Jul 2026· Journal of Immunology· Vol 215· 0 citations
Abstract
Targeted immunotherapies aimed at enhancing antiviral T cell responses are of particular interest for treating neurotropic viral infections such as West Nile Virus (WNV), which lacks a licensed human vaccine. Previous studies have shown that DEC-205+ dendritic cells (DCs) in the central nervous system (CNS) play a role in reactivating antiviral immunity during WNV infection.
Methods to investigate this: a hybrid scFv antibody targeting DEC-205 and conjugated to a peptide from the WNV NS4b protein was administered to mice infected with WNV-TX. Poly I:C was co-delivered as an adjuvant to promote DC maturation. Immunological outcomes were assessed by quantifying co-stimulatory molecule expression (CD40, CD80, CD86) on DCs and evaluating T cell activation markers and cytokine profiles.
Mice receiving the DEC-205—NS4b scFv showed increased expression of activation markers and higher levels of pro-inflammatory cytokines, suggesting enhanced antiviral immunity.
These findings support targeted DC-based strategies as a promising approach for future WNV vaccine development.
Cal Poly Pomona Project Hatchery
Immune Response Regulation: Cellular Mechanisms (IRC)
Subunit vaccines are safe but rarely induce robust, long-lasting immunity, especially cell-mediated immunity (CMI). Here, we investigated the potential of IVAX-1, a combination of TLR4 (MPLA) and TLR9 (CpG 1018) agonists formulated in a squalene oil-in-water emulsion (AddaVax), to mediate protection and generate CMI.
We leveraged a murine H5N1 influenza model with fate-map reporters, conditional knock-out mice, multiphoton imaging, and flow cytometry to elucidate early spatiotemporal features of IVAX-1-driven immunity. Antigen-specific CMI was evaluated via ELISpot and recall assays.
Immune priming with IVAX-1 enhanced dendritic cell (DC) maturation and recruitment of myeloid cells to the injection site, resulting in higher numbers of neutrophils, monocytes, and antigen-presenting DCs in the draining lymph node (DLN), independent of antigen clearance kinetics. This induced islands of IFN-γ+ cells in the DLN, suggesting clonal expansion. In addition, IVAX-1 generated a robust antigen-specific functional (IFN-γ+) T cell response. Deletion of Type 1 conventional DCs (XCR1+) cells abrogated IVAX-1-mediated T cell response. Furthermore, immunization with IVAX-1 generated significantly higher numbers of flu-specific memory T cells in the lungs and spleen. IVAX-1 conferred durable protection and superior viral clearance from the lungs up to 60 days after immunization.
By leveraging synergistic innate immune activation through multiple TLR pathways, the combination optimizes T cell priming without relying on antigen depot effects. Our findings identify key early innate immune events and cellular mediators that drive robust CMI and demonstrate the potential of TLR agonist combinations to elicit durable T-cell immunity.
NIH/NIAID grants U01AI160397 & R01AI168063; Adjuvant Comparison and Characterization contract BAA-DAIT-75N93020R00022; and grant from the Defense Threat Reduction Agency #HDTRA-18-1-0036; UC Irvine UROP Research Experience Fellowship; NIH-MARC U-STAR trai
Vaccines and Immunotherapy (VAC)
Dan Nguyen, D. Davies, J. Felgner et al.· Journal of Immunology· 0 citations
Cross-presentation (XPT) is pivotal for inducing antigen (Ag)-specific CD8+ T cell responses, which is linked to better therapeutic outcomes. However, in the context of therapeutic vaccination, how to promote T cell cross-priming in vivo remains unclear. This motivates elucidating the mechanisms underlying XPT by specific cross-presenting subsets under physiological conditions.
Ag-specific cytotoxic responses in EG7-OVA tumor model upon adjuvanted vaccination with Th1-stimulating adjuvant was assessed for the mechanism underlying cross-priming. The key cross-presenting subsets under adjuvanted vaccination were analyzed by flow cytometry. The potential pathways related to induced XPT were discovered by RNA sequencing (RNA-seq) and pathway analysis and the results were validated by immunoblotting and OT-I XPT assay. Unbiased single-cell RNA-seq was employed to define the counterpart in human immune system (HIS) mice.
Adjuvanted vaccination elicited a robust Ag-specific anti-tumor response and expanded inflammatory cDC2 (inf-cDC2) in tumor model. In knockout mice studies, inf-cDC2 emerges as the dominant cross-presenting subset during vaccination. RNA-seq analysis highlighted autophagy-related pathways, next confirming that autophagy inhibition drives XPT. Mechanistically, impeding the fusion of autophagosomes and lysosomes in DCs could prime T cells by prolonged XPT. In HIS mice, DC3 was identified as the phenotypic counterpart of inf-cDC2 under vaccination. Adjuvant-induced pathways were highly enriched in autophagy and autophagy inhibition exclusively within DC3 promotes XPT.
We identified murine inf-cDC2 and human DC3–not cDC1–are the key player in XPT in the context of adjuvanted vaccination and this marked function strongly depends on autophagy blockade. Prioritizing autophagy inhibition, particularly in these DCs, could effectively augment Ag-specific anti-tumor immunity. This bridges the gap between preclinical and clinical investigations in cancer vaccinology.
n/a
Classical and Non-Classical Antigen Presenting Cells (APC)
Yu-Chi Huang, Pei-Chuan Chiang, C. Tsai et al.· Journal of Immunology· 0 citations
Dengue virus (DENV) nonstructural protein 3 (NS3) is essential for viral replication and host immune evasion. While its protease domain (NS3pro) has been linked to T-cell anergy, its role in inducing regulatory T cells (Tregs) requires further exploration. To analyze the induction of diverse regulatory T-cell populations in BALB/c mice immunized with recombinant rNS3pro proteins from the four DENV serotypes. Mice were immunized with rNS3pro, and splenocytes were stimulated in vitro with homologous proteins. Cytokine expression and T-cell phenotypes-including markers for activation, exhaustion, and cytotoxicity-were analyzed via RT-PCR, ELISA, and flow cytometry. rNS3pro immunization induced a predominantly regulatory-associated response characterized by significant IL-10 expression. A marked expansion of CD4+CD25+ T cells (23.5% vs. 1.05% in controls) was observed, encompassing CD25+FoxP3+ regulatory-like T cells, alongside FoxP3-independent subsets expressing CD25+IL-10+ and CD25+TGF-β+. These cells co-expressed cytotoxicity-associated (FoxP3+Perforin+/GzB+) and co-inhibitory (CTLA-4+, PD-1+) markers. Effector CD8+ T-cell proliferation was significantly inhibited and could not be restored by exogenous IL-2. In conclusion, DENV rNS3pro immunization drives a robust expansion of multifaceted regulatory-like T-cell phenotypes. This immunomodulatory response correlates with compromised CD8+ effector proliferation, identifying the NS3 protease domain as a potential player in DENV immune evasion strategies.
V. Romero-Cruz, Á. Ramos-Ligonio, Diana Lizzet Murrieta-León et al.· Acta Tropica· 0 citations
Influenza A virus (IAV) remains a global health challenge, and current intramuscular vaccines often fail to induce strong mucosal immunity in the airways. We have developed a novel intranasal vaccination strategy in mice using a Protease-Activated Receptor 2 (PAR-2)-activating peptide (AP) as an adjuvant co-delivered with influenza virosomes. We have previously shown that this peptide enhances virosome-induced CD8+ T cell responses and protection against lethal IAV challenge. Here we studied the immune changes induced by this peptide in draining lymph nodes and the lung. We show that AP promotes accumulation of lymphoid and myeloid cells to the mediastinal lymph nodes, including CD3+ T cells and CD11b-/CD11b+ dendritic cells (DCs), and enhances DC maturation and CCR7 expression, which facilitates migration to lymph nodes. Along with accumulation of antigen-presenting cells, we detected increases in naïve, central memory (TCM), and effector memory (TEM) T cells. In addition, AP promoted the presence of tissue-resident memory T cells (TRM) and monocytes in the lungs, supporting rapid tissue-targeted immunity. These results demonstrate that AP functions as a potent mucosal adjuvant by enhancing early immune cell recruitment, DC activation, and adaptive T cell responses in lymph nodes, ultimately promoting tissue-resident immunity. Our findings highlight the potential of PAR-2 activation to improve efficacy of mucosal influenza vaccines.
C. Kornuta, Gang Zhou, K. Kane et al.· Vaccine· 0 citations
Investigating how the vaccine shapes the CD4+ T cell immunity and how these responses cooperate in reducing the acquisition found that DV1 DNA/ALVAC/gp120 vaccine elicited envelope-specific immunomodulatory Tr1 CD4+ T cells, and that total Tr1 responses were associated with a reduced risk of viral acquisition.
Massimiliano Bissa, S. Fourati, Sohyoung Kim et al.· Journal of Immunology· 0 citations
The modification of RNA by the incorporation of N-methyl pseudo-uridine (N1mψ) renders the mRNA less inflammatory, resulting in durable cellular and humoral responses. Interestingly, mRNA-LNP vaccines still elicit strong innate immune activation and stimulate the production of type I interferons (IFN-I) by antigen-presenting cells (APCs). IFN-I is critical in the induction of CD8 T-cell responses to mRNA vaccines; however, the mechanisms underlying this process are poorly understood.
We determined protection from lethal infection with ectromelia virus in mice with cell-specific deletion of IFNAR1, as well as in mice deficient in specific IFN-I, following vaccination with a previously described EVM158 mRNA-LNP vaccine containing an immunodominant CD8 T-cell epitope.
We demonstrate that the optimal induction of CD8 T-cells requires IFN-I signaling in multiple myeloid cell types, not just in CD8 T-cells, dendritic cells, or monocytes. We also show that at optimal vaccine doses, IFN-β- and IFN-α-deficient mice generate protective CD8 T-cell responses. However, at suboptimal doses, male mice deficient in IFN-β and in IFN-α4, which are regulated by constitutive transcription factors, do not generate completely protective CD8 T cells. Moreover, mice deficient in the NF-κB binding site in the IFN-β promoter and the transcription factor IRF7 generate poorly protective responses.
Our results indicate that optimal induction of protective CD8 T-cell responses by mRNA LNP vaccines requires IFN-I signaling in myeloid cells but not in CD8 T-cells, that IFN-β and IFN-α can individually provide the signals required for protection, and that regulation of IFN-β by NF-κB and all IFN-I subtypes by IRF is required to induce protective CD8 T-cells.
NIAID, NIH
Vaccines and Immunotherapy (VAC)
Samit Kafle, Brian Montoya, Carolina R. Melo-Silva et al.· Journal of Immunology· 0 citations
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