Types Of Antigen-presenting Cells Research Articles

Abstract 7477: Isoxanthohumol inhibits LPS-induced inflammatory responses in macrophages

Abstract Background: Pathogen infection, such as bacteria, viruses, and fungus, frequently leads to septicemia through a series of inflammatory responses that have very high fatality rates. And, servere inflammation may cause gene mutation which is beginning of cancer. Macrophages are a critical type of antigen-presenting cells that control both innate and adaptive immune responses. During pathogen infection, activated macrophages secret many proinflammatory mediators and cytokines, including nitric oxide (NO), TNF-α and IL-6 against pathogens; however, an overwhelming inflammatory response provokes abundant cells to undergo apoptosis. In the present study, we aimed to examine the anti-inflammatory effect of isoxanthohumol, a prenylflavonoid from hops and beer. Method: We used lipopolysaccharide (LPS) as a pathogenic stimulus to induce inflammatory responses by J774A.1 macrophages. MTT assay was used to detect cell viability. The secretion of NO was analyzed by Griess reagent assay, while the production of TNF-α, IL-6, IL-1β was measured by enzyme-linked immunosorbent assay (ELISA). The expression of iNOS, COX-2, and MAPKs was examined by Western blotting. The activity of NF-κB was analyzed by promotor reporter assay. The activation of NLRP3 inflammasome was examined by ELISA and immunofluorescence staining. In addition to that, we explored the secretion of cytokines, IL-1β, in THP-1 cell. Result: We found that isoxanthohumol significantly suppresses the secretion of NO and attenuates the production of TNF-α and IL-6 by LPS-induced macrophages. In addition, isoxanthohumol also inhibits the expression of iNOS and COX-2, suppresses the phosphorylation of JNK, and attenuates the activity of NF-κB by LPS-induced macrophages. Moreover, isoxanthohumol decreases the activation of NLRP3 inflammasome by reducing the production of IL-1β and repressing the ASC speck formation of NLRP3 inflammasome in LPS/ATP-induced macrophages. Conclusion: Our experimental results demonstrated that isoxanthohumol effectively inhibits LPS-induced inflammatory responses in macrophages, suggesting that isoxanthohumol might have benefits for attenuating inflammation. Citation Format: Tzu-Han Kao, Chia-yang Li. Isoxanthohumol inhibits LPS-induced inflammatory responses in macrophages [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7477.

Unnatural lipids for simultaneous mRNA delivery and metabolic cell labeling.

Lipids have demonstrated tremendous promise for mRNA delivery, as evidenced by the success of Covid-19 mRNA vaccines. However, existing lipids are mostly used as delivery vehicles and lack the ability to monitor and further modulate the target cells. Here, for the first time, we report a class of unnatural lipids (azido-DOTAP) that can efficiently deliver mRNAs into cells and meanwhile metabolically label cells with unique chemical tags (e.g., azido groups). The azido tags expressed on the cell membrane enable the monitoring of transfected cells, and can mediate subsequent conjugation of cargos via efficient click chemistry for further modulation of transfected cells. We further demonstrate that the dual-functional unnatural lipid is applicable to different types of cells including dendritic cells, the prominent type of antigen presenting cells, potentially opening a new avenue to developing enhanced mRNA vaccines.

Tissue-specific antigen-presenting cells contribute to distinct phenotypes of allergy.

Antigen-presenting cells (APCs) are critical cells bridging innate and adaptive immune responses by taking up, processing, and presenting antigens to naïve T cells. At steady state, APCs thus control both tissue homeostasis and the induction of tolerance. In allergies however, APCs drive a Th2-biased immune response that is directed against otherwise harmless antigens from the environment. The main types of APCs involved in the induction of allergy are dendritic cells, monocytes, and macrophages. However, these cell types can be further divided into local, tissue-specific populations that differ in their phenotype, migratory capacity, T-cell activating potential, and production of effector molecules. Understanding if distinct populations of APCs contribute to either tissue-specific immune tolerance, allergen sensitization, or allergic inflammation will allow us to better understand disease pathology and develop targeted treatment options for different stages of allergic disease. Therefore, this review describes the main characteristics, phenotypes, and effector molecules of the APCs involved in the induction of allergen-specific Th2 responses in affected barrier sites, such as the skin, nose, lung, and gastrointestinal tract. Furthermore, we highlight open questions that remain to be addressed to fully understand the contribution of different APCs to allergic disease.

The potential role of infusions of T regulatory cells in inducing and maintaining liver allograft tolerance.

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Abstract PO-082: Antigen presentation and inflammatory effects on immune surveillance: Window of opportunity metformin monotherapy trial for squamous cell carcinoma of the head and neck (HNSCC)

Abstract Introduction: The tumor microenvironment frequently displays dysregulated cellular metabolism, which contributes to aggressive behavior of the tumor. Though the mechanism of effect is unclear, clinical data suggest an association between metformin and improved outcomes in head and neck squamous cell carcinoma (HNSCC). The aim of this study is to investigate post-metformin treatment effects on the tumor microenvironment (TME) of HNSCC by using spatial RNA sequencing data from a metformin monotherapy window-of-opportunity clinical trial. Methods: This was a single-center prospective clinical trial of metformin in patients with HNSCC and a plan for definitive surgical resection. Primary lesions were biopsied prior to treatment and compared to matched post-treatment surgical specimens. Following biopsy-proven HNSCC diagnosis, metformin was initiated at 500 mg/day and increased to 1,000 mg twice daily by day 6. Spatial RNA sequencing of 18,000+ genes in CD45, CD163, and PanCK segments was conducted using Nanostring’s GeoMx digital spatial profiling (DSP). Sequencing data was analyzed by using unbiased gene set enrichment analysis (GSEA) and reported as a rank in gene list from 18,000+ total genes for post- vs pre-treatment analyses. Results: In all HPV positive, post-treatment samples in all three segments, GSEA demonstrated enrichment of antigen presenting cell types including NK cells, monocytes, and dendritic cells (q< 0.001). Inflammatory and metabolism signatures (IFN-y, IFN-a, oxidative phosphorylation) were enriched after metformin monotherapy in HPV+ samples within the PanCK positive segment (q< 0.001). Epithelial mesenchymal transition (EMT) was noted to be positively enriched while plasma cell signatures were negatively enriched within in HPV- post-treatment samples in the CD163 segment (q< 0.001). Within the CD45 positive segment, enriched expression of mRNAs for ribosomal-protein subsets were noted in T-cell gene sets and not in B-cell gene sets; in the CD45 segment, cytoplasmic ribosomal proteins is the second-most enriched gene set from C2 canonical pathways gene sets. Conclusion: Antigen presentation, inflammation, and ribosomal protein encoding genes were enriched with metformin monotherapy in the window of opportunity setting for HNSCC. Ribosomal proteins may also play a role in antigen presentation and immune surveillance in the post-treatment setting. Further research is required to describe the TME effects of metformin monotherapy and its effects on treatment response. Citation Format: Derek S. Mann, Sruti Tekumalla, Amiti Jain, Jacob Riordan, Alban Linnenbach, Diana Menezes, Ubaldo Martinez-Outschoorn, Joseph M. Curry. Antigen presentation and inflammatory effects on immune surveillance: Window of opportunity metformin monotherapy trial for squamous cell carcinoma of the head and neck (HNSCC) [abstract]. In: Proceedings of the AACR-AHNS Head and Neck Cancer Conference: Innovating through Basic, Clinical, and Translational Research; 2023 Jul 7-8; Montreal, QC, Canada. Philadelphia (PA): AACR; Clin Cancer Res 2023;29(18_Suppl):Abstract nr PO-082.

The emerging family of RORγt+ antigen-presenting cells.

Antigen-presenting cells (APCs) are master regulators of the immune response by directly interacting with T cells to orchestrate distinct functional outcomes. Several types of professional APC exist, including conventional dendritic cells, B cells and macrophages, and numerous other cell types have non-classical roles in antigen presentation, such as thymic epithelial cells, endothelial cells and granulocytes. Accumulating evidence indicates the presence of a new family of APCs marked by the lineage-specifying transcription factor retinoic acid receptor-related orphan receptor-γt (RORγt) and demonstrates that these APCs have key roles in shaping immunity, inflammation and tolerance, particularly in the context of host-microorganism interactions. These RORγt+ APCs include subsets of group 3 innate lymphoid cells, extrathymic autoimmune regulator-expressing cells and, potentially, other emerging populations. Here, we summarize the major findings that led to the discovery of these RORγt+ APCs and their associated functions. We discuss discordance in recent reports and identify gaps in our knowledge in this burgeoning field, which has tremendous potential to advance our understanding of fundamental immune concepts.

Comparative analysis of antigen-presenting cells in gingival tissues in healthy and periodontitis patients

AimsMicrobial flora of dental plaque trigger innate and adaptive immune responses. The function of antigen-presenting cells (APCs) is to bridge the innate and adaptive immune systems. The human immune system...

Lipid-Polymer Hybrid Nanoparticles Utilize B Cells and Dendritic Cells to Elicit Distinct Antigen-Specific CD4+ and CD8+ T Cell Responses.

Antigen-presenting cells (APCs) are widely studied for treating immune-mediated diseases, and dendritic cells (DCs) are potent APCs that uptake and present antigens (Ags). However, DCs face several challenges that hinder their clinical translation due to their inability to control Ag dosing and low abundance in peripheral blood. B cells are a potential alternative to DCs, but their poor nonspecific Ag uptake capabilities compromise controllable priming of T cells. Here, we developed phospholipid-conjugated Ags (L-Ags) and lipid-polymer hybrid nanoparticles (L/P-Ag NPs) as delivery platforms to expand the range of accessible APCs for use in T cell priming. These delivery platforms were evaluated using DCs, CD40-activated B cells, and resting B cells to understand the impacts of various Ag delivery mechanisms for generation of Ag-specific T cell responses. L-Ag delivery (termed depoting) of MHC class I- and II-restricted Ags successfully loaded all APC types in a tunable manner and primed both Ag-specific CD8+ and CD4+ T cells, respectively. Incorporating L-Ags and polymer-conjugated Ags (P-Ag) into NPs can direct Ags to different uptake pathways to engineer the dynamics of presentation and shape T cell responses. DCs were capable of processing and presenting Ag delivered from both L- and P-Ag NPs, yet B cells could only utilize Ag delivered from L-Ag NPs, which led to differential cytokine secretion profiles in coculture studies. Altogether, we show that L-Ags and P-Ags can be rationally paired within a single NP to leverage distinct delivery mechanisms to access multiple Ag processing pathways in two APC types, offering a modular delivery platform for engineering Ag-specific immunotherapies.

Expression of cytokines and co-stimulatory molecules in the Toxoplasma gondii-infected dendritic cells of C57BL/6 and BALB/c mice.

Toxoplasma gondii is an intracellular protozoan parasite which can infect most warm-blooded animals and humans. Among the different mouse models, C57BL/6 mice are more susceptible to T. gondii infection compared to BALB/c mice, and this increased susceptibility has been attributed to various factors, including T-cell responses. Dendritic cells (DCs) are the most prominent type of antigen-presenting cells and regulate the host immune response, including the response of T-cells. However, differences in the DC responses of these mouse strains to T. gondii infection have yet to be characterized. In this study, we cultured bone marrow-derived DCs (BMDCs) from BALB/c and C57BL/6 mice. These cells were infected with T. gondii. The activation of the BMDCs was assessed based on the expression of cell surface markers and cytokines. In the BMDCs of both mouse strains, we detected significant increases in the expression of cell surface T-cell co-stimulatory molecules (major histocompatibility complex (MHC) II, CD40, CD80, and CD86) and cytokines (tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-12p40, IL-1β, and IL-10) from 3 h post-T. gondii infection. The expression of MHC II, CD40, CD80, CD86, IFN-γ, IL-12p40, and IL-1β was significantly higher in the T. gondii-infected BMDCs obtained from the C57BL/6 mice than in those from the BALB/c mice. These findings indicate that differences in the activation status of the BMDCs in the BALB/c and C57BL/6 mice may account for their differential susceptibility to T. gondii.

Factor VIII trafficking to CD4+ T cells shapes its immunogenicity and requires several types of antigen-presenting cells

AbstractDespite >80 years of clinical experience with coagulation factor VIII (FVIII) inhibitors, surprisingly little is known about the in vivo mechanism of this most serious complication of replacement therapy for hemophilia A. These neutralizing antidrug alloantibodies arise in ∼30% of patients. Inhibitor formation is T-cell dependent, but events leading up to helper T-cell activation have been elusive because of, in part, the complex anatomy and cellular makeup of the spleen. Here, we show that FVIII antigen presentation to CD4+ T cells critically depends on a select set of several anatomically distinct antigen-presenting cells, whereby marginal zone B cells and marginal zone and marginal metallophilic macrophages but not red pulp macrophages (RPMFs) participate in shuttling FVIII to the white pulp in which conventional dendritic cells (DCs) prime helper T cells, which then differentiate into follicular helper T (Tfh) cells. Toll-like receptor 9 stimulation accelerated Tfh cell responses and germinal center and inhibitor formation, whereas systemic administration of FVIII alone in hemophilia A mice increased frequencies of monocyte-derived and plasmacytoid DCs. Moreover, FVIII enhanced T-cell proliferation to another protein antigen (ovalbumin), and inflammatory signaling–deficient mice were less likely to develop inhibitors, indicating that FVIII may have intrinsic immunostimulatory properties. Ovalbumin, which, unlike FVIII, is absorbed into the RPMF compartment, fails to elicit T-cell proliferative and antibody responses when administered at the same dose as FVIII. Altogether, we propose that an antigen trafficking pattern that results in efficient in vivo delivery to DCs and inflammatory signaling, shape the immunogenicity of FVIII.

Spatiotemporal regulation of peripheral T cell tolerance

The incomplete removal of T cells that are reactive against self-proteins during their differentiation in the thymus requires mechanisms of tolerance that prevent their effector function within the periphery. A further challenge is imposed by the need to establish tolerance to the holobiont self, which comprises a highly complex community of commensal microorganisms. Here, we review recent advances in the investigation of peripheral T cell tolerance, focusing on new insights into mechanisms of tolerance to the gut microbiota, including tolerogenic antigen-presenting cell types and immunomodulatory lymphocytes, and their layered ontogeny that underlies developmental windows for establishing intestinal tolerance. While emphasizing the intestine as a model tissue for studying peripheral T cell tolerance, we highlight overlapping and distinct pathways that underlie tolerance to self-antigens versus commensal antigens within a broader framework for immune tolerance.

The role of interleukin-12-PRMT5 axis in generating suppressive Th1-like induced regulatory T cells

Abstract After activation, naïve CD4 T cells can differentiate into T helper cell subsets (Th1, Th2, Th17, and Follicular helper T cells) or into regulatory T cells (Tregs), depending on the type of antigen-presenting cells (APC) and cytokine milieu encountered during differentiation. Recent studies suggest that CD4+Foxp3+ Tregs can produce the pro-inflammatory cytokine IFNg when stimulated in a Th1 cytokine environment, such as in the presence of IL-12, and stimulation under these conditions makes iTregs sensors for inflammatory cytokines. The stability and suppressive functions of the iTregs depend on multiple factors. The goal of this study is to explore an epigenetic enzyme protein arginine methyltransferase 5 (PRMT5) and to understand the significance of this protein in the development of Th1-like iTregs. PRMT5 can either represses or activate transcription of target genes via symmetric di-methylation of arginine residues on histones. However, the role of PRMT5 in the differentiation of Th1-like iTregs has not been thoroughly investigated. We demonstrate that differentiating iTregs in a Th1 cytokine environment generated a specific population of Th1-like iTregs with increased suppressive function. In Th1-like iTregs, we observed symmetric arginine di-methylation on histone (H3R2me2s) mediated by PRMT5, while this epigenetic marker is absent in iTregs. We also demonstrate that si-RNA mediated knockdown of PRMT5 reduced the suppressive capacity of Th1-like iTregs. Therefore, we hypothesize that the IL12-PRMT5 axis is crucial for developing suppressive Th1-like iTregs. Goals of further research are to generate stable immunosuppressive iTregs for therapeutic use.

Dissecting the roles of CD91 in heat shock protein-mediated cancer immunosurveillance

Abstract Our lab has shown that cancer immunosurveillance is dependent on CD91, a receptor for heat shock proteins (HSPs), which is expressed on antigen-presenting cells (APCs). HSP-chaperoned tumor antigens are cross-presented following endocytosis by CD91. Binding of HSPs to CD91 also initiates an intracellular signaling pathway that is poorly understood. Two tyrosine residues on the intracellular domain (β-chain) of CD91 become phosphorylated following HSP binding, leading to downstream activation of NF-kB and STAT1. We found that the immunogenic HSPs differentially utilize these two phosphorylation sites on CD91 for downstream signaling resulting in unique cytokine profiles and co-stimulation capacity. We investigate here the CD91-interacting adaptor proteins and kinases by crosslinking and co-immunoprecipitation of CD91 and its signaling complex following stimulation with each immunogenic HSP (gp96, calreticulin or hsp70). Mass spectrometry studies with gp96 identified the adaptor protein Shc and two other receptor tyrosine kinase associated with CD91. Inhibition of these kinases leads to a significant decrease in gp96-mediated cytokine production. Further work is being done to elucidate the remainder of this signaling network for each HSP and examine any differences between APC types. This project will aid in better understanding of how CD91-mediated signaling differentially activates effector cytokine profiles in APCs. This knowledge can be used in the development of new therapeutic approaches to enhance immunosurveillance of cancers and to better eradicate established disease.

DM functions differently in thymic antigen presentation cell subsets in development of autoreactive CD4+ T cells

Abstract Autoreactive CD4+ T cells broadly exist in healthy individuals and potentially cause autoimmune diseases; however, why they can escape from thymic negative selection is still controversial. We observed that the activity of DM, a peptide epitope editor in MHC class II antigen presentation pathway, is differentially regulated in different thymic antigen presenting cells (APC). It is high in cTEC that involved in cortical positive selection, but low in mTEC, B cell, pDC and cDC that mediate negative selection in medulla, while it remains high in all types of peripheral APC. The molecular mechanism of differential regulation is still unknown. It is not directly inhibited by DO, a negative regulator of DM that directly competes DM catalytic site with peptide-MHC class II complex, since DM editing activity remains low in those thymic medulla APC in DO−/− mice. We further confirmed that presentation of autoantigen epitope MOG35–55 for thymic positive selection and in vitro activation of autoreactive CD4+ T cells in EAE, a mouse model of human multiple sclerosis disease, is DM dependent. This is also true for presentation of insulin epitope B9–23 to activate autoreactive CD4+ T cells restricted to type 1 diabetes associated HLA-DQ8. Our findings highlighted a fundamental mechanism that immune system differentially regulates DM activity in thymus to balance the efficiency of negative selection to minimize autoimmunity and the maximum of T cell repertoire to defend infection; however, the DM-dependency property of certain autoantigen epitopes accidently caused the failure deletion of autoreactive CD4+ T cells.

Cell-specific MHC class I deletion on CD11c+ APCs abrogates CD8 T Cell infiltration into the brain

Abstract Cerebral malaria (CM) is a severe complication of P. falciparum infection and a leading cause of death, globally. Plasmodium berghei ANKA (PbA) infection of C57BL/6 mice serves as a murine model of CM called experimental cerebral malaria (ECM) due to the neurological and neuropathological features that simulate the infection of human CM. A putative mechanism of disease in human CM requires CD8 T cell to infiltration into the brain and blood-brain barrier disruption. The specific antigen-presenting cell type(s) that prime this CNS infiltrating CD8 T cell response capable of inducing lethal blood-brain barrier disruption has not been defined. To answer this, single class I expressing K bloxP transgenic mice were generated. Crossing these mice to class I deficient CD11c-cre or LysM-cre mice created the LysM-cre K bcKO and CD11c-cre K bcKO mice, respectively. PbA infected K bloxP and LysM-cre K bcKO were susceptible to ECM. In contrast, CD11c-cre K bcKO mice survived acute PbA infection and avoided neurological manifestations. We therefore employed spectral flow cytometry to analyze splenocytes and brain infiltrating immune cells during acute PbA infection in these genotypes. We observed a reduction in activated CD8 T cells in the spleens of PbA infected CD11c-cre K bcKO mice versus the K bloxP mice and the LysM-cre K bcKO. This reduced peripheral CD8 T cell activation in PbA infected CD11c-cre Kb cKO mice also corresponded with reduced brain infiltration of CD8 T cells. We conclude a CD11c+ APC is therefore required for priming and potentially recruitment of CD8 T cells to the brain during lethal ECM pathology. 5R01NS103212-06

The construction of a novel ferroptosis-related lncRNA model to predict prognosis in colorectal cancer patients.

Colorectal cancer (CRC) is the most common gastrointestinal tumor with poor prognosis. Ferroptosis is a pivotal form of programmed iron-dependent cell death different from autophagy and apoptosis, and long noncoding RNA (lncRNA) can influence the prognosis of CRC via regulating ferroptosis. To explore the role and prognostic value of the constructed ferroptosis-related lncRNA model in CRC, a prognostic model was constructed and validated by screening ferroptosis-related lncRNAs associated with prognosis based on the transcriptome data and survival data of CRC patients in The Cancer Genome Atlas database. Regarding the established prognostic models, differences in signaling pathways and immune infiltration, as well as differences in immune function, immune checkpoints, and N6-methyladenosine-related genes were also analyzed. A total of 6 prognostic ferroptosis-related lncRNAs were obtained, including AP003555.1, AC010973.2, LINC01857, AP001469.3, ITGB1-DT and AC129492.1. Univariate independent prognostic analysis, multivariate independent prognostic analysis and receiver operating characteristic curves showed that ferroptosis-related lncRNAs could be recognized as independent prognostic factors. The Kaplan-Meier survival curves and the risk curves showed that the survival time of the high-risk group was shorter. Gene set enrichment analysis enrichment analysis showed that ATP-binding cassette transporters, taste transduction and VEGF signaling pathway were more active in high-risk groups that than in low-risk groups. However, the citrate cycle tricarboxylic acid cycle, fatty acid metabolism and peroxisome were significantly more active in the low-risk group than in the high-risk group. In addition, there were also differences in immune infiltration in the high-low-risk groups based on different methods, including antigen-presenting cell co-stimulation, chemokine receptor, parainflammation, and Type II IFN Response. Further analysis of Immune checkpoints showed that most of the Immune checkpoints such as TNFRSF18, LGALS9 and CTLA4 in the high-risk group were significantly higher than those in the low-risk group, and the expressions of N6-methyladenosine related genes METTL3, YTHDH2 and YTHDC1 were also significantly different in the high-risk group. Ferroptosis-related lncRNAs are closely related to the survival of colorectal cancer patients, which can be used as new biomarkers and potential therapeutic targets for the prognosis of colorectal cancer.

Targeting STING to promote antitumor immunity.

Pharmacology-based methods that promote antitumor immunity have the potential to be highly efficacious while avoiding the systemic cytotoxicity associated with traditional chemotherapies. Activation of type I interferon (IFN) signaling in antigen-presenting cell types [e.g., macrophages and dendritic cells (DCs)] is critical, if not essential, for inducing a tumor-specific adaptive immune response, including the activation of cytolytic CD8 T cells. In the context of promoting antitumor immunity, the cyclic GMP-AMP synthase/stimulator of IFN genes (cGAS/STING) pathway has emerged as a principal regulator of essential type I IFN signaling. As such, STING represents a highly attractive target for developing a first-in-class immunotherapy, albeit one with a potential for significant cell type- and downstream pathway-dependent on-target toxicities, as well as conceivable pharmacogenomic liabilities.

Biomimetic dendritic polymeric microspheres induce enhanced T cell activation and expansion for adoptive tumor immunotherapy

A variety of bioactive materials are currently developed to expand T cells ex vivo for adoptive T cell immunotherapy, also known as called artificial antigen-presenting cells (aAPCs). However, almost all the reported designs exhibit relatively smooth surface modified with T cell activating biomolecules, and therefore cannot well mimic the dendritic morphological characteristics of dendritic cells (DCs), the most important type of natural antigen-presenting cells (APCs) with high specific surface areas. Here, we propose a hydrophilic monomer-mediated surface morphology control strategy to synthesize biocompatible dendritic poly(N-isopropylacrylamide) (PNIPAM) microspheres for constructing aAPCs with surface morphology mimicking natural APCs (e.g., DCs). Interestingly, when maintaining the same ligands density, dendritic polymeric microspheres-based aAPCs (DPM beads) can more efficiently expand CD8+ T cells than that with smooth surfaces. Moreover, adoptive transfer of antigen-specific CD8+ T cells expanded by the DPM beads show significant antitumor effect of B16-OVA tumor bearing mice. Therefore, we provide a new concept for constructing biomimetic aAPCs with enhanced T cell expansion ability.

Cell-penetrating albumin enhances the sublingual delivery of antigens through macropinocytosis

Innovations in oral immunotherapy have greatly advanced the therapeutic control of allergies. However, these therapeutic effects suffer from the fact that the amount of antigen delivered to antigen-presenting cells is limited given the formulations that are currently available. We recently designed a cell-penetrating albumin and found that this modified albumin enters cells via the induction of macropinocytosis. Herein, we report on a novel system for delivering antigens based on cell-penetrating albumin-inducible macropinocytosis that allows larger amounts of antigens to be delivered to antigen-presenting cells. A treatment with cell-penetrating albumin significantly increased the permeability of ovalbumin (45 kDa) or dextran (2000 kDa) on monolayers derived from human oral squamous carcinoma cells. Flow cytometric analyses showed that the cell-penetrating albumin treatment resulted in a significant elevation in the amount of dextran that was delivered to two types of antigen-presenting cells. Finally, mice that had been sensitized by Japanese cedar pollen extract (JCPE) and cell-penetrating albumin showed a decline in the frequency of nose-rubbing against a subsequent intranasal administration of JCPE. These findings suggest that the sublingual administration of cell-penetrating albumin efficiently delivers antigens to antigen-presenting cells via the induction of macropinocytosis, resulting in an enhancement in the therapeutic effect of sublingual immunotherapy.

Mass spectrometry and immunopeptidomics – teaching us new lessons in antigen processing and presentation

Immunopeptidomics is the study of the repertoire of peptide ligands selected for antigen presentation by MHC class 1 molecules. In recent years, this has been revolutionised by the use of in depth qualitative and quantitative mass spectrometry techniques. In particular, fundamental and novel insights have been made that shed light on the dynamic range of antigen presentation, the role of HLA polymorphism, antigen presenting cell type and mode of antigen processing on the resultant immunopeptidome, as well as diversity introduced by degenerate proteolysis and extensive post-translational modifications. I will highlight recent advances in analytical workflows and how these have provided new insights into antigen processing and presentation by selecting recent published and unpublished examples from our laboratory 1-7 .