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PubMed2026

A transient, B cell-targeted tolerance switch using nanoparticles loaded with metabolizable AhR agonists for antigen-specific immune regulation.

Achieving antigen-specific immune tolerance without systemic immunosuppression remains a major challenge in biomaterial-based immunotherapy. Here, we report a simple nanoparticle (NP)-based platform that enables a transient, B cell-targeted tolerance switch. NPs encapsulating metabolizable aryl hydrocarbon receptor (AhR) agonists-FICZ or ITE-preferentially accumulate in splenic marginal zone B cells and convert them into IL-10-producing regulatory B cells (Bregs). This study provides the first in vivo evidence that Bregs can directly present antigen and induce regulatory T cells (Tregs), establishing a NP-controlled Breg-Treg pathway. These Bregs promote antigen-specific Tregs expansion only when co-exposed to antigen, establishing time-gated, antigen-restricted immune regulation. By exploiting the rapid metabolism of AhR agonists, this system provides precise temporal control of tolerance induction while preserving vaccine responses. In mouse models, co-administration of FICZ-containing NP with antigen suppressed anti-drug antibody formation and ameliorated allergic inflammation. This NP platform demonstrates a strategy for safe, antigen-specific immunomodulation and offers a clinically adaptable framework for allergy and biotherapeutic tolerance.

Animals↗

PubMed2025

Tonic signaling of the B-cell antigen-specific receptor is a common functional hallmark in chronic lymphocytic leukemia cell phosphoproteomes at early disease stages.

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by highly heterogeneous genomic alterations and altered signaling pathways, with limited studies on its proteome. Our study presents a comprehensive analysis of the proteome and phosphoproteome in B-CLL and CLL-like monoclonal B-cell lymphocytosis (MBL) primary cells. Using high-resolution mass spectrometry, we identified 2970 proteins and 316 phosphoproteins across five tumor samples, including 55 newly identified phosphopeptides (ProteomeXchange-PXD005997). Our multifaceted approach also integrated protein microarrays and western blotting for further data validation in a new patient cohort of 14 patients. Despite sharing 73% of their proteomes, the phosphoproteomes varied significantly among samples, independent of cytogenetic alterations and immunoglobulin heavy variable cluster (IGHV) mutational status. We identified common functional hallmarks in B-CLL and MBL phosphoproteomes, notably tonic signaling (low-level, constitutive signaling) of the B-cell antigen-specific receptor (BCR) and nuclear factor NF-kappa-B (NF-kβ)/signal transducer and activator of transcription 3 (STAT3) pathways. Nine phosphoproteins involved in BCR signaling were further validated, showing a high correlation with early disease stages. Our study advances the field by providing a detailed perspective on the proteome and phosphoproteome of B-CLL cells, revealing signaling pathways crucial for disease development and progression. Integrating diverse proteomics techniques and identifying novel phosphopeptides offers new insights into CLL biology, potentially informing future therapeutic strategies and biomarker development for early diagnosis and personalized treatment.

Humans↗

PubMed2026

Intestinal infections establish antigen-specific, long-lived memory CD4+ T cells in the brain and meninges.

The meninges form the border between the brain and periphery and house a rich network of immune cells. Here we show that gastrointestinal challenges (intracellular or extracellular bacteria and parasites) reshape the nature of CD4+ T cells in the dura mater, the outer meningeal layer, changing the dominant polarization states to T helper (TH) 1, TH17 and TH2 cells, respectively, with differing cytokine profiles. This occurs via CXCR6-CXCL16-dependent migration of gut-activated CD4+ T cells to the central nervous system, where they establish long-lived memory populations around the dural venous sinuses, within dural lymphoid aggregates and in the brain. Functionally, these orally primed dural CD4+ T were capable of rapid, antigen-specific recall responses, proliferating and producing cytokines upon intravenous rechallenge. Our findings reveal a direct link between intestinal and dural immunity, enabling the central nervous system borders to acquire immunological memory of gut microorganisms, a major source of bloodborne pathogens capable of reaching the brain via fenestrated dural vasculature.

Journal Article↗

PubMed2026

First-in-human use of recombinant IL-7 to potentiate antigen-specific T cell therapy: a single patient case study.

Clinical trials of adoptive cellular therapy demonstrate that a key characteristic associated with durable responses is in vivo expansion and persistence of transferred T cells. Strategies to develop a less differentiated, stem/memory population in the infusion product and peri-infusional regimens to promote the maintenance of desired T cell states following adoptive transfer would be desirable. Endogenous T cell therapy studies have routinely achieved memory T cells enriched for expression of interleukin (IL)-7 receptor; to eliminate the conventional requirement for immunosuppressive lymphodepletion and its attendant life-threatening toxicities, we performed the first-in-human use of IL-7 in combination with adoptively transferred antigen-specific memory CD8 T cells in a patient with refractory metastatic uveal melanoma. Single-cell immune repertoire profiling of serial peripheral blood sampling revealed substantial in vivo proliferation and expansion of a stem cell memory population in the endogenous T cell therapy product that achieved a >79% predominance of total circulating T cells by 3 weeks post-infusion in this non-lymphodepleted recipient. Although the patient's disease ultimately progressed, these findings demonstrate safety and proof of concept for an IL-7 treatment regimen for expansion of adoptively transferred T cells in vivo and induced memory differentiation in a heavily pretreated patient with refractory solid malignancy.

Humans↗

PubMed2025

Substitution of Glutamic Acid at Position 71 of DRβ1*04:01 and Collagen-Specific Tolerance Without Alloreactivity.

OBJECTIVE: The DRB1 locus is strongly associated with both susceptibility and resistance to rheumatoid arthritis (RA). DRB1 alleles encoding the VKA or VRA epitope in positions 11, 71, and 74 confer the highest risk of developing RA, whereas the allele encoding VEA is protective. We therefore investigated the feasibility of creating antigen-specific tolerance without inducing alloreactivity by replacing lysine with glutamic acid at position 71 in DRβ1*04:01. METHODS: Individual DRB1 alleles and the DRB1*04:01K71E allele were cloned into T2 cell lines to measure binding of biotinylated peptides. Transgenic animals expressing DRB1*04:01, DRB1*01:01, or DRB1*04:01K71E were injected with collagen to measure T cell proliferation. Skin and bone marrow transplants between DRB1*04:01K71E and DRB1*04:01 mice were performed to determine if the single amino acid change at position 71 would be recognized as foreign. DRB1*04:01 mice transplanted with DRB1*04:01K71E bone marrow were injected with collagen to test if resistance to collagen sensitization could be transferred. RESULTS: Replacing lysine (K) at position 71 in DRβ1*04:01 with glutamic acid (E) blocked collagen peptide binding and rendered the DRB1*04:01K71E mice resistant to collagen sensitization. Skin and bone marrow transplants from DRB1*04:01K71E mice were not rejected by DRB1*04:01 mice, suggesting the single E71 difference was not recognized as allogeneic. Bone marrow from DRB1*04:01K71E mice adoptively transferred antigen-specific tolerance to collagen to DRB1*04:01 mice. CONCLUSION: These studies demonstrate that editing a single amino acid in DRβ1*04:01 blocks collagen peptide binding without inducing alloreactivity and could therefore represent a gene therapy approach to induce antigen-specific passive tolerance.

Animals↗

PubMed2026

The future of TCR-Treg therapies is renewables.

Cell therapy has longstanding roots in haematopoietic stem cell transplantation and early immune cell transfers in infectious disease and transplantation, where patient- or donor-derived cells have achieved therapeutic benefit in selected contexts. The modern era has been driven largely by oncology, with engineered modalities such as tumour-infiltrating lymphocytes, CAR-T cells and TCR-engineered T cells delivering transformative responses but requiring complex, costly manufacturing. These platforms are now being adapted for autoimmune diseases to induce durable, antigen-specific immune tolerance, yet broad application is limited by safety concerns, process complexity and access. Non-engineered cell therapies for autoimmunity, including mesenchymal stem cells, polyclonal regulatory T cells and tolerogenic dendritic cells, have shown acceptable safety and proof-of-principle for immune re-education, but clinical responses have been modest and inconsistent, with limited scalability. Engineered approaches such as CAR-T cells can induce reversible B cell depletion in B cell-mediated rheumatic diseases but only addresses antibody-driven pathology and not T cell-mediated autoimmunity. TCR-engineered Tregs have emerged as a promising antigen-specific strategy, offering localized, antigen-linked suppression with bystander tolerance. Preclinical and early clinical data suggest superior potency, stability and disease control compared with polyclonal Tregs at similar or lower doses, but translation is constrained by the rarity and fragility of Tregs and by labour-intensive, CAR-T-like manufacturing. This review highlights emerging solutions for closed, automated and decentralised production, and discusses allogeneic approaches using gene-edited or banked Tregs with HLA engineering or matching. Together, these advances support the development of scalable, "off-the-shelf" TCR-Treg products with potential to provide safe, affordable tolerance-restoring therapies for autoimmune disease.

Humans↗

PubMed2026

Evaluation of transduction properties and vaccine efficacy of a simian adenovirus type 25-based vector.

Although human adenovirus serotype 5 (Ad5) is widely used as a vaccine vector for infectious diseases due to its high transduction efficiency, pre-existing immunity to Ad5 in many people reduces vaccine efficacy. To address this limitation, simian Ad vectors, such as ChAdOx1 and ChAdOx2, have been explored as alternative vaccine platforms. ChAdOx2 is based on simian Ad25 (SAd25), but the fundamental characteristics of gene transduction by SAd25-based vectors have not been fully elucidated. This study aimed to characterize the gene transduction efficiency, tissue distribution, and immunogenicity of an SAd25-based vector in comparison with those of the Ad5 vector following various routes of administration. Compared with intravenous administration of the Ad5 vector, intravenous administration of the SAd25 vector showed distinct biodistribution patterns, including reduced liver accumulation and predominant expression in the lung. Transduction by the SAd25 vector was not inhibited by human serum, whereas transduction by the Ad5 vector was inhibited, indicating that the SAd25 vector, but not the Ad5 vector, can evade pre-existing Ad immunity. Although intramuscular administration of the SAd25 vector induced lower transgene product-specific antibody production than intramuscular administration of the Ad5 vector, gene expression and Ad genome distribution mediated by the SAd25 vector, but not the Ad5 vector, were localized only to the muscle at the administration site. Intranasal administration of the SAd25 vector induced an antigen-specific antibody response in serum more rapidly than intranasal administration of the Ad5 vector. The SAd25 vector induced antigen-specific antibody production in bronchoalveolar lavage fluid (BALF) that was comparable to that induced by the Ad5 vector. These findings provide essential insights into the biological characteristics of the SAd25 vector, supporting its potential as a safe and effective vaccine vector.

Animals↗

PubMed2026

mRNA vaccine immunity is enhanced by hepatocyte detargeting and not dependent on dendritic cell expression.

Proteins encoded by mRNA vaccines can be expressed by a diversity of transfected cell types but how cell-type-specific expression influences immunity is poorly understood. To investigate this, we incorporated synthetic microRNA target sites (miRT) into lipid nanoparticle (LNP)-delivered mRNA vaccines to silence mRNA expression specifically in professional antigen-presenting cells (pAPCs), hepatocytes or myocytes. We found that mRNA expression in pAPCs was dispensable for priming antigen-specific T cells, whereas mRNA expression in myocytes induced similar or stronger immune responses, including for SARS-CoV-2, suggesting that antigen cross-presentation or cross-dressing may be more impactful than direct mRNA expression in pAPCs. In contrast, mRNA expression in hepatocytes suppressed the antigen-specific T cell response, partly through PD1/PDL1. In mice bearing tumor-associated antigen (TAA)-expressing lymphoma cells, miRT-mediated hepatocyte-silenced TAA mRNA vaccine enhanced immune response and reduced tumor burden. Thus, non-pAPC expression shapes immunity to mRNA-encoded protein and inclusion of miRTs can boost or blunt mRNA-LNP immunogenicity.

Journal Article↗

PubMed2026

Clonal stochasticity in early NK cell response to mouse cytomegalovirus is generated by mature subsets of varying proliferative ability.

Natural killer (NK) cells are classically defined as innate immune cells, but experiments show that mouse cytomegalovirus (MCMV) infection in C57BL/6 mice can cause NK cells to undergo antigen-specific proliferation and memory formation, similar to adaptive CD8+ T cells. One shared behavior between CD8+ T cells and NK cells is clonal expansion, where a single stimulated cell proliferates rapidly to form a diverse population of cells. For example, clones derived from single cells are most abundant during expansion when they are primarily CD27- for NK cells and CD62L- for T cells, phenotypes derived from precursor CD27+ and CD62L + cells, respectively. Here we determined the mechanistic rules involving proliferation, cell death, and differentiation of endogenous and adoptively transferred NK cells in the expansion phase of the response to MCMV infection. We found that the interplay between cell proliferation and cell death of mature CD27- NK cells and a highly proliferative CD27-Ly6C- mature subtype and intrinsic stochastic fluctuations in these processes play key roles in regulating the heterogeneity and population of the NK cell subtypes. Furthermore, we estimate rates for maturation of endogenous NK cells in homeostasis and in MCMV infection and found that only NK cell growth rates, and not differentiation rates, are appreciably increased by MCMV. Taken together, these results quantify the differences between the kinetics of NK cell antigen-specific expansion from that of CD8+T cells and unique mechanisms that give rise to the observed heterogeneity in NK cell clones generated from single NK cells in the expansion phase.

Animals↗

PubMed2026

Safety, humoral and cellular immune responses to a pre-pandemic adjuvanted influenza A (H5N8) vaccine.

Highly pathogenic avian influenza (HPAI) A(H5) viruses can be transmitted from infected birds to various mammalian species, including humans. Avian influenza viruses (AIVs), members of the Orthomyxoviridae family, possess segmented RNA genomes prone to reassortment, favoring the emergence of novel genetic traits that may alter transmissibility, pathogenicity, and antigenicity. Although no sustained human-to-human transmission has been reported, the potential adaptation of these viruses poses a significant pandemic threat. This study aimed to evaluate the non-clinical safety, toxicity, and humoral immune responses induced by an adjuvanted H5 influenza vaccine in rats and rabbits, to support future clinical safety trials in humans. Male and female Wistar rats and New Zealand rabbits were observed for 14, 28, and 90 days after receiving two intramuscular doses of the H5N8 vaccine (15 μg HA/dose) formulated with the IB160 oil-in-water emulsion adjuvant. No systemic comorbidities, central nervous system alterations, or relevant clinical signs were observed. Hematological parameters remained within normal ranges, with total and differential leukocyte counts showing only minor fluctuations (<1% of total leukocytes). Mild biochemical variations in urea and hepatic transaminase levels were not correlated with histopathological alterations. The vaccine elicited a robust humoral response soon after immunization, with all groups reaching protective HAI-antibody titers. Although antibody levels declined over time, particularly in males, they remained significantly above baseline, indicating durable immunological memory. Furthermore, the vaccine induced a specific cellular immune response, confirmed by IL-2 and TNF production by antigen-specific T lymphocytes in splenic cell cultures after the booster dose. In conclusion, the H5N8 vaccine with the IB160 adjuvant was well tolerated locally and systemically, without compromising vital organ function. The safety and immunogenicity findings are consistent with expectations for adjuvanted influenza vaccines, demonstrating strong and durable humoral and cellular immune responses.

H5N8 influenza vaccine↗

PubMed2025

Oncogenic roles of young human de novo genes and their potential as neoantigens in cancer immunotherapy.

Young human de novo genes, recently emerging from non-coding regions, are expected to contribute to human-specific traits and diseases. However, systematic explorations of this connection have been lacking. Here, we report 37 recently originated de novo genes in humans, with their evolution and characteristics defined within an updated genomic context. The expression of these genes is significantly upregulated and temporospatially expanded in tumors, partially associated with extrachromosomal DNA amplification. Depletion of 57.1% of these genes suppresses tumor cell proliferation, underscoring their roles in tumorigenesis. As a proof of concept, we developed mRNA vaccines expressing ELFN1-AS1 and TYMSOS-young genes specifically expressed during early development but reactivated exclusively in tumors. In humanized mice, these vaccines triggered specific T cell activation and inhibited tumor growth. The antigens derived from these genes are immunogenic and capable of eliciting antigen-specific T cell activation in colorectal cancer patients. These findings underscore young human de novo genes as neoantigens in cancer immunotherapy.

Humans↗

PubMed2024

Enhanced mucosal SARS-CoV-2 immunity after heterologous intramuscular mRNA prime/intranasal protein boost vaccination with a combination adjuvant.

Current COVID-19 mRNA vaccines delivered intramuscularly (IM) induce effective systemic immunity, but with suboptimal immunity at mucosal sites, limiting their ability to impart sterilizing immunity. There is strong interest in rerouting immune responses induced in the periphery by parenteral vaccination to the portal entry site of respiratory viruses, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), by mucosal vaccination. We previously demonstrated the combination adjuvant, NE/IVT, consisting of a nanoemulsion (NE) and an RNA-based RIG-I agonist (IVT) induces potent systemic and mucosal immune responses in protein-based SARS-CoV-2 vaccines administered intranasally (IN). Herein, we demonstrate priming IM with mRNA followed by heterologous IN boosting with NE/IVT adjuvanted recombinant antigen induces strong mucosal and systemic antibody responses and enhances antigen-specific T cell responses in mucosa-draining lymph nodes compared to IM/IM and IN/IN prime/boost regimens. While all regimens induced cross-neutralizing antibodies against divergent variants and sterilizing immunity in the lungs of challenged mice, mucosal vaccination, either as homologous prime/boost or heterologous IN boost after IM mRNA prime, was required to impart sterilizing immunity in the upper respiratory tract. Our data demonstrate the benefit of hybrid regimens whereby strong immune responses primed via IM vaccination are rerouted by IN vaccination to mucosal sites to provide optimal protection against SARS-CoV-2.

Animals↗

PubMed2026

TCRspec: A Recognition Interface-Informed Multimodal Method for TCR-pMHC Specificity Prediction.

Specific recognition between T-cell receptors (TCRs) and peptide-major histocompatibility complexes (pMHCs) is central to adaptive immunity, yet accurate prediction of TCR-pMHC specificity remains challenging. Existing models mainly rely on sequence features or isolated molecular structures, limiting their ability to capture interface-level determinants within the ternary recognition complex. Here, we constructed the multimodal TCR-pMHC ternary complex (MM-TCR) data set, integrating paired TCR-pMHC sequences, V/J gene annotations, and modeled TCR-pMHC complex structures refined by short molecular dynamics-based relaxation. Based on MM-TCR, we developed TCRspec, an interpretable multimodal framework combining sequence embeddings, gene-usage features, and complex-level structural representations. Under a stringent CD-HIT TCR-cluster-disjoint split, TCRspec achieved an average AUROC of 0.896 and AUPRC of 0.882 across seven antigen-specific test data sets, outperforming representative baseline models. Cross-validation and ablation analyses confirmed the contribution of ternary complex structural information and MD-refined structures. In independent OOD peptide-TCR systems, TCRspec retained discriminative performance and identified model-inferred peptide positions associated with TCR recognition, providing a structure-informed framework for TCR specificity prediction.

Receptors, Antigen, T-Cell↗

PubMed2026

A single-cell atlas of multiple myeloma defines malignant archetypes and proliferative states.

Multiple myeloma (MM) is a plasma-cell malignancy with extensive genomic and transcriptional heterogeneity, limiting disease classification and precision therapy. Here we generated a clinically annotated, population-scale, single-cell atlas of MM from 341 individuals spanning the disease and treatment continuum. We identified five recurrent malignant transcriptional archetypes and an orthogonal proliferative program associated with genomic features, therapeutic resistance and clinical outcomes. Validation in the independent CoMMpass cohort demonstrated robustness, prognostic relevance and portability across platforms. We developed a single-cell, target-discovery pipeline prioritizing malignant enrichment, cell-type specificity and tissue restriction, identifying FCRL2 as a plasma-restricted or B cell-lineage-restricted surface target expressed by malignant plasma cells. FCRL2-targeted chimeric antigen receptor T cells demonstrated antigen-specific activity in vitro and survival benefit in vivo. Together, these data provide a clinically actionable blueprint for patient stratification and precision target nomination in plasma-cell malignancies.

Multiple Myeloma↗

PubMed2026

Airway microbiome diversity, intramucosal bacteria, and spatial immunity in asthmatic adults and controls.

RATIONALE: Asthma is characterized by disruption of the thoracic airway mucosae and loss of microbial diversity. Spatial profiling of the mucosal transcriptome may systematically discover mechanisms for microbial influences on immunity. OBJECTIVES: We investigated relationships between clinical measures, microbial communities, and the host mucosal transcriptome within different strata of bronchial biopsies in subjects with and without asthma. METHODS: We performed bronchoscopy in 65 asthmatic adults and 44 healthy controls, quantifying bacterial operational taxonomic units (OTUs) in bronchial brushings by 16S ribosomal RNA (rRNA) gene amplicon sequences. Biopsy histologic features were scored blind to diagnosis. Following 16S rRNA in situ hybridization of 44 biopsies, bacterial foci were scored in epithelium, basement membrane, and stroma. Global human gene expression was quantified in epithelial and stromal compartments using digital spatial profiling. MEASUREMENTS AND MAIN RESULTS: Clinical asthma was independently predicted by basement membrane abnormalities (BaseMA), endobronchial bacterial diversity, and circulating eosinophil counts, but not by specific OTU abundances. 16S rRNA staining revealed bacteria within epithelium and mucosa of all biopsies. Intramucosal bacteria counts correlated negatively with spatially organized coexpression networks encoding antigen-specific immunity, neutrophil functions, and matrix activation, whereas BaseMA correlated positively with the adaptive immunity module. Eosinophil counts correlated with epithelial bacterial counts and senescence pathways. Clinical asthma was accompanied by upregulation of a regulatory T-cell network. CONCLUSIONS: Asthma and its related phenotypes are accompanied by complex mucosal events that extend beyond eosinophilic pathways. Components of diverse airway microbiota may modify immunity by beneficial interactions within the mucosa.

Humans↗

PubMed2004

Ex vivo phenotype and frequency of influenza virus-specific CD4 memory T cells.

Recent advances in class II tetramer staining technology have allowed reliable direct ex vivo visualization of antigen-specific CD4 T cells. In order to define the frequency and phenotype of a prototype response to a nonpersistent pathogen, we have used such techniques to analyze influenza virus-specific memory CD4 T cells directly from blood. These responses are stably detectable ex vivo at low frequencies (range, 0.00012 to 0.0061% of CD4 T cells) and display a distinct "central memory" CD62L(+) phenotype.

CD4-Positive T-Lymphocytes↗

PubMed2026

Tracking GAD-specific T-cell expansions in Type 1 diabetes by intradermal GAD-Alum challenge.

Identifying and monitoring autoreactive T cells that drive beta cell destruction remains a major obstacle to developing effective immunotherapies for type 1 diabetes (T1D). These cells are extremely rare in peripheral blood and cannot be accessed directly from the pancreas. We used intradermal injection of Glutamic Acid Decarboxylase (GAD)-Alum to recruit GAD-specific T cells to accessible sites in the skin and skin-draining lymph nodes (LNs), sampled by skin suction blisters and ultrasound-guided LN aspiration. Peripheral blood samples obtained before GAD injection were restimulated with GAD in vitro to detect reactive CD4+ T cells. Single-cell RNA sequencing (scRNAseq) followed by re-expression of selected T cell receptors (TCRs) confirmed antigen specificity. Up to 70% of T cells at the skin injection site were clonally-expanded and 4 of 14 (28%) re-expressed TCRs were GAD-reactive. In LNs 1 of 14 (4%) clonally-expanded TCRs was GAD-reactive, representing ~0.08% of all T-cells. GAD-reactive cells across compartments displayed Th1 and Th17-associated transcription signatures. These results demonstrate the intradermal autoantigen challenge and scRNAseq, enable direct identification and molecular profiling of autoreactive T cells in vivo. This minimally invasive approach provides a powerful platform for tracking antigen-specific T cells to monitor disease activity and evaluate immune interventions in T1D.

Autoimmunity↗

PubMed2026

A Multiepitope Intranasal Adenoviral Vaccine Induces Robust Mucosal Immunity and Protection against SARS‑CoV‑2.

BACKGROUND: Vaccination has been central to mitigating the COVID-19 pandemic; however, the continual emergence of SARS-CoV-2 variants of concern (VOCs) has reduced the effectiveness of current intramuscular vaccines that primarily target the Spike (S) protein. Although updated formulations are periodically introduced, there remains a critical need for next-generation vaccine platforms capable of inducing broad, variant-independent protection. Here we evaluate a heterologous intranasal (i.n.) prime-boost vaccination strategy using bovine adenoviral (BAd) and chimpanzee adenoviral (ChAd) vectors expressing the S1 subunit in combination with either full-length membrane (M) and nucleocapsid (N) proteins (Ad-S1 + N + M) or multiepitope constructs derived from M and N (Ad-S1 + Epi/N + Epi/M). The constructs were incorporated with the autophagy-inducing peptide C5 (AIP-C5) to enhance antigen-specific T-cell responses. RESULTS: In BALB/c mice, Ad-S1 + Epi/N + Epi/M vaccination induced robust S1-specific immunity while simultaneously inducing strong N- and M-specific humoral and cellular responses that were comparable to or greater than those induced by Ad-S1 + N + M. All S1-containing formulations generated high neutralizing antibody titers (~ 3.8 log₁₀) against Omicron B.1.1.529 and BA.2.86 variants, although titers against the ancestral Wuhan strain were approximately one log₁₀ lower. In K18-hACE2 mice, i.n. immunization with S1-expressing vectors provided near-complete protection against BA.2.86 challenge, with undetectable lung viral titers and viral genome copies. CONCLUSION: An i.n. multiepitope adenoviral vaccine incorporating conserved SARS-CoV-2 antigens induces robust mucosal, humoral, and cellular immune responses and confers significant protection following SARS-CoV-2 challenge.

Animals↗