or gender, but was significantly down-regulated in Lijiadian villagers (P < 0.05), especially on the surface of NK cells (P < 0.01). Compared with the low-risk group, there was a significant reduction of HLA class I on peripheral T lymphocytes (P < 0.05) and NK cells (P < 0.05) in the high-risk group.

CONCLUSIONS

HLA class I on peripheral T lymphocytes and NK cells may be involved in tumorigenesis and development of gastrointestinal tumor, and understanding their changes in expression may provide new insights into the mechanism of tumor immunity.

Immunostimulatory activity of dendritic cells pulsed with carbonic anhydrase IX and Acinetobacter baumannii outer membrane protein A for renal cell carcinoma

Dendritic cell (DC)-based immunotherapy is a potent therapeutic modality for treating renal cell carcinoma (RCC), but development of antigens specific for tumor-targeting and anti-tumor immunity is of great interest for clinical trials. The present study investigated the ability of DCs pulsed with a combination of carbonic anhydrase IX (CA9) as an RCC-specific biomarker and Acinetobacter baumannii outer membrane protein A (AbOmpA) as an immunoadjuvant to induce anti-tumor immunity against murine renal cell carcinoma (RENCA) in a murine model. Murine bone-marrow-derived DCs pulsed with a combination of RENCA lysates and AbOmpA were tested for their capacity to induce DC maturation and T cell responses in vitro. A combination of RENCA lysates and AbOmpA up-regulated the surface expression of co-stimulatory molecules, CD80 and CD86, and the antigen presenting molecules, major histocompatibility (MHC) class I and class II, in DCs. A combination of RENCA lysates and AbOmpA also induced interleukin-12 (IL-12) production in DCs. Next, the immunostimulatory activity of DCs pulsed with a combination of CA9 and AbOmpA was determined. A combination of CA9 and AbOmpA up-regulated the surface expression of co-stimulatory molecules and antigen presenting molecules in DCs. DCs pulsed with a combination of CA9 and AbOmpA effectively secreted IL-12 but not IL-10. These cells interacted with T cells and formed clusters. DCs pulsed with CA9 and AbOmpA elicited the secretion of interferon-γ and IL-2 in T cells. In conclusion, a combination of CA9 and AbOmpA enhanced the immunostimulatory activity of DCs, which may effectively induce anti-tumor immunity against human RCC.

[Applications of monitoring human leukocyte antigen G and its inhibitory receptors in post-renal transplantation]

OBJECTIVE

to study the feasibility of human leucocyte antigen-G (HLA-G) as a post-transplantation prognostic biomarker and discuss the correlation of its receptor expression and the mechanisms.

METHODS

a total of 215 recipients in our centre from February 2006 to June 2008 were divided into stable kidney function group (n = 173) and acute rejection group (n = 42). The soluble human leucocyte antigen-G5 (sHLA-G5) level in peripheral plasma was detected by ELISA. And the HLA-G receptor ILT-2, KIR2DL4 on T, B, NK lymphocytes were analyzed by flow cytometry (FCM). The sHLA-G5 cutoff level by ROC curve was employed to predict the events of acute post-transplantation rejection. And regression analysis was used to determine the association of sHLA-G5 with acute rejection.

RESULTS

an optimal cutoff value of 139.0 microg/L could be defined for sHLA-G5 (sensitivity: 63.6%, specificity: 82.1%, AUC: 0.780). Binary regression analysis showed that sHLA-G5 played an independent role on acute rejection (P = 0.019, OR = 0.039, 95%CI: 2.091 - 5.661). The rate of HLA-G receptor ILT-2 on CD4(+)T cell, CD8(+)T cell and B cell in acute rejection group was statistically lower than that in stable kidney function group (21% ± 7% vs 52% ± 17%, 23% ± 6% vs 39% ± 16%, 21% ± 7% vs 39% ± 16%, all P < 0.05). The expression of KIR2DL4 on NK cells in acute rejection group was statistically lower than that in stable kidney function group (31% ± 10%vs 57% ± 21%, P < 0.05).

CONCLUSION

sHLA-G5 level may be predicted for acute rejection with a high sensitivity and specificity. The up-regulated expression of ILT-2 and KIR2DLT may contribute to immunology tolerance in peripheral circulation.

Ex Vivo kinetics of early and long-term multifunctional human leukocyte antigen E-specific CD8+ cells in volunteers immunized with the Ty21a typhoid vaccine

T cells are likely to play an important role in the host defense against Salmonella enterica serovar Typhi, the causative agent of typhoid fever. We have shown that HLA-E can function as a restriction element for S. Typhi-specific CD8(+) T cells. Because of the potential importance of HLA-E-restricted CD8(+) responses in resistance to Salmonella infection, we characterized these responses and investigated their kinetics of appearance and persistence in volunteers immunized orally with the licensed attenuated Ty21a strain typhoid vaccine. Cells were obtained from volunteers before and at days 2, 4, 7, 10, 14, 28, 42, 56, 120, 180, 360, and 720 after immunization. An ex vivo multicolor staining panel including antibodies to CD107a and -b, interleukin-2, gamma interferon (IFN-gamma), and tumor necrosis factor alpha (TNF-alpha) was used to functionally assess memory T-cell subsets by flow cytometry. Increases in cytokine-secreting CD8(+) cells were observed in the T effector/memory (T(EM)) and CD45RA(+) T(EM) (T(EMRA)) subsets as early as 4 days after immunization and persisted, particularly in the T(EMRA) subset, up to 2 years after immunization. The majority of HLA-E-restricted CD8(+) cells 28 to 56 days after immunization coexpressed CD107, IFN-gamma, and TNF-alpha, showing characteristic features of multifunctional T cells. In summary, the multifunctionality and longevity of the HLA-E-restricted CD8 responses observed in this study highlight their significance in adaptive immunity to S. Typhi. Finally, this is the first demonstration, in either animals or humans, of the presence of long-term multifunctional HLA-E-restricted CD8(+) cells after immunization.

Cell bio-imaging reveals co-expression of HLA-G and HLA-E in human preimplantation embryos

The non-classical major histocompatibility complex (MHC) class Ib antigens, termed HLA-G and HLA-E, have been associated with fetal maternal tolerance. The role of HLA-G in the preimplantation embryo remains unclear although immunoprotection, adhesion and cell signalling mechanisms have been suggested. Unlike HLA-G, HLA-E protein expression has not been previously studied in preimplantation embryos. Embryos and model trophoblast cell lines JEG-3 and BeWo were labelled with the HLA-G- and HLA-E-specific monoclonal antibodies MEMG9 and MEME07. Flow cytometry, confocal microscopy and single particle fluorescence imaging techniques were employed to investigate the spatial and temporal expression of these receptors. Lipid raft analysis and adhesion assays were performed to investigate the role of these receptors in cell membrane domains and in promoting adhesion by cell-to-cell contact. HLA-E and HLA-G were co-localized in the trophectoderm of day 6 blastocysts. Analysis on trophoblast cell lines revealed that 37% of HLA-G and 41% of HLA-E receptors were co-localized as tetramers or higher order homodimer clusters. HLA-G receptors did not appear to play a role in either cell adhesion or immunoreceptor signalling via lipid raft platforms on the cell membrane. A possible role of HLA-G and HLA-E in implantation via immunoregulation or modulation of uterine maternal leukocytes is discussed.

[Immunochemical assay of MIC A production by tumor cells in vitro and in vivo as a component of antitumor vaccine development]

Due to immunological monitoring, most of aggressive tumor cells are selected capable of producing soluble factors of immunosuppression in their microenvironment. A ligand for NK- and T-cells receptor (MICA/B) activation is one of them. We investigated MICA concentrations in serum of 10 healthy volunteers and 114 patients with solid tumors (breast cancer - 24, gastrointestinal tumors - 27, renal cell carcinoma - 15, lung cancer - 9, ovarian carcinoma - 13, cutaneous melanoma - 18, primary multiple tumors - 2, prostate cancer - 6). The lowest level of MICA was reported in ovarian carcinoma (91.19 +/- 29.42 pg/ml), the highest - in rectal cancer (311.13 +/- 50.11 pg/ml) while mean concentration in healthy volunteers was (19.38 +/- 5.91 pg/ml). Cells of melanoma, renal cell carcinoma and prostate cancer became capable of producing MICA during cultivation and antitumor vaccine preparation. It is suggested that culture supernatants be tested for MICA contents as well as patients screened for vaccination. Selection of patients should be carried out on the basis of MICA molecules detection in blood flow.

The Effect of Cytokines on the Expression of Mhc Antigens and Icam-1 by Normal and Transformed Synoviocytes

We report the expression on synovial cells of cell surface molecules known to be involved in T cell activation by antigen presenting cells. Normal human synovial fibroblasts and a human synovial cell line transformed with the SV40 large T antigen were used for in vitro stimulation studies with recombinant cytokines. We demonstrate an increase in MHC-A, B, C expression in normal synovial cells in response to recombinant interferon gamma (r gamma IFN), tumour necrosis factor alpha and beta (rTNF alpha and beta) and interleukin-1 (rIL-1 alpha). Intercellular adhesion molecular-1 (ICAM-1) expression was increased in parallel with MHC Class I. The combination of r gamma IFN and rTNF alpha was additive in its effect on ICAM-1 expression. Northern blot analysis suggests that ICAM-1 expression in synovial cells is controlled at the level of transcription. In contrast, MHC Class II (HLA-DR) was only significantly induced by r gamma IFN. Other stimuli including interleukin-4 (IL-4), interleukin 6 (IL-6), granulocyte macrophage colony stimulating factor (GM-CSF) and prostaglandin E2 (PGE2) did not affect the expression of ICAM-1 or MHC Class I and II. Leucocyte function antigen 3 (LFA-3) expression was not affected by any of the stimuli tested. Immunoperoxidase staining of rheumatoid synovial tissue confirmed enhanced in vivo expression of ICAM-1 in rheumatoid arthritis. These changes are discussed in the context of T cell activation in inflammatory arthritis.

Clinical significance of the NKG2D ligands, MICA/B and ULBP2 in ovarian cancer: high expression of ULBP2 is an indicator of poor prognosis

OBJECTIVE

To investigate the clinical significance of the expression of the NKG2D ligands MICA/B and ULBP2 in ovarian cancer.

METHODS

Eighty-two ovarian cancer patients and six patients without ovarian cancer from Department of Obstetrics and Gynecology of Kyoto University Hospital were enrolled in this study between 1993 and 2003. Expression of MICA/B, ULBP2, and CD57 in ovarian cancer tissue and normal ovary tissue was evaluated by immunohistochemical staining, and the relationship of these results to relevant clinical patient data was analyzed. Expression of MICs, ULBP2, and HLA-class I molecules in 33 ovarian cancer cell lines and two normal ovarian epithelial cell lines, as well as levels of soluble MICs and ULBP2 in the culture supernatants, were measured.

RESULTS

Expression of MICA/B and ULBP2 was detected in 97.6 and 82.9% of ovarian cancer cells, respectively, whereas neither was expressed on normal ovarian epithelium. The expression of MICA/B in ovarian cancer was highly correlated with that of ULBP2. Strong expression of ULBP2 in ovarian cancer cells was correlated with less intraepithelial infiltration of T cells and bad prognoses for patients, suggesting that ULBP2 expression is a prognostic indicator in ovarian cancer. The expression of NKG2D ligands did not correlate with the levels of the soluble forms of the ligands.

CONCLUSIONS

High expression of ULBP2 is an indicator of poor prognosis in ovarian cancer and may relate to T cell dysfunction in the tumor microenvironment.

Absence of BoLA class I antigens on bovine spermatozoa

Forty AI bulls were tested for BoLA class I antigens by means of eight specific polyclonal reagents. By means of immobilization and sperm penetration tests these antigens were not detected on sperm cells. Isoimmunization studies with the use of sperm as antigenic stimuli and insemination of frozen spermatozoa diluted in specific reagents did not prove the presence of BoLA class I antigens on bovine spermatozoa. The cytotoxic tests used in this investigation were not reliable.

Multiparameter flow cytometry characterization of MHC class I negative mouse bone marrow cells

BACKGROUND

MHC-I down-regulation was described in foetal liver progenitors, and two different subsets of adult bone marrow derived stem cells. These cells, namely, MHC-I-/Thy1+ bone marrow derived liver stem cells (BMDLSC) and the multipotent adult progenitors (MAPC) differentiated into functioning hepatocytes. The aim of this paper was to characterize the MHC-I negative bone marrow compartment as it pertains to BMDLSC and MAPC.

MATERIAL/METHODS

We performed multiparameter flow-cytometry analyses of the MHC-I negative compartment using hematopoietic (CD45, Ter119), and stem cell markers (Thy1.2, c-Kit, IL-3R, CD34) in adult mice.

RESULTS

When analysing CD45 and Ter119 expression, the MHC-I negative bone marrow compartment divides into four sub-populations: 1. CD45-/Ter119+: 86.0+/-4.4%; 2. CD45+/Ter119+: 0.2+/-0.1%; 3. CD45+/Ter119-: 11.6+/-3.0%; 4. CD45-/Ter119-: 2.0+/-2.1%. Stem cells markers were only expressed on MHC-I negative/ CD45+/Ter119- cells. In vivo, MAPC (Ter119-/CD45- cells) are composed of MHC-I negative (24%) and MHC-I positive cells and do not express any of the stem cell markers tested.

CONCLUSIONS

In conclusion, mouse BMDLSC and MAPC are two distinct stem cell populations. Down-regulation of MHC-I was the only common characteristic found between BMDLSC and MAPC suggesting that selection of MHC-I negative cells might represent an efficient strategy to enrich for bone marrow stem cells with liver developmental potential.

Soluble HLA-G in the peritoneal fluid of women with endometriosis

The aim of this study was to determine the level of soluble HLA-G molecules in the peritoneal fluid of endometriosis patients. The findings demonstrate that a soluble HLA-G level in the peritoneal fluid of women with endometriosis is similar to that of the control group.

Prevalent expression of MHC class I chain-related molecule A in human osteosarcoma

MHC class I chain-related molecule A (MICA) is one of the major ligands for activating immune-receptor NKG2D which is expressed on NK cells and cytotoxic T lymphocytes. The release and sustained expression of MICA protein can impair NKG2D-mediated cytotoxic activity by reducing NKG2D receptor on immune effector cells. The aim of the study was to investigate the expression and release of MICA in human osteosarcoma. RT-PCR, immunohistochemistry, western blotting and flow cytometry were used in analyzing the expression of MICA. Serum level of soluble MICA was quantitated by ELISA. Our data showed that MICA is prevalently expressed in osteosarcoma both in mRNA and protein level. Upregulation of MICA was found in osteosarcoma compared with benign tumors and normal bone tissues. Higher level of soluble MICA in serum can be detected in osteosarcoma patients. In conclusion, prevalent expression of MICA and higher serum level of soluble MICA may suggest a deficiency of MICA-NKG2D mediated immunosurveillance in osteosarcoma patients. Restoring the expression of NKG2D receptor on immune effector cells may contribute to a therapeutic strategy for human osteosarcoma.

Decreased human leukocyte antigen–DR expression in the lipid raft by peritoneal macrophages from women with endometriosis

OBJECTIVE

To investigate the macrophage response in endometriosis by determining the expression and localization of human leukocyte antigen (HLA)-ABC and HLA-DR by the peritoneal fluid (PF) macrophages and PF concentrations of interferon (IFN)-gamma that regulate HLA expression.

DESIGN

Case-control study.

SETTING

University hospital.

PATIENT(S)

64 Japanese endometriosis patients, and 65 women with other laparoscopic diagnoses.

INTERVENTION(S)

Venipuncture and laparoscopic peritoneal fluid collection.

MAIN OUTCOME MEASURE(S)

Expression and localization of HLA-ABC and HLA-DR in PF macrophages were determined by flow cytometry and confocal microscopy. The concentration of IFN-gamma in PF was determined by enzyme-linked immunosorbent assay.

RESULT(S)

In women with endometriosis, expression of HLA-ABC and HLA-DR by PF macrophages, and the IFN-gamma concentrations in PF were statistically significantly lower than in controls. Women with endometriosis showed a statistically significant positive correlation between HLA expression and IFN-gamma concentration. By confocal microscopy, HLA-ABC was distributed homogenously on the macrophage surface whereas HLA-DR expression on these cells corresponded to the lipid raft.

CONCLUSION(S)

In women with endometriosis, low HLA expression and particularly reduced HLA-DR in the lipid raft may be influenced by low IFN-gamma and may compromise antigen presentation, limiting the immune response to peritoneal cavity antigens such as implanted or metaplastic endometrial tissue.