Major Histocompatibility Antigens Research Articles

Multiple genetic loci influence vaccine-induced protection against Mycobacterium tuberculosis in genetically diverse mice.

Mycobacterium tuberculosis (M.tb.) infection leads to over 1.5 million deaths annually, despite widespread vaccination with BCG at birth. Causes for the ongoing tuberculosis endemic are complex and include the failure of BCG to protect many against progressive pulmonary disease. Host genetics is one of the known factors implicated in susceptibility to primary tuberculosis, but less is known about the role that host genetics plays in controlling host responses to vaccination against M.tb. Here, we addressed this gap by utilizing Diversity Outbred (DO) mice as a small animal model to query genetic drivers of vaccine-induced protection against M.tb. DO mice are a highly genetically and phenotypically diverse outbred population that is well suited for fine genetic mapping. Similar to outcomes in people, our previous studies demonstrated that DO mice have a wide range of disease outcomes following BCG vaccination and M.tb. challenge. In the current study, we used a large population of BCG-vaccinated/M.tb.-challenged mice to perform quantitative trait loci mapping of complex infection traits; these included lung and spleen M.tb. burdens, as well as lung cytokines measured at necropsy. We found sixteen chromosomal loci associated with complex infection traits and cytokine production. QTL associated with bacterial burdens included a region encoding major histocompatibility antigens that are known to affect susceptibility to tuberculosis, supporting validity of the approach. Most of the other QTL represent novel associations with immune responses to M.tb. and novel pathways of cytokine regulation. Most importantly, we discovered that protection induced by BCG is a multigenic trait, in which genetic loci harboring functionally-distinct candidate genes influence different aspects of immune responses that are crucial collectively for successful protection. These data provide exciting new avenues to explore and exploit in developing new vaccines against M.tb.

Transcriptomic analysis reveals the potential crosstalk genes and immune relationship between Crohn's disease and atrial fibrillation.

At present, there is a paucity of research on the link between Crohn's disease (CD) and atrial fibrillation (AF). Nevertheless, both ailments are thought to entail inflammatory and autoimmune processes, and emerging evidence indicates that individuals with CD may face an elevated risk of AF. To shed light on this issue, our study seeks to explore the possibility of shared genes, pathways, and immune cells between these two conditions. We retrieved the gene expression profiles of both CD and AF from the Gene Expression Omnibus (GEO) database and subjected them to analysis. Afterward, we utilized the weighted gene co-expression network analysis (WGCNA) to identify shared genes, which were then subjected to further Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. Furthermore, we employed a rigorous analytical approach by screening hub genes through both least absolute shrinkage and selection operator (LASSO) regression and support vector machine (SVM), and subsequently constructing a receiver operating characteristic (ROC) curve based on the screening outcomes. Finally, we utilized single-sample gene set enrichment analysis (ssGSEA) to comprehensively evaluate the levels of infiltration of 28 immune cells within the expression profile and their potential association with the shared hub genes. Using the WGCNA method, we identified 30 genes that appear to be involved in the pathological progression of both AF and CD. Through GO enrichment analysis on the key gene modules derived from WGCNA, we observed a significant enrichment of pathways related to major histocompatibility complex (MHC) and antigen processing. By leveraging the intersection of LASSO and SVM algorithms, we were able to pinpoint two overlapping genes, namely CXCL16 and HLA-DPB1. Additionally, we evaluated the infiltration of immune cells and observed the upregulation of CD4+ and CD8+ T cells, as well as dendritic cells in patients with AF and CD. By employing bioinformatics tools, we conducted an investigation with the objective of elucidating the genetic foundations that connect AF and CD. This study culminated in the identification of CXCL16 and HLA-DPB1 as the most substantial genes implicated in the development of both disorders. Our findings suggest that the immune responses mediated by CD4+ and CD8+ T cells, along with dendritic cells, may hold a crucial role in the intricate interplay between AF and CD.

Effect of interleukin-2 (IL-2) polymorphisms on multiple myeloma: IL-2RA rs2104286, IL-2 rs2069762 and rs2069763 polymorphisms

Interleukin-2 (IL-2) is a cytokine secreted from T helper type 1 cells and released after induction of T helper cells with major histocompatibility complexes or antigens presented by antigen presenting cells. IL-2 activity and gene polymorphisms have been studied in both solid and hematological malignancies. In the present study, it was aimed to examine the effects of IL-2RA rs2104286, IL-2 rs2069762 and rs2069763 polymorphisms on multiple myeloma (MM) susceptibility, progression-free survival (PFS) and overall survival (OS). A total of 300 patients diagnosed with MM in our clinic between January 2010 and January 2021, and 170 healthy individuals were included. In addition to the demographic data of the patients, MM subtypes, initial stages, prognostic index scores, laboratory results, treatment preferences, and survival data were recorded. The genotypes of the IL-2RA rs2104286, IL-2 rs2069762 and rs2069763 polymorphisms were statistically compared between patients and healthy controls to reveal their effects on MM susceptibility and survival. In the statistical analysis performed to examine the effect of IL-2RA rs2104286, IL-2 rs2069762 and rs2069763 polymorphisms on disease susceptibility, no significant difference was found between the patient and healthy control groups. Patients with the TG genotype of IL-2 rs2069762 had a significantly shorter median PFS and OS compared to others. Patients with the GG genotype of IL-2 rs2069763 had a significantly shorter median PFS compared to others. Having the TG genotype of IL-2 rs2069762 has been shown to be protective for short PFS and OS. Our study results will be guiding in terms of IL-2 based therapies, the future for MM and MM epigenetics.

Abstract B034: A scoping review of carcinogenic potential in prostate cancer from 40+ years of functional vitamin D and K deficiency

Abstract Introduction: Carcinogenesis is a form of accelerated genetic “Darwinian” evolution. Many cells start genetic change. Tobacco tar, an example of extensively researched carcinogen, demonstrates that it takes chronic exposure over 40+ years, accumulating mutations before death with multiple genetic events. Terminal acceleration often includes loss of major histocompatibility (MHC) antigens. Other co-carcinogens, genetic inheritance and chronic inflammation accelerates this process. Experiments, showing that malignant change induced in vitro is much faster than in vivo, suggest that other factors impact on the pace of malignant evolution. Two such factors (DNA repair and immune surveillance) are the best established. As considerable research is targeting DNA repair gene damage, this abstract focuses on latent immunity (less dependent on MHC system than T cell immunity) and its under-performance in carcinogenesis due to Vitamin D and K deficiency. Literature Review terms: Vitamin D(VD), Vitamin K(VK), Cancer, Carcinogenesis, Latent Immunity. Results: Three pieces of evidence that functional long-term VD and VK deficiency could have oncogenic potential were identified. The first was discovery that patients with chronic inflammation had hypermethylation of the VD receptor resulting in failure of the liver to convert stored VD into its active forms. Cancer patients with higher extent of methylation of VD receptor had worse clinical outcomes. Such deficiency is associated with reduced innate immunity due to macrophage dysfunction and this deficiency could increase microbiome dysbiosis. This suggestion is supported by studies linking PCa with 40+ years of persistent infection with the sun-sensitive microaerophilic bacterium Cutibacterium acnes and VD deficiency is linked with increased cancer but limited benefits in VD trials. The second observation is the demonstration that VK2 (Menaquinone) not VK1 (Phylloquinone) deficiency increased risk of PCa. These authors also showed that undercarboxylated osteocalcin, a biomarker of VK2 deficiency, was also linked with risk of PCa. The third observation was evidence from in-vitro breast cancer cell-line studies that Calcitriol plus K2 was synergistic in cytotoxicity assays. Measuring these effects, through the study of the biological age using methylation-based measures PhenoAge and GrimAge because of their relationship between biological aging and cancer, could be useful to monitor in future trials. Conclusions: Combined VD and VK studies have been found safe and beneficial in bone health. This limited review justifies further exploration of this combination in cancer patients. Using serial epigenetic clock scores is justified, given that these clocks are known to improve from diet and exercise interventions. Functional deficiency of VD and VK could be acting as co-carcinogens through enhanced inflammatory process, a precursor in many cancers including those without known carcinogen involvement such as PCa and also involved in accelerating tumour growth after primary treatment. Citation Format: Tim R.D. Oliver, Belinda Nedjai. A scoping review of carcinogenic potential in prostate cancer from 40+ years of functional vitamin D and K deficiency [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr B034.

Cell-based therapy in prophylaxis and treatment of chronic graft-versus-host disease.

Hematopoietic allogeneic stem cell transplantation (allo-SCT) is a curative option for patients with hematological malignancies. However, due to disparities in major and minor histocompatibility antigens between donor and recipient, severe inflammatory complications can occur, among which chronic graft-versus-host disease (cGVHD) can be life-threatening. A classical therapeutic approach to the prevention and treatment of cGVHD has been broad immunosuppression, but more recently adjuvant immunotherapies have been tested. This review summarizes and discusses immunomodulatory approaches with T cells, including chimeric antigen receptor (CAR) and regulatory T cells, with natural killer (NK) cells and innate lymphoid cells (ILCs), and finally with mesenchymal stromal cells (MSC) and extracellular vesicles thereof. Clinical studies and pre-clinical research results are presented likewise.

The Potential Clinical Application of Induced Tolerogenic Macrophages.

The Potential Clinical Application of Induced Tolerogenic Macrophages.

Kinetics of immune activated T cells in aplastic anemia mouse model

目的探索再生障碍性贫血（AA）小鼠模型中供者来源T细胞不同时间点动力学变化。方法构建AA小鼠模型，分别于不同时间点采用流式细胞术测定模型小鼠脾脏与骨髓内供者T细胞比例、活化分子表达、细胞周期及功能亚群，评估不同时期T细胞功能状态。结果①半致死剂量照射联合主要组织相容性抗原（MHC）半相合的淋巴结细胞输注成功构建T细胞免疫介导的AA小鼠模型。②AA小鼠脾脏中供者T细胞从移植第3天后开始明显浸润，并逐渐出现CD4+/CD8+比例倒置，第5天开始进入骨髓，以CD8+细胞浸润为主。③CD69在供者CD4+细胞中表达高峰晚于CD8+细胞，CD25在CD4+细胞与CD8+细胞中表达水平的变化趋势相同，但在CD8+细胞中的表达高于CD4+细胞。④脾脏内供者CD4+细胞S/G2/M期比例在移植后第3天即达高峰，约12％，而CD8+细胞中S/G2/M期比例在移植后第5天达高峰，约20％，且两者在进入骨髓后S/G2/M期比例均再次升高，但移植第3天后其比例在脾脏与骨髓CD8+细胞中持续高于CD4+细胞。⑤脾脏内免疫活化的T细胞经历短暂的中枢记忆T细胞（TCM）阶段后迅速分化为效应记忆T细胞（TEM），进入骨髓后部分TEM分化为效应细胞进一步发挥效应功能。结论AA小鼠模型中供者T细胞进入异体后迅速活化，5天内达增殖高峰，并完成向TEM细胞的分化，5天后开始进入骨髓进一步增殖损伤造血。

Abstract 2740: Stochastic modeling uncovers the interplay between early cancer progression and adaptive immune-specific cancer escape

Abstract The lack of durable therapeutic interventions continues to limit cancer treatment efficacy. While breakthroughs in immunotherapy have improved patient survival for some disease subtypes, immune escape is an unfortunate and common hallmark of cancer evasion. Understanding the dynamic interplay between an evolving and heterogeneous malignant population and the adaptive immune system, consisting of millions of unique T cells, is therefore required for designing optimized treatment strategies. We begin by describing the implications of cancer escape via durable evasion events, such as major histocompatibility antigen presentation down-regulation. Durable escape is then applied to relate observed cancer age-specific incidence to physiologic impairments in T cell turnover and diversity. We then discuss a more generalized stochastic process that enables transient escape and recurrent recognition via distinct T cell subclones. This co-evolutionary model predicts repeated immune recognition and cancer evasion prior to disease manifestation. Using this model, we find that T cell turnover and cancer mutation rates explain differences in early age incidence data across nearly all cancer types. Lastly, we introduce a modeling approach for understanding the extent of optimality occurring in cancer evasion via tumor-associated antigen downregulation, emphasizing the utility of foundational modeling frameworks for optimizing cancer T cell immunotherapy. Citation Format: Jason T. George. Stochastic modeling uncovers the interplay between early cancer progression and adaptive immune-specific cancer escape [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2740.

Fetal‐placental antigens and the maternal immune system: Reproductive immunology comes of age*

Reproductive physiology and immunology as scientific disciplines each have rich, largely independent histories. The physicians and philosophers of ancient Greece made remarkable observations and inferences to explain regeneration as well as illness and immunity. The scientific enlightenment of the renaissance and the technological advances of the past century have led to the explosion of knowledge that we are experiencing today. Breakthroughs in transplantation, immunology, and reproduction eventually culminated with Medawar’s discovery of acquired immunological tolerance, which helped to explain the transplantation success and failure. Medawar’s musings also keenly pointed out that the fetus apparently breaks these newly discovered rules, and with this, the field of reproductive immunology was launched. As a result of having stemmed from transplantation immunology, scientist still analogizes the fetus to a successful allograft. Although we now know of the fundamental differences between the two, this analogy remains a useful tool to understand how the fetus thrives despite its immunological disparity with the mother. Here, we review the history of reproductive immunology, and how major and minor histocompatibility antigens, blood group antigens, and tissue‐specific “self” antigens from the fetus and transplanted organs parallel and differ.

NK Cells in Protection from HIV Infection.

Some people, known as HIV-exposed seronegative (HESN) individuals, remain uninfected despite high levels of exposure to HIV. Understanding the mechanisms underlying their apparent resistance to HIV infection may inform strategies designed to protect against HIV infection. Natural Killer (NK) cells are innate immune cells whose activation state depends on the integration of activating and inhibitory signals arising from cell surface receptors interacting with their ligands on neighboring cells. Inhibitory NK cell receptors use a subset of major histocompatibility (MHC) class I antigens as ligands. This interaction educates NK cells, priming them to respond to cells with reduced MHC class I antigen expression levels as occurs on HIV-infected cells. NK cells can interact with both autologous HIV-infected cells and allogeneic cells bearing MHC antigens seen as non self by educated NK cells. NK cells are rapidly activated upon interacting with HIV-infected or allogenic cells to elicit anti-viral activity that blocks HIV spread to new target cells, suppresses HIV replication, and kills HIV-infected cells before HIV reservoirs can be seeded and infection can be established. In this manuscript, we will review the epidemiological and functional evidence for a role for NK cells in protection from HIV infection.

Modeling acute graft-versus-host disease (aGVHD) in murine bone marrow transplantation (BMT) models with MHC disparity.

For more than 50years, hematopoietic stem cell transplantation (HSCT) has been the major curative therapy for hematological malignancies and genetic disorders, but its success is limited by the development of graft-versus-host disease (GVHD). GVHD represents a post-transplantation disorder representing the immune-mediated attack of transplant-derived T cells against recipient tissue finally leading to increased morbidity and mortality of the recipient. GVHD develops if donor and recipient are disparate in major or minor histocompatibility antigens (MHC, miHA). Most of the initial knowledge about the biology of GVHD is derived from murine bone marrow transplantation (BMT) models. Of course, GVHD mouse models do not reflect one to one the human situation, but they contribute significantly to our understanding how conditioning and danger signals activate the immune system, enlighten the role of individual molecules, e.g., cytokines, chemokines, death-inducing ligands, define the function of lymphocytes subpopulations for GVHD development and have significant impact on establishing new treatment and prevention strategies used in clinical HSCT. This chapter describes in detail the procedure of allogeneic BMT and the development of GVHD in two commonly used allogeneic murine BMT models (B6→B6.bm1, B6→B6D2F1) with different MHC disparities, which can be used as a basis for advanced studies of GVHD pathology or the development of new treatment strategies.

Abstract 10279: Altered Myocardial Gene Expression in H2-kbm1 Mice with Orexinergic Dysfunction and Heart Failure

Introduction: Mice carrying a homozygous frameshift mutation of the class I major histocompatibility antigen H2-K1 (H2-Kbm1) exhibit impaired development of hypothalamic orexinergic neurons. Similar to mice lacking the hypocretin (orexin) 2 receptor, H2-Kbm1 mice develop dilated cardiomyopathy and systolic heart failure (HF) from an early age. Previous studies suggest response to orexinergic signaling is predictive of patient response to current HF pharmacotherapeutic regimes. Our goal was to characterize the myocardial gene expression profiles of H2-Kbm1 mice. Methods: RNA was isolated from mice hearts (wild type n=5, mutant n=7) via the Qiagen RNeasy Mini Kit. DNase treatment was done to limit contamination of genomic DNA. Gene expression was measured using Illumina nexteq500 and 550 sequencing systems from a DNA library generated via the NuGene library kit (10 ng RNA). RNA-seq data analyses including comparisons, volcano and heatmap plots were completed. Results: H2-Kbm1 mice differentially express 398 myocardial genes compared to control mice. Ingenuity pathway analysis indicates that these genes are involved in necrosis of cardiac muscle (z-score -1.8), cell death (z-score 1.6), and cardiac contractility (z-score -4). Upstream signaling analysis suggest regulation by Mir-122 (z-score 2.4), DNMT3 A and B (z-score 3.3 and 2.5), VEGF (z-score 4.6) and rosiglitazone (z-score -6.8). Canonical pathway analysis is shown in Figure 1. Conclusion: H2-Kbm1 mice develop heart failure with marked myocardial transcriptional abnormalities that lead to impaired cardiac contraction and cell death. Differentially expressed genes are predominantly involved in mitochondrial function, oxidative phosphorylation, sirtuin signaling and the TCA cycle. Regulation of these genes is associated with miR-122, DNA methylations by DNMT3 A & B, VEGF and rosiglitazone signaling. The orexin pathway is a potential target for heart failure therapeutics.

Donor Lymphocyte Infusion Is a Feasible Way to Improve Survival in Patients with Acute Myeloid Leukemia and Myelodysplastic Syndromes Who Relapse after Allogeneic Stem Cell Transplantation

Introduction: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a curative treatment in patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS) yet the major cause of death remains relapse after transplantation which occurs in 30-70% of patients for whom the prognosis is dismal. Since the 1990's donor lymphocyte infusion (DLI) has been proven able to induce remission after allo-HSCT and the use of therapeutic DLI at relapse has widely increased. The immunological mechanism in DLI is primarily T-cell-mediated graft-versus-leukemia (GVL) effect driven by genetic differences between donor and recipient in minor and major histocompatibility antigens. DLI treatment at relapse can additionally reverse T-cell exhaustion and increase T-cell receptor diversity, both of which are GVL-enhancing mechanisms. Risks and complications with DLI-treatment are primarily graft-versus-host disease (GVHD). Though dose escalation schedules have been suggested to increase the GVL-effect while minimizing the risk of GVHD, uniform therapeutic algorithms are still lacking, treatment is often individually scheduled, and outcome results are often disappointing with reported 2-year overall survival rates at 14-29% in AML relapse patients (Greiner J, Götz M, Bunjes D, Hofmann S, Wais V. Immunological and Clinical Impact of Manipulated and Unmanipulated DLI after Allogeneic Stem Cell Transplantation of AML Patients. J Clin Med. 2019;9(1):39). During the last decade, treatment with the hypomethylating agent azacitidin (Aza) has become another potential treatment in patients with myeloid malignancies. Immunological mechanisms of GVL in Aza-treatment for relapse include epigenetically reactivation of pro-apoptotic pathways and demasking of tumor-antigens while increased expression of regulatory T-cells protects from GVHD. In recent years DLI and Aza have been used for synergistical effect post-HSCT relapse both in patients who are un-fit to receive high-dose cytoreductive therapy as well as consolidation after reinduction. The aim of this analysis is to report results of retrospective single center-study of patients treated with DLI +/- Aza over a period of twenty years.Methods: Between 2001 and 2020 50 adult patients with relapse after allo-HSCT for AML(n=38) or MDS (n=12) were treated with DLI at the Department of Hematology, Transplant Unit, at Rigshospitalet, Copenhagen University Hospital, table 1. Only patients free from active GVHD were selected as DLI-candidates. Median follow-up time was 57 (1-170) months. Reinduction with high-dose chemotherapy was administered in 35 (70%) of patients prior to DLI and 34 (68%) patients were in complete morphological remission (CR) before DLI. DLI-products were unmanipulated and obtained from leukapheresis of unstimulated peripheral blood in matched related or unrelated donors of the original stem cell graft. Patients received a median of 3 (1-5) doses of DLI with median total doses of 6,1x10 7 (5x10 6- 4,65x10 8) CD3 postive T-cells per kg. Aza was used together with DLI from 2012 and administrered in 28 (56%) patients with a median of 6 (2-20) cycles. Reported outcomes are overall survial (OS) and relapse-free survival (RFS) in patients in CR prior to DLI.Results: At end of follow-up 20 patients were alive, 11 of these in CR and 2 in partial remission. In 7 patients, DLI was discontinued due to the development of GVHD after 1-2 doses, 6/7 of these patients had unrelated donors. Overall, 2 (4%) patients died from GVHD after DLI. Seven patients received a second HSCT after DLI treatment and were censored at this date in survival analyses. Figure 1a+b shows OS in all patients (n=50) and RFS in patients in CR prior to DLI (n=34). 2-year OS was approximately 59% and 5-year OS was 20%. 2-year RFS was approximately 32% and 5-year RFS was 8%. None of the analyzed baseline factors showed significant associations to the probability of OS, table 2, or RFS (data not shown). Reinduktion before first DLI and increasing doses of transplanted CD3 T cell per kg showed trends towards superior survival probability but failed to reach significant levels, possibly due to the limited patient number.Conclusion: Treatment vith DLI +/- Aza is effective and safe as relapse-treatment after allo-HSCT in myeloid diseases. In selected patients, a short-term (2-year) overall survival of 59% is achieved, and 20% of the patients remain long term survivors. [Display omitted] DisclosuresFischer-Nielsen: A.F.N. is employee and shareholder of StemMedical A/S, a biotech company working with cell-enriched fat grafting.: Current Employment, Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company.

Extended survival versus accelerated rejection of nonhuman primate islet allografts: Effect of mesenchymal stem cell source and timing

Mesenchymal stem cells (MSC) have been shown to be immunomodulatory, tissue regenerative, and graft promoting; however, several questions remain with regard to ideal MSC source and timing of administration. In this study, we utilized a rigorous preclinical model of allogeneic islet cell transplantation, incorporating reduced immune suppression and near to complete mismatch of major histocompatibility antigens between the diabetic cynomolgus monkey recipient and the islet donor, to evaluate both the graft promoting impact of MSC source, that is, derived from the islet recipient, the islet donor or an unrelated third party as well as the impact of timing. Co-transplant of MSC and islets on post-operative day 0, followed by additional IV MSC infusions in the first posttransplant month, resulted in prolongation of rejection free and overall islet survival and superior metabolic control for animals treated with recipient as compared to donor or third-party MSC. Immunological analyses demonstrated that infusion of MSC from either source did not prevent alloantibody formation to the islet or MSC donor; however, treatment with recipient MSC resulted in significant downregulation of memory T cells, decreased anti-donor T cell proliferation, and a trend toward increased Tregulatory:Tconventional ratios.

Identification and Mitigation of Defensins in the Immunopurification of Peptide MHC-I Antigens from Lung Tissue.

The class I major histocompatibility (MHC-I) complex is a set of diverse cell surface receptors encoded by the human leukocyte antigen gene complex. These receptors present intracellular antigens to cytotoxic T cells providing information on the state and health of cells. Changes in the immunopeptidome during cancer may provide novel targets for therapeutic intervention. To understand how the tumor immunopeptidome is altered, we developed a mass spectrometry (MS) based platform for isolating and identifying MHC-I peptide antigens in lung tumors. In the course of our work, we encountered several large unknown peptide contaminants which had not been previously reported. To understand the source of these major contaminants, we isolated them using offline fractionation and identified them by liquid chromatography-tandem mass spectrometry (LC-MS/MS) as members of the host defense protein family known as the defensins. To mitigate their detrimental effects, we modified our "Original" data-dependent acquisition (DDA) MS method to narrowly target the MHC-I peptides based on their physical properties including charge state and molecular weight ("z state" DDA), evaluated field asymmetric ion mobility spectrometry to attempt gas-phase separation prior to MS analysis, and developed an immunodepletion approach using defensin specific antibodies. This modified approach improves peptide identification and reduces the impact of defensin contamination in lung tissue samples.

Antibody Responses to Minor Histocompatibility Antigens After Solid Organ Transplantation.

Antibody-mediated rejection (AMR) is a major barrier to long-term graft survival following solid organ transplantation (SOT). Major histocompatibility antigens mismatched between donor and recipient are well-recognized targets of humoral alloimmunity in SOT and thought to drive most cases of AMR. In contrast, the implication of minor histocompatibility antigens (mHAs) in AMR has not been fully investigated, and their clinical relevance remains controversial. Recent technological advances, allowing for genome-wide comparisons between donors and recipients, have uncovered novel, polymorphic mHA targets with potential influence on the graft outcome following SOT. Here, we review these latest studies relating to mHAs and discuss their clinical significance.

Post-Transplantation Cyclophosphamide Induces Alloreactive T-Cell Functional Impairment and Depends on Foxp3+ Regulatory T Cells Not Selective Elimination or Intrathymic Clonal Deletion of Alloreactive T Cells

Our understanding of how post-transplantation cyclophosphamide (PTCy) prevents graft-versus-host disease (GVHD) in hematopoietic cell transplantation (HCT) is largely extrapolated from major histocompatibility complex (MHC)-matched murine skin allografting models. This current paradigm of understanding posits that PTCy preferentially eliminates alloreactive T cells and is also dependent on intrathymic clonal deletion of alloreactive T cells. Skin allografting data used to generate this model leveraged strain-specific differential expression of certain T-cell receptor (TCR) Vβs as markers of alloreactive cells.To test the hypothesis that PTCy works via selective elimination of alloreactive T cells and investigate the biology of PTCy, we developed a murine MHC-haploidentical HCT model that directly parallels human sibling haploidentical HCT. In this model (B6C3F1→B6D2F1), the administration of 40 x 106 splenocytes and 10 x 106 T-cell-depleted bone marrow cells following 10.5 Gy irradiation induced universally fatal GVHD, with the Vβ6 TCR serving as a marker of alloreactive T cells. Administration of PTCy on days +3 and +4 at doses ranging from 10 to 50 mg/kg effectively prevented lethal GVHD.In assessments of the blood, lymph nodes, spleen, and liver, PTCy 25 mg/kg did reduce proliferation of CD4+ T cells but not CD8+ T cells at day +7 post-transplant. Vβ6+ T cells in both the CD4+ and CD8+ subsets in all four tissue compartments persisted at or above normal donor frequencies at days +7, +21, and +200 post-transplant. Persistence of Vβ6+ T cells in all four tissue compartments also was demonstrated in three other murine HCT models: B6→B6D2F1 (MHC-haploidentical; day +7), C3H→B6D2F1 (MHC-disparate; days +6 and +200), and C3H→AKR (MHC-matched; day +7). Using our B6C3F1→B6D2F1 model, we also created grafts in which 8% of donor CD8+ T cells expressed the 2C TCR, which is specific for H2-Ld (a major histocompatibility antigen in our model). 2C TCR+ T cells continued to proliferate highly and markedly expand from days +3 to +7 despite administration of PTCy 25 mg/kg on days +3 and +4, disproving selective alloreactive T-cell elimination after PTCy treatment in HCT. Additionally, PTCy was equally effective in our wild-type B6C3F1→B6D2F1 model when using thymectomized or non-thymectomized recipients, negating a necessary role for the thymus in GVHD prevention by PTCy.Compartmentalization could not explain GVHD amelioration despite persistence of alloreactive T cells as similarly normal Vβ6+ frequencies were found infiltrating the liver, a GVHD target organ, as were found in the blood, lymph nodes, or spleen. Indeed, 2C TCR+ T cells composed 70-80% of liver-infiltrating CD8+ T cells at day +7 in mice treated with or without PTCy. Yet, compared with vehicle-treated mice, liver-infiltrating wild-type T cells obtained at day +21 from PTCy-treated mice had slightly reduced proliferation but dramatically lower cytokine production when restimulated in vitro with DBA/2 (host parental) irradiated splenocytes. Similar results were seen when repeating these experiments using liver-infiltrating T cells that were flow cytometrically depleted of CD4+CD25+ T cells, suggesting impaired functionality of alloreactive T cells after PTCy.CD4+CD25+Foxp3+ T cells did preferentially expand in all four tissue compartments by day +21 post-transplant. A one-log reduction of these cells in the donor graft using an AutoMACS had minimal impact on transplant outcomes in our model. However, a two-log reduction of Foxp3+ cells immediately post-transplant in vivo using Foxp3-DTR-expressing donor cells resulted in marked worsening of the clinical scores and weights, which began to diverge starting approximately 30 days post-transplant. PTCy-treated mice also were resistant to reinfusion of 40 or 120 x 106 new donor splenocytes at +120-150 days, consistent with suppression being an active mechanism underlying PTCy's efficacy. Overall, our findings disprove the existing paradigm of understanding of how PTCy prevents GVHD, support our previously demonstrated role for regulatory T cells, and may have direct translational relevance towards improving outcomes for patients. DisclosuresNo relevant conflicts of interest to declare.

Immunomodulatory Responses Of Toll Like Receptors Against 2019nCoV

The present review discusses the immune signals via toll like receptors (TLRs) against 2019nCoV. We researched using different database, up to June 18th, 2020. All the included articles were published in English language. The outcome of this review, that some TLRs agonists or antagonists are progressed as drugs to combat and down regulating TLRs immune signals respectively. TLRs 3 and 4 recognized 2019nCoV spike protein through immune and molecular signals that leading to immune stimulation of pro-inflammatory cytokines and even the immune fever. While the TLRs7 and 8 recognized single-stranded ribonucleic acids (ssRNAs) leading to elevation of the tumour necrosis factor α (TNF-α), interleukin (IL)-6 and -12 levels. TLRs agonists or antagonists utilized as immunotherapeutic targets against 2019nCoV via TLRs signals. Chloroquine and hydroxychloroquine; the approval compounds for 2019nCoV therapy can be inhibiting the class II major histocompatibility complex molecules expression and antigen presentation and even immune suppressions of the pro-inflammatory cytokines profile.

CD8 Co-Receptor Enhances T-Cell Activation without Any Effect on Initial Attachment.

The scanning of surrounding tissues by T lymphocytes to detect cognate antigens requires high speed, sensitivity and specificity. T-cell receptor (TCR) co-receptors such as CD8 increase detection performance, but the exact mechanism remains incompletely understood. Here, we used a laminar flow chamber to measure at the single molecule level the kinetics of bond formation and rupture between TCR- transfected CD8+ and CD8− Jurkat cells and surfaces coated with five peptide-exposing major histocompatibility antigens (pMHCs) of varying activating power. We also used interference reflection microscopy to image the spreading of these cells dropped on pMHC-exposing surfaces. CD8 did not influence the TCR–pMHC interaction during the first few seconds following cell surface encounter, but it promoted the subsequent spreading responses, suggesting that CD8 was involved in early activation rather than binding. Further, the rate and extent of spreading, but not the lag between contact and spreading initiation, depended on the pMHC. Elucidating T-lymphocyte detection strategy may help unravel underlying signaling networks.

RETRACTED ARTICLE: A biomimetic assay platform for the interrogation of antigen-dependent anti-tumor T-cell function

Overcoming tumor-mediated immunosuppression and enhancing cytotoxic T-cell activity within the tumor microenvironment are two central goals of immuno-oncology (IO) drug discovery initiatives. However, exploratory assays involving immune components are often plagued by low-throughput and poor clinical relevance. Here we present an innovative ultra-high-content assay platform for interrogating T-cell-mediated killing of 3D multicellular tumor spheroids. Employing this assay platform in a chemical genomics screen of 1800 annotated compounds enabled identification of small molecule perturbagens capable of enhancing cytotoxic CD8+ T-cell activity in an antigen-dependent manner. Specifically, cyclin-dependent kinase (CDK) and bromodomain (BRD) protein inhibitors were shown to significantly augment anti-tumor T-cell function by increasing cytolytic granule and type II interferon secretion in T-cells in addition to upregulating major histocompatibility complex (MHC) expression and antigen presentation in tumor cells. The described biotechnology screening platform yields multi-parametric, clinically-relevant data and can be employed kinetically for the discovery of first-in-class IO therapeutic agents.