Explore the vast range of titles available.

Cellular metabolism underpins immune cell functionality, yet our understanding of metabolic influences in human dendritic cell biology and their ability to orchestrate immune responses is poorly developed. Here, we map single-cell metabolic states and immune profiles of inflammatory and tolerogenic monocytic dendritic cells using recently developed multiparametric approaches. Single-cell metabolic pathway activation scores reveal simultaneous engagement of multiple metabolic pathways in distinct monocytic dendritic cell differentiation stages. GM-CSF/IL4-induce rapid reprogramming of glycolytic monocytes and transient co-activation of mitochondrial pathways followed by TLR4-dependent maturation of dendritic cells. Skewing of the mTOR:AMPK phosphorylation balance and upregulation of OXPHOS, glycolytic and fatty acid oxidation metabolism underpin metabolic hyperactivity and an immunosuppressive phenotype of tolerogenic dendritic cells, which exhibit maturation-resistance and a de-differentiated immune phenotype marked by unique immunoregulatory receptor signatures. This single-cell dataset provides important insights into metabolic pathways impacting the immune profiles of human dendritic cells. Assessing metabolic activity within single cells rather than at a population level has a number of advantages. Here, the authors use a flow and mass cytometry based approach that assess the metabolic differences between populations of human immune stimulatory and tolerogenic dendritic cells.

Efficacy of cancer vaccines remains low and mechanistic understanding of antigen presenting cell function in cancer may improve vaccine design and outcomes. Here, we analyze the transcriptomic and immune-metabolic profiles of Dendritic Cells (DCs) from 35 subjects enrolled in a trial of DC vaccines in late-stage melanoma (NCT01622933). Multiple platforms identify metabolism as an important biomarker of DC function and patient overall survival (OS). We demonstrate multiple immune and metabolic gene expression pathway alterations, a functional decrease in OCR/OXPHOS and increase in ECAR/glycolysis in patient vaccines. To dissect molecular mechanisms, we utilize single cell SCENITH functional profiling and show patient clinical outcomes (OS) correlate with DC metabolic profile, and that metabolism is linked to immune phenotype. With single cell metabolic regulome profiling, we show that MCT1 (monocarboxylate transporter-1), a lactate transporter, is increased in patient DCs, as is glucose uptake and lactate secretion. Importantly, pre-vaccination circulating myeloid cells in patients used as precursors for DC vaccine generation are significantly skewed metabolically as are several DC subsets. Together, we demonstrate that the metabolic profile of DC is tightly associated with the immunostimulatory potential of DC vaccines from cancer patients. We link phenotypic and functional metabolic changes to immune signatures that correspond to suppressed DC differentiation. Efficacy of dendritic cell (DC)-based vaccines remains unsatisfactory. Here the authors analyse the transcriptomic and immune-metabolic profiles of DCs from patients enrolled in a DC vaccine trial in late-stage melanoma, suggesting that the metabolic profile of DC is associated with the immunostimulatory potential of the cancer vaccine.

Self-amplifying RNA (saRNA)-based vaccines have emerged as a potent and durable RNA vaccine platform relative to first generation mRNA vaccines. However, RNA vaccine platforms trigger undesirable side effects at protective doses, underscoring the need for improved tolerability. To address this, we leveraged the Cardiovirus leader protein, which is well-characterized to dampen host innate signaling by modulating nucleocytoplasmic transport (NCT). Co-administration of a leader-protein-encoding mRNA (which we have named “RNAx”) delivered alongside vaccine cargo saRNA reduced interferon production while enhancing Influenza hemagglutinin (HA) expression in human primary cells and murine models. RNAx potently decreased serum biomarkers of reactogenicity after immunizations with an HA-expressing saRNA-LNP vaccine while maintaining the magnitude of the antibody and cellular response. RNAx also consistently enhanced binding antibody titers after a single injection and in some conditions enhanced binding antibody and neutralization titers post-boost. These findings support RNAx as a promising platform approach for improving tolerability of saRNA-LNP vaccines while preserving or enhancing immunogenicity.

Selection of a pre-clinical non-human primate (NHP) model is essential when evaluating therapeutic vaccine and treatment strategies for HIV. SIV and SHIV-infected NHPs exhibit a range of viral burdens, pathologies, and responses to combinatorial antiretroviral therapy (cART) regimens and the choice of the NHP model for AIDS could influence outcomes in studies investigating interventions. Previously, in rhesus macaques (RMs) we showed that maintenance of mucosal Th17/Treg homeostasis during SIV infection correlated with a better virological response to cART. Here, in RMs we compared viral kinetics and dysregulation of gut homeostasis, defined by T cell subset disruption, during highly pathogenic SIVΔB670 compared to SHIV-1157ipd3N4 infection. SHIV infection resulted in lower acute viremia and less disruption to gut CD4 T-cell homeostasis. Additionally, 24/24 SHIV-infected versus 10/19 SIV-infected animals had sustained viral suppression <100 copies/mL of plasma after 5 months of cART. Significantly, the more profound viral suppression during cART in a subset of SIV and all SHIV-infected RMs corresponded with less gut immune dysregulation during acute SIV/SHIV infection, defined by maintenance of the Th17/Treg ratio. These results highlight significant differences in viral control during cART and gut dysregulation in NHP AIDS models and suggest that selection of a model may impact the evaluation of candidate therapeutic interventions for HIV treatment and cure strategies.

To accelerate the development of T cell–based immunotherapies that are effective for more patients with cancer, there is an urgent need to decipher the precise attributes of the ideal therapeutic T cell. In March 2021, the Parker Institute of Cancer Immunotherapy and 10x Genomics partnered to bring together a group of T cell immunotherapy researchers and single-cell-technology innovators for a day’s workshop. Participants evaluated the current cutting edge of knowledge, identified areas for focused technology development, and put forward a call to action to the field. Insights were provided on how to best leverage single-cell technologies and key areas for future development were proposed — with the goal of facilitating a better understanding of T cell research and translation of this research into effective cancer immunotherapies. The key points of discussion that emerged from this workshop are summarized here.

Efficacy of cancer vaccines remains low and mechanistic understanding of antigen presenting cell function in cancer may improve vaccine design and outcomes. Here, we analyze the transcriptomic and immune-metabolic profiles of Dendritic Cells (DCs) from 35 subjects enrolled in a trial of DC vaccines in late-stage melanoma (NCT01622933). Multiple platforms identify metabolism as an important biomarker of DC function and patient overall survival (OS). We demonstrate multiple immune and metabolic gene expression pathway alterations, a functional decrease in OCR/OXPHOS and increase in ECAR/glycolysis in patient vaccines. To dissect molecular mechanisms, we utilize single cell SCENITH functional profiling and show patient clinical outcomes (OS) correlate with DC metabolic profile, and that metabolism is linked to immune phenotype. With single cell metabolic regulome profiling, we show that MCT1 (monocarboxylate transporter-1), a lactate transporter, is increased in patient DCs, as is glucose uptake and lactate secretion. Importantly, pre-vaccination circulating myeloid cells in patients used as precursors for DC vaccine generation are significantly skewed metabolically as are several DC subsets. Together, we demonstrate that the metabolic profile of DC is tightly associated with the immunostimulatory potential of DC vaccines from cancer patients. We link phenotypic and functional metabolic changes to immune signatures that correspond to suppressed DC differentiation.

Abstract A therapeutic vaccine that induces lasting control of HIV infection has the potential to eliminate the need for lifelong adherence to antiretroviral therapy (ART). This study investigated the efficacy of a therapeutic DNA vaccine delivered with a novel combination of adjuvants and immunomodulators to augment T cell immunity in the blood and gut-associated lymphoid tissue. In SIV-infected rhesus macaques, a DNA vaccine delivered by intradermal electroporation and expressing SIV Env, Gag, and Pol, and a combination of adjuvant plasmids expressing the catalytic A1 subunit of E. coli heat labile enterotoxin (LTA1), IL-12, IL-33, retinaldehyde dehydrogenase 2 and the immunomodulators soluble PD-1 and soluble CD80, significantly enhanced the breadth and magnitude of Gag-specific IFN-γ T cell responses when compared to controls that were mock vaccinated or received the same DNA vaccine delivered by Gene Gun with a single adjuvant, the E. coli heat labile enterotoxin, LT. Notably, the DNA vaccine and adjuvant combination protected 3/5 animals from viral rebound, compared to only 1/4 mock vaccinated animals and 1/5 animals that received the DNA vaccine and LT. The lower viral burden among controllers during analytical treatment interruption significantly correlated with higher polyfunctional CD8+ T-cells (CD8+ T cells expressing 3 or more effector functions) in both mesenteric lymph nodes and blood measured during ART and analytical treatment interruption. Interestingly, controllers also had lower viral loads during acute infection and ART suggesting that inherent host-viral interactions induced prior to ART initiation likely influenced the response to therapeutic vaccination. These data indicate that gut mucosal immune responses combined with effective ART may play a key role in containing residual virus post-ART and highlight the need for therapeutic vaccines and adjuvants that can restore functional quality of peripheral and mucosal T cell responses before and during ART. Author Summary HIV has caused significant human disease and mortality since its emergence in the 1980s. Furthermore, although antiretroviral therapy (ART) effectively reduces viral replication, stopping ART leads to increased viral loads and disease progression in most HIV-infected people. A therapeutic vaccine could enable HIV-infected people to control their infection without ART, but none of the vaccines that were tested in clinical trials so far have induced long-lasting control of virus replication. Here, we used the SIV rhesus macaque model to test a therapeutic vaccine consisting of DNA expressing SIV proteins and a novel combination of adjuvants to boost virus-specific immune responses. We found that our vaccine strategy significantly enhanced SIV-specific T cell responses when compared to controls and protected 3/5 animals from viral rebound. We determined that lower levels of virus replication post-ART were associated with enhanced T cell immunity in the gut-draining lymph nodes and blood. Our study highlights the critical role of T cell immunity for control of SIV and HIV replication and demonstrates that a successful therapeutic vaccine for HIV will need to elicit potent T cell responses in both the blood and gut-associated tissues.

Self-amplifying RNA (saRNA)-based vaccines have emerged as a potent and durable RNA vaccine platform. However, RNA vaccine platforms trigger undesirable side effects at protective doses, underscoring the need for improved tolerability. To address this, we leveraged the Cardiovirus leader protein, which is well-characterized to dampen host innate signaling by modulating nucleocytoplasmic transport (NCT). Co-administration of a leader-protein-encoding mRNA (which we have named “RNAx”) delivered alongside vaccine cargo saRNA reduced interferon production while enhancing Influenza hemagglutinin (HA) expression in human primary cells and murine models. RNAx potently decreased serum biomarkers of reactogenicity after immunizations with an HA-expressing saRNA-LNP vaccine while maintaining the magnitude of the antibody and cellular response. RNAx also consistently enhanced binding antibody titers after a single injection and in some conditions enhanced binding antibody and neutralization titers post-boost. These findings support RNAx as a promising platform approach for improving tolerability of saRNA-LNP vaccines while preserving or enhancing immunogenicity.