Surface Of Antigen-presenting Cells Research Articles

Immunomodulatory Roles of IL-15 in Immune Cells and its Potential for Cancer Immunotherapy.

Interleukin-15 (IL-15) was identified in 1994 as a T-cell growth factor with the capability to mimic the functions of IL-2. IL-15 engages with the IL-15Rα subunit expressed on the surface of antigen-presenting cells (APCs) and, through a trans-presentation mechanism, activates the IL-2/IL-15Rβγ complex receptor on the surface of natural killer (NK) cells and CD8+ T cells. This interaction initiates a cascade of downstream signaling pathways, playing a pivotal role in the activation, proliferation, and anti-apoptotic processes in NK cells, CD8+ T cells, and B cells. It provides a substantial theoretical foundation and potential therapeutic targets for tumor immunotherapy. Whether through active or passive immunotherapeutic strategies, IL-15 has emerged as a critical molecule for stimulating anti-tumor cell proliferation.

Bayesian metamodeling of early T-cell antigen receptor signaling accounts for its nanoscale activation patterns.

T cells respond swiftly, specifically, sensitively, and robustly to cognate antigens presented on the surface of antigen presenting cells. Existing microscopic models capture various aspects of early T-cell antigen receptor (TCR) signaling at the molecular level. However, none of these models account for the totality of the data, impeding our understanding of early T-cell activation. Here, we study early TCR signaling using Bayesian metamodeling, an approach for systematically integrating multiple partial models into a metamodel of a complex system. We inform the partial models using multiple published super-resolution microscopy datasets. Collectively, these datasets describe the spatiotemporal organization, activity, interactions, and dynamics of TCR, CD45 and Lck signaling molecules in the early-forming immune synapse, and the concurrent membrane alterations. The resulting metamodel accounts for a distinct nanoscale dynamic pattern that could not be accounted for by any of the partial models on their own: a ring of phosphorylated TCR molecules, enriched at the periphery of early T cell contacts and confined by a proximal ring of CD45 molecules. The metamodel suggests this pattern results from limited activity range for the Lck molecules, acting as signaling messengers between kinetically-segregated TCR and CD45 molecules. We assessed the potential effect of Lck activity range on TCR phosphorylation and robust T cell activation for various pMHC:TCR association strengths, in the specific setting of an initial contact. We also inspected the impact of localized Lck inhibition via Csk recruitment to pTCRs, and that of splicing isoforms of CD45 on kinetic segregation. Due to the inherent scalability and adaptability of integrating independent partial models via Bayesian metamodeling, this approach can elucidate additional aspects of cell signaling and decision making.

Selective HLA Class II Allele-Restricted Activation of Atabecestat Metabolite-Specific Human T-Cells.

Elevations in hepatic enzymes were detected in several trial patients exposed to the Alzheimer's drug atabecestat, which resulted in termination of the drug development program. Characterization of hepatic T-lymphocyte infiltrates and diaminothiazine (DIAT) metabolite-responsive, human leukocyte antigen (HLA)-DR-restricted, CD4+ T-lymphocytes in the blood of patients confirmed an immune pathogenesis. Patients with immune-mediated liver injury expressed a restricted panel of HLA-DRB1 alleles including HLA-DRB1*12:01, HLA-DRB1*13:02, and HLA-DRB1*15:01. Thus, the objectives of this study were to (i) generate DIAT-responsive T-cell clones from HLA-genotyped drug-naive donors, (ii) characterize pathways of DIAT-specific T-cell activation, and (iii) assess HLA allele restriction of the DIAT-specific T-cell response. Sixteen drug-naive donors expressing the HLA-DR molecules outlined above were recruited, and T-cell clones were generated. Cellular phenotype, function, and HLA-allele restriction were assessed using culture assays. Peptides displayed by HLA class II molecules in the presence and absence of atabecestat were analyzed by mass spectrometry. Several DIAT-responsive CD4+ clones, displaying no reactivity toward the parent drug, were successfully generated from donors expressing HLA-DRB1*12:01, HLA-DRB1*13:02, and HLA-DRB1*15:01 but not from other donors expressing other HLA-DRB1 alleles. T-cell clones were activated following direct binding of DIAT to HLA-DR proteins expressed on the surface of antigen presenting cells. DIAT binding did not alter the HLA-DRB1 peptide binding repertoire, indicative of a binding interaction with the HLA-associated peptide rather than with the HLA protein itself. DIAT-specific T-cell responses displayed HLA-DRB1*12:01, HLA-DRB1*13:02, and HLA-DRB1*15:01 restriction. These data demonstrate that DIAT displays a degree of selectivity toward HLA protein and associated peptides, with expression of certain alleles increasing and that of others decreasing, the likelihood that a drug-specific T-cell response develops.

DiscovEpi: automated whole proteome MHC-I-epitope prediction and visualization

BackgroundAntigen presentation is a central step in initiating and shaping the adaptive immune response. To activate CD8+ T cells, pathogen-derived peptides are presented on the cell surface of antigen-presenting cells bound to major histocompatibility complex (MHC) class I molecules. CD8+ T cells that recognize these complexes with their T cell receptor are activated and ideally eliminate infected cells. Prediction of putative peptides binding to MHC class I (MHC-I) is crucial for understanding pathogen recognition in specific immune responses and for supporting drug and vaccine design. There are reliable databases for epitope prediction algorithms available however they primarily focus on the prediction of epitopes in single immunogenic proteins.ResultsWe have developed the tool DiscovEpi to establish an interface between whole proteomes and epitope prediction. The tool allows the automated identification of all potential MHC-I-binding peptides within a proteome and calculates the epitope density and average binding score for every protein, a protein-centric approach. DiscovEpi provides a convenient interface between automated multiple sequence extraction by organism and cell compartment from the database UniProt for subsequent epitope prediction via NetMHCpan. Furthermore, it allows ranking of proteins by their predicted immunogenicity on the one hand and comparison of different proteomes on the other. By applying the tool, we predict a higher immunogenic potential of membrane-associated proteins of SARS-CoV-2 compared to those of influenza A based on the presented metrics epitope density and binding score. This could be confirmed visually by comparing the epitope maps of the influenza A strain and SARS-CoV-2.ConclusionAutomated prediction of whole proteomes and the subsequent visualization of the location of putative epitopes on sequence-level facilitate the search for putative immunogenic proteins or protein regions and support the study of adaptive immune responses and vaccine design.

Double synergic chitosan-coated poly (lactic-co-glycolic) acid nanospheres loaded with nucleic acids as an intranasally administered vaccine delivery system to control the infection of foot-and-mouth disease virus

The spread of foot-and-mouth disease virus (FMDV) through aerosol droplets among cloven-hoofed ungulates in close contact is a major obstacle for successful animal husbandry. Therefore, the development of suitable mucosal vaccines, especially nasal vaccines, to block the virus at the initial site of infection is crucial. Here, we constructed eukaryotic expression plasmids containing the T and B-cell epitopes (pTB) of FMDV in tandem with the molecular mucosal adjuvant Fms-like tyrosine kinase receptor 3 ligand (Flt3 ligand, FL) (pTB-FL). Then, the constructed plasmid was electrostatically attached to mannose-modified chitosan-coated poly(lactic-co-glycolic) acid (PLGA) nanospheres (MCS-PLGA-NPs) to obtain an active nasal vaccine targeting the mannose-receptor on the surface of antigen-presenting cells (APCs). The MCS-PLGA-NPs loaded with pTB-FL not only induced a local mucosal immune response, but also induced a systemic immune response in mice. More importantly, the nasal vaccine afforded an 80% protection rate against a highly virulent FMDV strain (AF72) when it was subcutaneously injected into the soles of the feet of guinea pigs. The nasal vaccine prepared in this study can effectively induce a cross-protective immune response against the challenge with FMDV of same serotype in animals and is promising as a potential FMDV vaccine.

Investigating MAIT cell phenotype using MR1 and TCR Dextramer™ reagents

Abstract Objective Here, we demonstrate a workflow, which enables the study of mucosal-associated invariant T (MAIT) cells using MR1 reagents. The workflow covers initial detection of MAIT cells with TCR sequencing as well as cloning, production, and validation of selected MAIT TCR molecules. Methods Human PBMC samples were stained with relevant antibodies and MR1/5-OP-RU dCODE Dextramer™ reagents. Following staining, sorting, and partitioning on a BD RhapsodyTM Single-Cell Analysis System, the cells underwent sequencing for characterization of gene and surface marker expression as well as paired alpha-beta TCR sequences. Selected TCR sequences were produced as TCR molecules and subsequently used to detect MR1/5-OP-RU on the surface of antigen-presenting cells. Results The majority (70%) of the MAIT cells express typical TCRs containing TRAV1-2 and TRAJ33 gene segments. The remaining MR1/5-OP-RU-reactive MAIT cells express highly diverse, non-classical MAIT TCR sequences. The three most frequent TCR clonotypes were produced and their specificity validated using in vitro assays and staining of MR1/5-OP-RU-presenting cells. Summary Our workflow allows identification of MAIT cells and elucidation of their TCR sequences. The high sensitivity of MR1 dCODE Dextramer reagents enables detection of both weak interactions and rare cell types. Subsequent production of MAIT TCR molecules allows deeper characterization of individual MAIT cell specificity and its role in health and disease.

Hepatic mRNA expression of innate and adaptive immune genes in beef steers with divergent residual body weight gain

Immune function plays a pivotal role in dictating the overall health and productivity of cattle. In a proficient immune system, the liver assumes an integral function in detoxification and metabolic processes and contributes substantially to overall production and immunity. In this study, we evaluated the hepatic mRNA expression of genes involved in innate and adaptive immunity in crossbred beef steers with positive or negative residual body weight gain (RADG). Positive-RADG beef steers (n = 8; RADG = 0.73 kg/d) and negative-RADG beef steers (n = 8; RADG = -0.69 kg/d) were identified from a group of 108 growing crossbred beef steers (average BW = 556 ± 38 kg) after a 56-d performance testing period. At the end of the 56-d period, liver tissue samples were collected from the beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes involved in innate and adaptive immunity were analyzed using pathway-focused PCR-based arrays. The mRNA expression of genes with false discovery rate-adjusted P-values (FDR) ≤ 0.05 and absolute fold change (FC) ≥ 1.2 were determined to be differentially expressed. Out of the 84 genes analyzed, four genes (IL-2, MYD88, CD-80, NFkB-1) were differentially expressed and were all upregulated in positive compared with negative-RADG beef steers. IL-2 is a cytokine that plays a critical role in the immune response by activating and proliferating T-cells, which are important for fighting infections. MYD88 is an adaptor protein that is essential for signaling by toll-like receptors, which are involved in pathogen recognition. CD80 is a protein that is expressed on the surface of antigen-presenting cells and plays a critical role in the initiation of an immune response. The activation of NF-κB leads to the production of cytokines and chemokines that help to recruit immune cells to the site of infection. The upregulation of the aforementioned genes in positive-RADG beef steers suggests that they had a better ability than negative-RADG beef steers to quickly recognize pathogens and initiate appropriate responses to effectively fight off infections without causing inflammatory reactions, potentially contributing to their better feed efficiency.

Clathrin controls bidirectional communication between T cells and antigen presenting cells.

In circulation, T cells are spherical with selectin enriched dynamic microvilli protruding from the surface. Following extravasation, these microvilli serve another role, continuously surveying their environment for antigen in the form of peptide-MHC (pMHC) expressed on the surface of antigen presenting cells (APCs). Upon recognition of their cognate pMHC, the microvilli are initially stabilized and then flatten into F-actin dependent microclusters as the T cell spreads over the APC. Within 1-5 min, clathrin is recruited by the ESCRT-0 component Hrs to mediate release of T cell receptor (TCR) loaded vesicles directly from the plasma membrane by clathrin and ESCRT-mediated ectocytosis (CEME). After 5-10 min, Hrs is displaced by the endocytic clathrin adaptor epsin-1 to induce clathrin-mediated trans-endocytosis (CMTE) of TCR-pMHC conjugates. Here we discuss some of the functional properties of the clathrin machinery which enables it to control these topologically opposite modes of membrane transfer at the immunological synapse, and how this might be regulated during T cell activation.

Modern ideas about the etiopathogenesis of rheumatoid arthritis

This review reflects modern ideas about the etiology and pathogenesis of Rheumatoid arthritis (RA). The disease is believed to be caused by various external or internal stress factors in individuals with a genetic predisposition. Under modern concepts, RA is an autoimmune disease, and the basis of its pathogenesis is the defects of the regulatory mechanisms providing the activation of the immune system against various stimuli. The onset of RA is in the peripheral lymphoid organs. Dendritic cells activate T-lymphocytes, activating B-lymphocytes through cytokines and costimulatory molecules, and cause the synthesis of autoantibodies, the accumulation of immune complexes in the joints, and the development of rheumatoid synovitis. B-lymphocytes secrete rheumatoid factor (RF), antibodies to cyclic citrulline peptide (ACCP), and proinflammatory cytokines and also activate T-lymphocytes by indicating signaling molecules. During T-lymphocyte activation, CD4+ Th-cells interact with HLA, MHC-II molecules, and costimulatory molecules located on the surface of antigen-presenting cells. This interaction activates a signaling pathway leading to the maturation of CD4+ cells, resulting in the activation of pro-inflammatory CD8+ T-lymphocytes. CD4+ Th cells also play an important role in RA regeneration through the secretion of cytokines and chemokines, the important immunomodulators of cellular immunity.

PSIII-10 Hepatic Mrna Expression of Genes Related to Innate and Adaptive Immune Genes in Beef Steers with Divergent Residual Body Weight Gain

Abstract Immune function plays an important role in overall animal health and productivity. In this study, we evaluated the hepatic mRNA expression of genes involved in innate and adaptive immunity in crossbred beef steers with positive or negative residual body weight gain (RADG). Positive-RADG beef steers (n = 8; RADG = 0.34 kg/d) and negative-RADG beef steers (n = 8; RADG = -0.27 kg/d) were selected from a group of 108 growing crossbred beef steers (average BW = 556 ± 38 kg) after a 42-d performance testing period. At the end of the 42-d period, liver biopsies were collected from the beef steers for RNA extraction and cDNA synthesis. The mRNA expression of 84 genes involved in innate and adaptive immunity were analyzed using pathway-focused PCR-based arrays. The mRNA expression of genes with false discovery rate-adjusted P-values (FDR) ≤ 0.05 were considered to be differentially expressed. Out of the 84 genes analyzed, four genes (IL-2, MYD88, CD-80, NFkB-1) were differentially expressed and were all upregulated in positive-RADG, compared with negative-RADG beef steers. IL-2 is a cytokine that plays a critical role in the immune response by activating and proliferating T-cells, which are important for fighting infections. MYD88 is an adaptor protein that is essential for signaling by toll-like receptors, which are involved in pathogen recognition. CD80 is a protein that is expressed on the surface of antigen-presenting cells and plays a critical role in the initiation of an immune response. The activation of NF-κB leads to the production of cytokines and chemokines that help to recruit immune cells to the site of infection. The upregulation of the aforementioned genes in positive-RADG beef steers suggests that they had a better ability than negative-RADG beef steers to quickly recognize pathogens and initiate appropriate responses to effectively fight off infections without causing inflammatory reactions. This is essential to optimize immune function and minimize the impact of immune activation on growth and production. As a result, more energy and nutrients are available to support improved growth rate and feed efficiency.

Cancer Cell Silicification and Surface Functionalization to Create Microbial Mimetic Cancer Vaccines.

As cancer progresses, tumor cells adapt to evade immune cells. To counter this, cancer cells can be silicified ex vivo, creating surface masks that can be decorated with microbial-associated molecules that are readily recognized by antigen-presenting cells (APCs). The transformation process renders the tumor cells nonviable and preserves the integrity of the cell and associated tumor antigens. The resulting personalized cancer vaccine, when returned to the patient, engages molecules on the surface of APC, activating signaling pathways that lead to immune cell activation, vaccine internalization, processing of tumor antigens, and major histocompatibility complex peptide presentation to T cells. The cancer-specific T cells then circulate throughout the body, killing tumor cells. This chapter presents detailed methods for the cryogenic precipitation of silica on cellular structures (cryo-silicification), creating vaccines that are potent immune activators. Further, silicified cells can be dehydrated for shelf storage, eliminating the need for costly cryogenic storage.

Targeting neoantigens to APC-surface molecules improves the immunogenicity and anti-tumor efficacy of a DNA cancer vaccine.

Tumor-specific mutations generate neoepitopes unique to the cancer that can be recognized by the immune system, making them appealing targets for therapeutic cancer vaccines. Since the vast majority of tumor mutations are patient-specific, it is crucial for cancer vaccine designs to be compatible with individualized treatment strategies. Plasmid DNA vaccines have substantiated the immunogenicity and tumor eradication capacity of cancer neoepitopes in preclinical models. Moreover, early clinical trials evaluating personalized neoepitope vaccines have indicated favorable safety profiles and demonstrated their ability to elicit specific immune responses toward the vaccine neoepitopes. By fusing in silico predicted neoepitopes to molecules with affinity for receptors on the surface of APCs, such as chemokine (C-C motif) ligand 19 (CCL19), we designed an APC-targeting cancer vaccine and evaluated their ability to induce T-cell responses and anti-tumor efficacy in the BALB/c syngeneic preclinical tumor model. In this study, we demonstrate how the addition of an antigen-presenting cell (APC) binding molecule to DNA-encoded cancer neoepitopes improves neoepitope-specific T-cell responses and the anti-tumor efficacy of plasmid DNA vaccines. Dose-response evaluation and longitudinal analysis of neoepitope-specific T-cell responses indicate that combining APC-binding molecules with the delivery of personalized tumor antigens holds the potential to improve the clinical efficacy of therapeutic DNA cancer vaccines. Our findings indicate the potential of the APC-targeting strategy to enhance personalized DNA cancer vaccines while acknowledging the need for further research to investigate its molecular mechanism of action and to translate the preclinical results into effective treatments for cancer patients.

Docking Analysis of Deltamethrin Pesticide with MHC I and MHC II Molecules to Establish Immunomodulation Effects

Background: Deltamethrin is a class II synthetic pyrethroid pesticide extensively used to control pests and vectors in the agriculture sector and health management programme. Due to excessive applications of this pesticide in the environment, it is harming many organisms other than the target organisms. Higher organisms like human beings are also affected by this pesticide because it instigates the impairment of the central nervous system and also distresses the immune system of vertebrates. Methods: In the current research study, MHC I and MHC II molecules of human origin have been targeted to evaluate the interaction with deltamethrin molecules by the AutoDock tool to establish the immunomodulatory effect. MHC I receptor molecule is presented on every nucleated cell, and MHC II receptors are located specifically on cell surfaces of antigen-presenting cells. These receptors play a role in cell-mediated and humoral immune responses. The binding affinity of deltamethrin with MHC receptors can affect the immune response, specifically the acquired immunity of an individual. Results: Findings of the current research study support that deltamethrin causes the suppression of the immune system by interaction with MHC I and MHC II molecules and may cause the organisms to be more prone towards antigen and disease development. Conclusion: The autoDock tool can be utilized to analyse other pesticides’ effects on the immune system and in the drug development process to minimize the toxic effects due to several types of pesticides.

The H2-A Class II molecule α/β-chain cis-mismatch severely affects cell surface expression, selection of conventional CD4+ T cells and protection against TB infection.

To dissect the role of the part of the H2 complex comprised of the MHC-II genes in the control of tuberculosis (TB) infection, we previously established a panel of recombinant congenic mouse strains bearing different segments of the H2 j haplotype on the B6 (H2 b) genetic background. Fine genetic mapping, gene sequencing and assessment of TB phenotypes resulted in identification of the H2-Ab gene as a major factor of TB control. We further narrowed the MHC-II H2 j interval by spotting a new recombination event, sequencing newly established DNA configuration and establishing a mouse strain B6.I-103 in which j/b recombination occurred within the coding sequence of the H2-Ab gene. Unexpectedly, a novel H2-Aα b/AβjE0 haplotype provided exclusively high susceptibility to TB challenge. Immunologic analysis revealed an altered CD4+ T-cell selection and maintenance in B6.I-103 mice, as well as seriously impaired expression of the H2-Aαb/Aβj molecule on the surface of antigen presenting cells. Unlike previously reported cases of Class II malfunctioning, the defective phenotype arose not from strong structural mutations, but from regular recombination events within the MHC-II recombination hot spot region. Our findings provide evidence that Class II α/β-chain cis-allelic mismatches created by regular genetic recombination may severely affect immune system functioning. This issue is discussed in the context of the MHC evolution.

Imaging the T-cell receptor: new approaches, new insights.

T cells recognize pathogenic antigens via the T-cell antigen receptor (TCR). This protein complex binds to antigen fragments on the surface of antigen-presenting cells. To understand how cellular activation can ensue rapidly from molecular recognition, the localization and distribution of the TCR on the surface of the resting T cell areof particular importance. Conflicting results regarding TCR distribution have emerged from recent studies using a range of imaging techniques, including total internal reflection and single-molecule localization microscopy modalities. Here, we review the differing results and the potential biases inherent in differing imaging approaches. In addition, we review studies showing the impact of differing imaging surfaces on T-cell activation.

Regulation of MHC class II and CD86 expression by March-I in immunity and disease.

The expression of MHC-II and CD86 on the surface of antigen-presenting cells (APCs) must be tightly regulated to foster antigen-specific CD4 T-cell activation and to prevent autoimmunity. Surface expression of these proteins is regulated by their dynamic ubiquitination by the E3 ubiquitin ligase March-I. March-I promotes turnover of peptide-MHC-II complexes on resting APCs and termination of March-I expression promotes MHC-II and CD86 surface stability. In this review, we will highlight recent studies examining March-I function in both normal and pathological conditions.

Immunological consequences of CD91 Single Nucleotide Polymorphisms in patients with sarcomas

Abstract Tumor immunosurveillance is critically dependent on several immune cell types and proteins including CD91. CD91 is expressed on the surface of antigen presenting cells (APCs) and binds a select few heat shock proteins (HSPs) released by dying tumor cells. These HSPs carry tumor antigens and initiate anti-tumor immune responses in de novotumors. We have previously shown among multiple sarcoma types, osteosarcomas are poorly infiltrated by T cells and poorly immune edited. This correlates with reduced expression of CD91 on the surface of intratumoral APCs. CD91 is a highly polymorphic gene within the human population. Over 3500 single nucleotide polymorphisms (SNPs) have been identified, despite the relatively high conservation of CD91 throughout evolution. We have identified 155 of these SNPs within our sarcoma patient population, 11 of which are exonic and non-synonymous. We analyzed the immunologic data we obtained from patients with non-synonymous SNPs to patients with normal CD91 protein sequences. In addition, we used the computational modeling programs SIFT and PolyPhen-2 to predict the effects of these mutations on CD91 protein folding. SNPs rs746886209 and rs758644665 were indicated by both SIFT and PolyPhen-2 to have deleterious effects on CD91 folding and patients with these mutations had below average immune infiltration. While these data are currently correlative, we have developed an in vitromodel to obtain proof of concept.

B cell responses to membrane-presented antigens require the function of the mechanosensitive calcium channel Piezo1

Abstract It has become increasingly evident that even though B cells respond to both soluble and membrane-presented antigens in vitro, the primary mode of antigen recognition in vivo appears to be of antigens on the surfaces of antigen-presenting cells. To determine how B cells sense that an antigen is membrane associated, we investigated the role of the Piezo1 mechanosensing cation channel in human B-cell activation. We discovered that human B cells flux calcium when simply poked by a glass probe or placed on a ridged glass surface, responses that were blocked by Piezo inhibitors. Piezo1 opens in response to changes in membrane tension and we showed that B cells placed on glass but not on soft planar lipid bilayers showed increased plasma membrane tension as measured by fluorescence lifetime imaging with a membrane tension reporter. B cell calcium responses to glass surfaces and to the Piezo1 antagonist Yoda1 were independent of BCR engagement. However, critically, B cell responses to membrane-presented antigens but not to soluble anti-Ig were inhibited both by Piezo1 inhibitors and by siRNA knockdown. In the absence of Piezo-1 function B cells engaging membrane-associated anti-Ig failed to flux calcium, spread on the membrane, form an immune synapse, increase plasma membrane tension, promote actin polymerization, increase expression of CD69 or proliferate. We conclude that Piezo1 plays a pivotal role in initiation of human B cell activation to membrane antigens. Postbaccalaureate Intramural Research Training Award - NIH OITE

Human adenovirus type 7 subunit vaccine induces dendritic cell maturation through the TLR4/NF-κB pathway is highly immunogenic.

Human adenovirus type 7 (HAdv-7) infection is the main cause of upper respiratory tract infection, bronchitis and pneumonia in children. At present, there are no anti- adenovirus drugs or preventive vaccines in the market. Therefore, it is necessary to develop a safe and effective anti-adenovirus type 7 vaccine. In this study, In this study, we used the baculovirus-insect cell expression system to design a recombinant subunit vaccine expressing adenovirus type 7 hexon protein (rBV-hexon) to induce high-level humoral and cellular immune responses. To evaluate the effectiveness of the vaccine, we first detected the expression of molecular markers on the surface of antigen presenting cells and the secretion of proinflammatory cytokines in vitro. We then measured the levels of neutralizing antibodies and T cell activation in vivo. The results showed that the rBV-hexon recombinant subunit vaccine could promote DC maturation and improve its antigen uptake capability, including the TLR4/NF-κB pathway which upregulated the expression of MHCI, CD80, CD86 and cytokines. The vaccine also triggered a strong neutralizing antibody and cellular immune response, and activated T lymphocytes. Therefore, the recombinant subunit vaccine rBV-hexon promoted promotes humoral and cellular immune responses, thereby has the potential to become a vaccine against HAdv-7.

Abstract 2999: Hippo signaling pathway regulates cancer-cell-intrinsic MHC-II expression in melanoma

Abstract MHC-II is known to be mainly expressed on the surface of antigen-presenting cells (APCs). Nevertheless, increasing evidence suggests that MHC-II is also expressed by solid tumor cancer cells and may be associated with better immunotherapy responses. However, the regulation of MHC-II in cancer cells remain unclear. In this study, we leveraged data mining and experimental validation to elucidate the regulation of MHC-II in cancer cells and its role in modulating the response to immunotherapy. We collated an extensive collection of omics data to examine the cancer-cell-intrinsic MHC-II expression and its association with immunotherapy outcomes. We then tested the functional relevance of cancer-cell-intrinsic MHC-II expression using a syngeneic transplantation model. Finally, we performed data mining to identify pathways potentially involved in the regulation of MHC-II expression, and experimentally validated candidate regulators. Comprehensive meta-analysis of multiomics data from an exhaustive collection of data revealed that MHC-II is heterogeneously expressed in various solid tumors, and its expression is particularly high in melanoma. Using a syngeneic transplantation model, we further established that melanoma cells with high MHC-II responded better to anti-PD-1 treatment. Data mining followed by experimental validation revealed the Hippo signaling pathway as a potential regulator of melanoma MHC-II expression. Citation Format: Shengqing Gu. Hippo signaling pathway regulates cancer-cell-intrinsic MHC-II expression in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2999.