Antigenic Peptides Research Articles

Tapasin assembly surveillance by the RNF185/Membralin ubiquitin ligase complex regulates MHC-I surface expression

Immune surveillance by cytotoxic T cells eliminates tumor cells and cells infected by intracellular pathogens. This process relies on the presentation of antigenic peptides by Major Histocompatibility Complex class I (MHC-I) at the cell surface. The loading of these peptides onto MHC-I depends on the peptide loading complex (PLC) at the endoplasmic reticulum (ER). Here, we uncovered that MHC-I antigen presentation is regulated by ER-associated degradation (ERAD), a protein quality control process essential to clear misfolded and unassembled proteins. An unbiased proteomics screen identified the PLC component Tapasin, essential for peptide loading onto MHC-I, as a substrate of the RNF185/Membralin ERAD complex. Loss of RNF185/Membralin resulted in elevated Tapasin steady state levels and increased MHC-I at the surface of professional antigen presenting cells. We further show that RNF185/Membralin ERAD complex recognizes unassembled Tapasin and limits its incorporation into PLC. These findings establish a novel mechanism controlling antigen presentation and suggest RNF185/Membralin as a potential therapeutic target to modulate immune surveillance.

Exploring the potential of structure-based deep learning approaches for T cell receptor design.

Deep learning methods, trained on the increasing set of available protein 3D structures and sequences, have substantially impacted the protein modeling and design field. These advancements have facilitated the creation of novel proteins, or the optimization of existing ones designed for specific functions, such as binding a target protein. Despite the demonstrated potential of such approaches in designing general protein binders, their application in designing immunotherapeutics remains relatively underexplored. A relevant application is the design of T cell receptors (TCRs). Given the crucial role of T cells in mediating immune responses, redirecting these cells to tumor or infected target cells through the engineering of TCRs has shown promising results in treating diseases, especially cancer. However, the computational design of TCR interactions presents challenges for current physics-based methods, particularly due to the unique natural characteristics of these interfaces, such as low affinity and cross-reactivity. For this reason, in this study, we explored the potential of two structure-based deep learning protein design methods, ProteinMPNN and ESM-IF1, in designing fixed-backbone TCRs for binding target antigenic peptides presented by the MHC through different design scenarios. To evaluate TCR designs, we employed a comprehensive set of sequence- and structure-based metrics, highlighting the benefits of these methods in comparison to classical physics-based design methods and identifying deficiencies for improvement.

Comprehensive bioinformatics assessments of the ROP34 of Toxoplasma gondii to approach vaccine candidates

IntroductionRhoptries proteins (ROPs) are crucial throughout different stages of the Toxoplasma gondii (T. gondii) lifecycle, playing key roles in both the invasion of host cells and their subsequent survival. ROP34 is particularly noteworthy as it significantly influences host gene expression and aids in the transition from the tachyzoite to the bradyzoite form.Materials and methodsThis research utilized various bioinformatics tools to assess physico-chemical properties, allergenic and antigenic characteristics, sites for post-translational modifications (PTMs) and protein's secondary and three-dimensional structures of the ROP34 protein. Furthermore, the study identified potential B-cell, MHC-binding, and cytotoxic T-lymphocyte (CTL) epitopes within the ROP34 sequence.ResultsThe ROP34 peptide comprised 553 amino acid residues, with a calculated average molecular weight (MW) of 61.60149 kDa, an aliphatic index of 73.98, and a GRAVY score of − 0.554. The antigenicity of the multi-epitope peptide was estimated to be 0.526563 and 0.6025 by the ANTIGENpro and VaxiJen servers, respectively, suggesting ROP34 as an immunogenic protein with no allergenic potential. Secondary structure analysis revealed a composition of 52.80% random coil, 36.17% alpha helix, and 11.03% extended strand. The Ramachandran plot for the refined model depicted that 97.46% of the residues were situated in the favored region.ConclusionThis in silico research serves as a foundation for designing effective immunization tactics to target toxoplasmosis. The present article lays the groundwork for future studies and offers perspectives for the advancement of an appropriate toxoplasmosis vaccine.Graphical

Immunoproteasome activation expands the MHC class I immunopeptidome, unmasks neoantigens and enhances T-cell antimyeloma activity.

Proteasomes generate antigenic peptides that are presented on the tumor surface to cytotoxic T-lymphocytes (CTLs). Immunoproteasomes are highly-specialized proteasome variants that are expressed at higher levels in antigen-presenting cells and contain replacements of the three constitutive proteasome catalytic subunits to generate peptides with a hydrophobic C-terminus that fit within the groove of MHC class I (MHC-I) molecules. A hallmark of cancer is the ability to evade immunosurveillance by disrupting the antigen presentation machinery and downregulating MHC-I antigen presentation. High-throughput screening was performed to identify Compound A, a novel molecule that selectively increased immunoproteasome activity and expanded the number and diversity of MHC-I-bound peptides presented on multiple myeloma (MM) cells. Compound A increased the presentation of individual MHC-I-bound peptides >100-fold and unmasked tumor-specific neoantigens on myeloma cells. Global proteomic integral stability assays determined that Compound A binds the proteasome structural subunit PSMA1 and promotes association of the proteasome activator PA28α/β (PSME1/PSME2) with immunoproteasomes. CRISPR/Cas9 silencing of PSMA1, PSME1, or PSME2 as well as treatment with immunoproteasome-specific suicide inhibitors abolished the effects of Compound A on antigen presentation. Treatment of MM cell lines and patient bone marrow-derived CD138+ cells with Compound A increased the antimyeloma activity of allogenic and autologous T-cells. Compound A was well-tolerated in vivo and co-treatment with allogeneic T-cells reduced the growth of myeloma xenotransplants in NSG mice. Taken together, our results demonstrate the paradigm-shifting impact of immunoproteasome activators to diversify the antigenic landscape, expand the immunopeptidome, potentiate T-cell-directed therapy, and reveal actionable neoantigens for personalized T-cell immunotherapy.

Antigenic peptide-tobacco mosaic virus conjugates as a fungal vaccine candidate

Fungal infections are becoming an increasingly serious challenge in clinic due to the increase in drug resistance and the lack of anti-fungal drugs. Vaccination is a useful approach to prevent fungal infections. However, the balance between effectiveness and side effects presents a challenge in vaccine development. In this work, we designed a plant virus-based conjugate vaccine. The non-infectiveness and innate immunogenicity of plant viruses make this vaccine both safe and effective. By conjugating a fungal antigenic peptide to the tobacco mosaic virus (TMV), the resultant vaccine improved the uptake efficiency of antigenic peptides by antigen-presenting cells and enhanced the ability to target lymph nodes. The results of in vivo vaccination in mice showed a significant increase of antigen-specific IgG antibody levels induced by the TMV conjugate vaccine. This work suggests that TMV conjugate vaccines may become a potential vaccine candidate for preventing fungal infections.

Carbohydrate-Lectin Interactions Reprogram Dendritic Cells to Promote Type 1 Anti-Tumor Immunity.

Cancer vaccine development is inhibited by a lack of strategies for directing dendritic cell (DC) induction of effective tumor-specific cellular immunity. Pathogen engagement of DC lectins and toll-like receptors (TLRs) is thought to shape immunity by directing T cell function. Controlling downstream responses, however, remains a major challenge. A critical goal in advancing vaccine development involves the identification of receptors that drive type 1 cellular immunity. The immune system monitors cells for aberrant glycosylation (a sign of a foreign entity), but potent activation occurs when a second signal, such as single-stranded RNA or lipopolysaccharide, is present to activate TLR signaling. To exploit dual signaling, we engineered a glycan-costumed virus-like particle (VLP) vaccine that displays a DC-SIGN-selective aryl mannose ligand and encapsulates TLR7 agonists. These VLPs deliver programmable peptide antigens to induce robust DC activation and type 1 cellular immunity. In contrast, VLPs lacking this critical DC-SIGN ligand promoted DC-mediated humoral immunity, offering limited tumor control. Vaccination with glycan-costumed VLPs generated tumor antigen-specific Th1 CD4+ and CD8+ T cells that infiltrated solid tumors, significantly inhibiting tumor growth in a murine melanoma model. The tailored VLPs also afforded protection against the reintroduction of tumor cells. Thus, DC lectin-driven immune reprogramming, combined with the modular programmability of VLP platforms, provides a promising framework for directing cellular immunity to advance cancer immunotherapies and vaccines.

Antigenic peptide–thioredoxin fusion chimeras for <i>in vitro</i> stimulus of CD4<sup>+</sup> TCR<sup>+</sup> Jurkat T-cells

Study of CD4+ T-cell response and T-cell receptor (TCR) specificity is crucial for understanding etiology of immune-mediated diseases and developing targeted therapies. However, solubility, accessibility, and stability of synthetic antigenic peptides used in T-cell assays may be a critical point in such studies. Here we present a T-cell activation reporter system using recombinant proteins containing antigenic epitopes fused with bacterial thioredoxin (trx-peptides) and obtained by bacterial expression. We report that co-incubation of CD4+ HA1.7 TCR+ reporter Jurkat 76 TRP-cells with CD80+ HLA-DRB1*01:01+ HeLa-cells or CD4+ Ob.1A12 TCR+ Jurkat 76 TRP with CD80+ HLA-DRB1*15:01+ HeLa-cells resulted in activation of reporter Jurkat 76 TPR after addition of recombinant trx-peptide fusion proteins, containing TCR-specific epitopes. Trx-peptides were comparable with corresponding synthetic peptides in their capacity to activate Jurkat 76 TPR. These data demonstrate that thioredoxin as a carrier protein (trx) for antigenic peptides exhibits minimal interference with recognition of MHC-specific peptides by TCRs and consequent T-cell activation. Our findings highlight potential feasibility of trx-peptides as a reagent for assessing the immunogenicity of antigenic fragments.

Abstract B063: Elucidating treatment induced tumor antigen presentation in pancreatic cancer

Abstract Introduction Pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, is projected to become the second leading cause of cancer-related deaths by 2030. The 5-year survival rate remains stubbornly low at just 13%. These discouraging statistics primarily stem from the lack of effective treatments till date. Despite the success of immunotherapy for several malignancies, immunotherapy for PDAC has yielded disappointing results alone or in combination with other therapies. Successful immunotherapy will require a deeper understanding of PDAC immunobiology and immune recognition of cancer during its progression, and treatment regimens. Immunosurveillance of cancer requires the presentation of peptide antigens on Major Histocompatibility complex class I (MHC-I). Understanding the repertoire of MHC-I associated peptides (pMHC-I), collectively termed as the “immunopeptidome”, is essential for anti-tumor immunity and successful immunotherapies. Using a collection of preclinical tools and human cell lines, we aim to uncover treatment induced antigens in PDAC that can be used for targeted immunotherapy approaches. Methods To understand the biogenesis of the immunopeptidome, our group has developed a novel genetically engineered mouse model (GEMM), which integrates inducible affinity tags on MHC-I (KbStrep) and ribosomes (RiboTag) into the Kras LSL-G12D/+ ; P53 fl/fl (KP) mouse model (KP/RiboMHC). This approach enabled us to precisely measure protein synthesis and antigen presentation in malignant PDAC cells in vivo with paired ribosome profiling and mass spectrometry based immunopeptidomics. In parallel we have employed a collection of human PDAC cell lines for immunopeptidomics analysis. About 93% of PDACs have KRAS mutation, with G12D mutation being the most common. In addition, PDAC is subjected to a deregulated metabolic milieu, with a strong dependence on glutamine utilization. Therefore, to examine treatment induced changes in PDAC antigen presentation, we examined the impact of KRAS inhibition (MRTX1133) and glutamine antagonism (6-diazo-5-oxo-L-norleucine, DON) on the biogenesis of the immunopeptidome in vitro and in vivo. Results Using our GEMM model, we have started to uncover MRTX1133 and DON induced alterations in protein synthesis and in pMHC-I repertoire in vivo using the KP/RiboMHC model and in vitro in mouse and human cell lines. We have identified unique antigen peptides that are induced by MRTX1133 and DON, including those derived from non-canonical translation events that were defined by ribosome profiling. Conclusions Our data demonstrates that KRAS inhibition with MRTX1133 or glutamine antagonism with DON reshapes the antigen landscape of PDAC. We are actively exploring which of the induced peptides harbor potential to mount an anti-tumor CD8+ T cell response. Collectively, these results could pave the way forward for rationally designed treatment regimens that pair targeted therapies with antigen specific immunotherapy in PDAC. Citation Format: Emma Adhikari, Andrew Weeden, Emily Brennan, Christopher Polera, Victoria lzumi, Bin Fang, John Koomen, Paul Stewart, Alex Jaeger. Elucidating treatment induced tumor antigen presentation in pancreatic cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr B063.

UT-1 Transporter Expression in the Spiny Dogfish (Squalus acanthias): UT-1 Protein Shows a Different Localization in Comparison to That of Other Sharks.

The original UT-1 transporter gene was initially identified in the spiny dogfish (Squalus acanthias), but localization of the UT-1 protein was not determined. Subsequent UT-1 expression was shown to localize to the collecting tubule (CT) of the shark nephron in other shark species, with expression in a closely related chimaera species also located additionally at a lower level in the intermediate-I segment (IS-I) of the nephron. In spiny dogfish, two UT-1 splice variants are known (UT-1 long and short), and there was also a second UT-1 gene described (here termed Brain UT). In this study, a second splice variant of the second Brain UT gene was discovered. Expression profiles (mRNA) of UT-1 long and short and Brain UT were determined in a number of spiny dogfish tissues. Quantitative PCR in kidney samples showed that the level of the short variant of UT-1 was around 100 times higher than the long variant, which was itself expressed around 10 times higher than Brain UT cDNA/mRNA (in kidney). For the long variant, there was a significantly higher level of mRNA abundance in fish acclimatized to 75% seawater. Ultimately, three UT-1 antibodies were made that could bind to both the UT-1 short and long variant proteins. The first two of these showed bands of appropriate sizes on Western blots of around 52.5 and 46 kDa. The second antibody had some additional lower molecular weight bands. The third antibody was mainly bound to the 46 kDa band with faint 52.5 kDa staining. Both the 52.5 and 46 kDa bands were absent when the antibodies were pre-blocked with the peptide antigens used to make them. Across the three antibodies, there were many similarities in localization but differences in subcellular localization. Predominantly, antibody staining was greatest in the intermediate segment 1 (IS-I) and proximal (PIb) segments of the first sinus zone loop of the nephron, with reasonably strong expression also found at the start and middle of the late distal tubule (LDT; second sinus zone loop). While some expression in the collecting tubule (CT) could not be ruled out, the level of staining seemed to be low or non-existent in convoluted bundle zone nephron segments such as the CT. Hence, this suggests that spiny dogfish have a fundamentally different mode of urea absorption in comparison to that found in other shark species, potentially focused more on the nephron sinus zone loops than the CT.

Global awareness of antigenic peptides - Unraveling the impact on sickle cell anemia patients in the presence of pathogens: A narrative review.

Sickle cell anemia (SCA) is a genetic blood disorder characterized by the production of abnormal hemoglobin S (HbS), leading to sickle-shaped red blood cells and various complications, including increased susceptibility to infections. The presence of antigenic peptides, short amino acid sequences derived from pathogens or altered self-proteins, plays a crucial role in immune responses. This review explores the global awareness of antigenic peptides, their role in immune responses in SCA patients, and the challenges and opportunities in managing infections within this vulnerable population. Antigenic peptides are central to the adaptive immune response, facilitating the recognition and elimination of pathogens by T-cells. In SCA, altered antigen presentation and impaired T-cell responses due to chronic inflammation, functional asplenia, and ongoing hemolysis contribute to increased susceptibility to infections. Pathogens such as Streptococcus pneumoniae and Haemophilus influenzae pose significant risks to SCA patients, highlighting the importance of robust immune responses mediated by antigenic peptides. Strategies such as vaccination and immunotherapy aim to enhance immune function by targeting specific antigenic peptides, thereby reducing infection rates and improving patient outcomes. Advances in genomics and proteomics offer insights into individual variations in antigen presentation and immune responses, guiding the development of tailored therapeutic interventions. Global collaborations are essential to address disparities in healthcare access and implement effective preventive measures, ensuring equitable outcomes for SCA patients worldwide.

A case of mixed neuroendocrine carcinoma-acinar adenocarcinoma: Utilization of triplet therapy for prostate cancer.

Neuroendocrine prostate cancer is an aggressive histological subtype of prostate cancer with a poor prognosis. Neuroendocrine prostate cancer is traditionally treated with cisplatin-based chemotherapy, similar to that used in treating small-cell lung cancer. However, the therapeutic effectiveness of chemotherapy for neuroendocrine prostate cancer has been limited. This case report describes a response to triplet therapy using darolutamide, androgen deprivation therapy, and docetaxel, which was administered in a patient with mixed neuroendocrine prostate cancer. A 77-year-old man was newly diagnosed with mixed neuroendocrine prostate cancer. Serum prostate-specific antigen, neuron-specific enolase, and progastrin-releasing peptide levels were 62.2, 40.6, and 60.6 pg/mL, respectively. Multiple lymph node metastases were identified on a computed tomography scan, and bone scintigraphy revealed multiple bone metastases. The clinical stage was determined to be cT3bN1M1b. Ultimately, tumor size and serum markers decreased with triplet therapy. We demonstrated the first case in which triplet therapy had been effective in the treatment of neuroendocrine prostate cancer.

Stabilization of the open conformation οf insulin-regulated aminopeptidase by a novel substrate-selective small-molecule inhibitor.

Insulin-regulated aminopeptidase (IRAP) is an enzyme with important biological functions and the target of drug-discovery efforts. We combined in silico screening with a medicinal chemistry optimization campaign to discover a nanomolar inhibitor of IRAP based on a pyrazolylpyrimidine scaffold. This compound displays an excellent selectivity profile versus homologous aminopeptidases, and kinetic analysis suggests it utilizes an uncompetitive mechanism of action when inhibiting the cleavage of a typical dipeptidic substrate. Surprisingly, the compound is a poor inhibitor of the processing of the physiological cyclic peptide substrate oxytocin and a 10mer antigenic epitope precursor but displays a biphasic inhibition profile for the trimming of a 9mer antigenic peptide. While the compound reduces IRAP-dependent cross-presentation of an 8mer epitope in a cellular assay, it fails to block in vitro trimming of select epitope precursors. To gain insight into the mechanism and basis of this unusual selectivity for this inhibitor, we solved the crystal structure of its complex with IRAP. The structure indicated direct zinc(II) engagement by the pyrazolylpyrimidine scaffold and revealed that the compound binds to an open conformation of the enzyme in a pose that should block the conformational transition to the enzymatically active closed conformation previously observed for other low-molecular-weight inhibitors. This compound constitutes the first IRAP inhibitor targeting the active site that utilizes a conformation-specific mechanism of action, provides insight into the intricacies of the IRAP catalytic cycle, and highlights a novel approach to regulating IRAP activity by blocking its conformational rearrangements.

Identification of endoplasmic reticulum stress-associated genes and subtypes for predicting risk signature and depicting immune features in inflammatory bowel disease

Endoplasmic reticulum stress (ERS) becomes a significant factor in inflammatory bowel disease (IBD), like Crohn's disease (CD) and ulcerative colitis (UC). Our research was aimed at identifying molecular markers to enhance our understanding of ERS and inflammation in IBD, recognizing risk factors and high-risk groups at the molecular level, and developing a predictive model on the grounds of based on ERS-associated genes.This research adopted the least absolute shrinkage and selection operator (LASSO) regression and logistic regression to build a predictive model, and categorized IBD patients into high- and low-risk groups, and then identified four gene clusters. Our key findings included a significant increase in drug target gene expression in high-risk groups, notable discrepancies in immune levels, and functions between high-risk and low-risk groups. Notably, the TAP1 gene emerged as a strong predictor with the highest diagnostic value (area under the curve [AUC] = 0.941). TAP1 encodes proteins required for antigenic peptide transfer across the endoplasmic reticulum (ER) membrane, and its potential as a diagnostic marker and therapeutic target is reflected by its overexpression in IBD tissues.Our study established a new ERS-associated gene model which could forecast the risk, immunological status, and treatment efficacy of patients with IBD. These findings suggest potential targets for personalized therapy and highlight the significance of ERS in the etiology and therapy of IBD. Future studies should explore the therapeutic potential of targeting TAP1 and other ERS-related genes for IBD management.

Abstract P389: Immunogenic Peptides Responsible for Experimental Hypertension Contribute to Systemic Lupus Erythematosus

Introduction: Hypertension and systemic lupus erythematosus (SLE) lead to modification of self-peptides by isolevuglandin (isoLG) lipid oxidation products. These self-peptides are presented by class 1 major histocompatibility complexes and drive CD8 + T cell activation. We have identified self-peptides from the sodium/glucose cotransporter2 (SGLT2); cadherin 16; Kelch domain-containing protein 7A and solute carrier family 23 that are IsoLG-adducted and cause CD8 + T cell activation in both ang II and L-NAME/high salt models of hypertension. These prime hypertension in response to low dose ang II. Hypothesis: We hypothesized that the same immunogenic peptides responsible for experimental hypertension contribute to systemic lupus erythematosus. Methods: A fluorescent probe made of recombinant IgG and the murine class 1 MHC H2-D b was loaded with either unadducted SGLT2 peptide or an isoLG-adducted SGLT2 peptide. This probe was used in flow cytometry to detect CD8 + T cells specific for this peptide antigen in 12-week-old C57Bl/6 and female B6SLE1.2.3 mice. Results: The unadducted SGLT2 probe recognized < 1% of CD8 + T cells (Figure). In contrast, ang II-infusion caused a striking increase in IsoLG-SGLT2 specific CD8 + T cells in C57Bl/6 aortas (Figure panels A and D). In C57Bl/6 very few CD8 + T cells recognizing IsoLG-SGLT2 were observed in the spleen (Panel B and E). Importantly, from 5 to 20% of CD8 + T cells in spleens of female B6SLE1.2.3 mice recognized the IsoLG-SGLT2 peptide (Figure panels C and E). Image 1. Conclusions: These findings strongly suggest that IsoLG-adducted peptides responsible for ang II-induced hypertension contribute to SLE and suggest that these conditions share similar immunogenicity.

Molecular and Evolutionary Characteristics of Chicken Parvovirus (ChPV) Genomes Detected in Chickens with Runting-Stunting Syndrome.

Chicken Parvovirus (ChPV) belongs to the genus Aveparvovirus and is implicated in enteric diseases like runting-stunting syndrome (RSS) in poultry. In RSS, chicken health is affected by diarrhea, depression, and increased mortality, causing significant economic losses in the poultry industry. This study aimed to characterize the ChPV genomes detected in chickens with RSS through a metagenomic approach and compare the molecular and evolutionary characteristics within the Aveparvovirus galliform1 species. The intestinal content of broiler flocks affected with RSS was submitted to viral metagenomics. The assembled prevalent genomes were identified as ChPV after sequence and phylogenetic analysis, which consistently clustered separately from Turkey Parvovirus (TuPV). The strain USP-574-A presented signs of genomic recombination. The selective pressure analysis indicated that most of the coding genes in A. galliform1 are evolving under diversifying (negative) selection. Protein modeling of ChPV and TuPV viral capsids identified high conservancy over the VP2 region. The prediction of epitopes identified several co-localized antigenic peptides from ChPV and TuPV, especially for T-cell epitopes, highlighting the immunological significance of these sites. However, most of these peptides presented host-specific variability, obeying an adaptive scenario. The results of this study show the evolutionary path of ChPV and TuPV, which are influenced by diversifying events such as genomic recombination and selective pressure, as well as by adaptation processes, and their subsequent immunological impact.

A Minimalist Pathogen-Like Sugar Nanovaccine for Enhanced Cancer Immunotherapy.

Pathogen-mimicking nanoparticles have emerged at the forefront of vaccine delivery technology, offering potent immune activation and excellent biocompatibility. Among these innovative carriers, mannan, a critical component of yeast cell walls, shows promise as an exemplary vaccine carrier. Nevertheless, it faces challenges like unpredictable immunogenicity, rapid elimination, and limited antigen loading due to high water solubility. Herein, mannan with varying carbon chain ratios is innovatively modified, yielding a series of dodecyl chains modified mannan (Mann-C12). Through meticulous screening, a mannan variant with a 40% grafting ratio is pinpointed as the optimal vaccine carrier. Further RNA sequencing confirms that Mann-C12 exhibits desired immunostimulatory characteristics. Coupled with antigen peptides, Mann-C12/OVA257-280 nanovaccine initiates the maturation of antigen-presenting cells by activating the TLR4 and Dectin-2 pathways, significantly boosting antigen utilization and sparking antigen-specific immune responses. In vivo, experiments utilizing the B16-OVA tumor model underscore the exceptional preventive capabilities of Mann-C12/OVA257-280. Notably, when combined with immune checkpoint blockade therapy, it displays a profound synergistic effect, leading to marked inhibition of tumor growth. Thus, the work has yielded a pathogen-like nanovaccine that is both simple to prepare and highly effective, underscoring the vast potential of mannan-modified nanovaccines in the realm of cancer immunotherapy.

Non-HIV Vaccine-Induced Immune Responses as Potential Baseline Immunogenicity Predictors of ALVAC-HIV and AIDSVAX B/E-Induced Immune Responses.

Identifying correlations between immune responses elicited via HIV and non-HIV vaccines could aid the search for correlates of HIV protection and increase statistical power in HIV vaccine-efficacy trial designs. An exploratory objective of the HVTN 097 phase 1b trial was to assess whether immune responses [focusing on those supported as correlates of risk (CoR) of HIV acquisition] induced via the RV144 pox-prime HIV vaccine regimen correlated with those induced via tetanus toxoid (TT) and/or hepatitis B virus (HBV) vaccines. We measured TT-specific and HBV-specific IgG-binding antibody responses and TT-specific and HBV-specific CD4+ T-cell responses at multiple time points in HVTN 097 participants, and we assessed their correlations at peak time points with HIV vaccine (ALVAC-HIV and AIDSVAX B/E)-induced responses. Four correlations were significant [false discovery rate-adjusted p-value (FDR) ≤ 0.2]. Three of these four were with IgG-binding antibody responses to TT measured one month after TT receipt, with the strongest and most significant correlation [rho = 0.368 (95% CI: 0.096, 0.588; p = 0.008; FDR = 0.137)] being with IgG-binding antibody responses to MN gp120 gDneg (B protein boost) measured two weeks after the second ALVAC-HIV and AIDSVAX B/E boost. The fourth significant correlation [(rho = 0.361; 95% CI: 0.049, 0.609; p = 0.021; FDR = 0.137)] was between CD4+ T-cell responses to a hepatitis B surface antigen peptide pool, measured 2 weeks after the third HBV vaccination, and IgG-binding antibody responses to gp70BCaseAV1V2 (B V1V2 immune correlate), measured two weeks after the second ALVAC-HIV and AIDSVAX B/E boost. These moderate correlations imply that either vaccine, TT or HBV, could potentially provide a moderately useful immunogenicity predictor for the ALVAC-HIV and AIDSVAX B/E HIV vaccine regimen.

IVAC-XS15-CLL01: personalized multi-peptide vaccination in combination with the TLR1/2 ligand XS15 in CLL patients undergoing BTK-inhibitor-based regimens.

Chronic lymphocytic leukemia (CLL) is the most common form of leukemia among adults in Western countries. Despite the introduction of targeted therapies, including first-line Bruton's tyrosine kinase inhibitor (BTKi) treatment, CLL remains largely incurable. Frequent disease relapses occur due to remaining treatment-resistant CLL cells, calling for novel therapies to eliminate minimal residual disease (MRD). Peptide-based vaccination targeting human leucocyte antigen (HLA)-presented CLL-associated antigens represents a promising, low-side-effect therapeutic option to optimize treatment responses and eliminate residual tumor cells by inducing an anti-leukemic immune response. The iVAC-XS15-CLL01 trial is an open-label, first-in-human (FIH) Phase I trial, evaluating the CLL-VAC-XS15 vaccine in CLL patients undergoing BTKi-based therapy. The vaccine was developed from HLA-presented CLL-associated antigen peptides, identified through comparative mass-spectrometry-based immunopeptidome analyses of CLL versus healthy samples in a previous study. To facilitate rapid and cost-effective deployment, vaccine peptides are selected for each patient from a pre-manufactured "peptide warehouse" based on the patient's individual HLA allotype and CLL immunopeptidome. The trial enrolls 20 CLL patients, who receive up to three doses of the vaccine, adjuvanted with the toll-like-receptor (TLR) 1/2 ligand XS15 and emulsified in Montanide ISA 51 VG. The primary objective of the iVAC-XS15-CLL01 trial is to assess the safety and immunogenicity of the CLL-VAC-XS15 vaccine. Secondary objectives are to evaluate the vaccine impact on MRD, progression-free survival, and overall survival, as well as comprehensive immunophenotyping to characterize vaccine-induced T-cell responses. This Phase I trial aims to advance CLL treatment by enhancing immune-mediated disease clearance and guiding the design of subsequent Phase II/III trials to implement a new therapeutic strategy for CLL patients.

A SARS-CoV-2 peptide antigen purified from bacteria and displayed in a high-density repetitive manner on a virus-like particle could generate anti-SARS-CoV-2 neutralizing antibodies unlike free peptide

SARS-CoV-2 is an enveloped virus. Proteins of the lipid based envelope are not rigidly arranged as compared to non-enveloped viruses lacking lipid based outer layer. Rigidly arranged multivalent display has been reported to be important for potent immune stimulation. We assembled himeric virus-like-particle (VLP) where the core of the particle is composed of the coat protein of Acinetobacter phage. Peptide-based antigen from receptor binding domain (RBD) of SARS-CoV-2 spike protein has been displayed on the coat based VLP matrix using spy-tag/spy-catcher split inteine conjugation system that allows spontaneous, irreversible isopeptide bond formation. Both the matrix as well as peptide have been purified from bacteria which is an easy platform for protein purification. We used the closed state of spike trimer for epitope mapping as this is the conformation of the spike that the immune system visualizes unlike the open state that appears when the virus tries to attach to receptor. Mice based immunization studies were used to test immunogenicity of the antigens. The work demonstrates that peptide-based antigens displayed in high densities can induce neutralizing antibody production unlike free peptide. Careful choice of peptides can deliver better candidates. Also, small size allows easy improvisation. Production in bacteria offers cheaper and robust purification option.

Posttranslationally modified self-peptides promote hypertension in mouse models.

Posttranslational modifications can enhance immunogenicity of self-proteins. In several conditions, including hypertension, systemic lupus erythematosus, and heart failure, isolevuglandins (IsoLGs) are formed by lipid peroxidation and covalently bond with protein lysine residues. Here, we show that the murine class I major histocompatibility complex (MHC-I) variant H-2Db uniquely presents isoLG-modified peptides and developed a computational pipeline that identifies structural features for MHC-I accommodation of such peptides. We identified isoLG-adducted peptides from renal proteins, including sodium glucose transporter 2, cadherin 16, Kelch domain-containing protein 7A, and solute carrier family 23, that are recognized by CD8+ T cells in tissues of hypertensive mice, induce T cell proliferation in vitro, and prime hypertension after adoptive transfer. Finally, we find patterns of isoLG-adducted antigen restriction in class I human leukocyte antigens that are similar to those in murine analogs. Thus, we have used a combined computational and experimental approach to define likely antigenic peptides in hypertension.