Oncolytic viruses (OVs) encoding a variety of transgenes have been evaluated as therapeutic tools to increase the efficacy of chimeric antigen receptor (CAR)–modified T cells in the solid tumor microenvironment (TME). Here, using systemically delivered OVs and CAR T cells in immunocompetent mouse models, we have defined a mechanism by which OVs can potentiate CAR T cell efficacy against solid tumor models of melanoma and glioma. We show that stimulation of the native T cell receptor (TCR) with viral or virally encoded epitopes gives rise to enhanced proliferation, CAR-directed antitumor function, and distinct memory phenotypes. In vivo expansion of dual-specific (DS) CAR T cells was leveraged by in vitro preloading with oncolytic vesicular stomatitis virus (VSV) or reovirus, allowing for a further in vivo expansion and reactivation of T cells by homologous boosting. This treatment led to prolonged survival of mice with subcutaneous melanoma and intracranial glioma tumors. Human CD19 CAR T cells could also be expanded in vitro with TCR reactivity against viral or virally encoded antigens and was associated with greater CAR-directed cytokine production. Our data highlight the utility of combining OV and CAR T cell therapy and show that stimulation of the native TCR can be exploited to enhance CAR T cell activity and efficacy in mice.

Metabolic dysfunction–associated steatohepatitis (MASH) is a progressive liver disease characterized by complex interactions between lipotoxicity, ER stress responses, and immune-mediated inflammation. We identified enrichment of the proinflammatory alarmin S100 calcium-binding protein A11 (S100A11) on extracellular vesicles stimulated by palmitate-induced lipotoxic ER stress with concomitant upregulation of hepatocellular S100A11 abundance in an IRE1A-XBP1s–dependent manner. We next investigated the epigenetic mechanisms that regulate this stress response. Publicly available human liver ChIP-Seq GEO datasets demonstrated a region of histone H3 lysine 27 (H3K27) acetylation upstream of the S100A11 promoter. H3K27 acetylation ChIP-qPCR demonstrated a positive correlation between lipotoxic ER stress and H3K27 acetylation of the region, which we termed the lipotoxicity-influenced enhancer (LIE) domain. CRISPR-mediated repression of the LIE domain reduced palmitate-induced H3K27 acetylation and corresponding S100A11 upregulation in Huh7 cells and immortalized mouse hepatocytes. Silencing of the murine LIE in 2 independent steatohepatitis models demonstrated reduced S100a11 upregulation and attenuated liver injury. We confirmed H3K27 acetylation and XBP1s occupancy at the LIE domain in human MASH liver samples and an increase in hepatocyte-derived S100A11-enriched extracellular vesicles in MASH patient plasma. Our studies demonstrate a LIE domain that mediates hepatic S100A11 upregulation. This pathway may be a potential therapeutic target in MASH.

Background: Long-lived, re-activatable immunity to SARS-CoV-2 and its emerging variants will rely on T cells recognizing conserved regions of viral proteins across strains. Heterologous prime–boost regimens can elicit elevated levels of circulating CD8+ T cells that provide a reservoir of first responders upon viral infection. Although most vaccines are currently delivered intramuscularly (IM), the initial site of infection is the nasal cavity. Methods: Here, we tested the hypothesis that a heterologous prime and boost vaccine regimen delivered intranasally (IN) will generate improved immune responses locally at the site of virus infection compared to intramuscular vaccine/booster regimens. Results: In a transgenic human ACE2 murine model, both a Spike-expressing single-cycle adenovirus (SC-Ad) and an IFNß safety-enhanced replication-competent Vesicular Stomatitis Virus (VSV) platform generated anti-Spike antibody and T-cell responses that diminished with age. Although SC-Ad-Spike boosted a prime with VSV-Spike-mIFNß, SC-Ad-Spike alone induced maximal levels of IgG, IgA, and CD8+ T-cell responses. Conclusions: There were significant differences in T-cell responses in spleens compared to lungs, and the intranasal boost was significantly superior to the intramuscular boost in generating sentinel immune effectors at the site of the virus encounter in the lungs. These data show that serious consideration should be given to intranasal boosting with anti-SARS-CoV-2 vaccines.

Chimeric antigen receptor (CAR) T cell therapy faces many challenges against solid tumors including T cell exhaustion and poor CAR durability. Here, we show that engaging the CAR T cell endogenous T cell receptor (TCR) using an oncolytic virus enhances CAR T cell functionality, durability, and therapy. Upon combination therapy of solid tumors with CAR T cells and vesicular stomatitis virus (VSV), a subpopulation of antiviral, TCR-primed CAR T cells was generated with enhanced effector functions, altered activation states, and differential gene and protein expression when compared to non–TCR-primed CAR T cells. Single-cell RNA sequencing showed clonal expansion of anti-VSV CAR T cells and enhancement of effector-associated genes with VSV-mediated CAR T cell expansion. CD4 T cells played a pivotal role in the development of these TCR-primed CAR T cells. These results provide a strong rationale both for a novel use of systemic oncolytic virotherapy and for directly exploiting the CAR T cell TCR to fine tune the CAR T cell phenotype and function.

T-cell immune tolerance is established in part through the activity of the autoimmune regulator (AIRE) transcription factor in medullary thymic epithelial cells (mTEC) of the thymus. AIRE induces expression of peripheral tissue–specific self-antigens for presentation to naïve T cells to promote activation/deletion of autoreactive T cells. This traditional role of AIRE in mTECs is to prevent autoimmunity. Herein, we demonstrate that tumors mimic the role of AIRE in mTECs to evade immune rejection. We found that AIRE induced a profile of “selfness” at the RNA and protein levels which, when presented on major histocompatibility complexes (MHC), shielded the tumor from inherently self-tolerized T cells. Moreover, we describe an in vivo immunotherapy in which engineered changes in AIRE expression in tumor cells altered their profile of selfness, exposing both AIRE-modified and parental unmodified tumor cells to T-cell attack. Therefore, by resetting the immunologic selfness of cancer cells, this AIRE-mediated immunotherapy (i) converted a highly tolerized T-cell compartment into a tumor-reactive T-cell population; (ii) conferred upon nonimmunogenic tumors de novo sensitivity to immune checkpoint blockade; (iii) removed the need to identify potentially immunogenic tumor-associated antigens as targets for generation of T-cell responses; and (iv) lead to potent T cell–mediated rejection of aggressive, immunologically cold, nonimmunogenic tumors. Patient RNA sequencing data showed that the expression of AIRE predicted response to immune therapies with a strong correlation between AIRE expression and markers of T-cell receptor signaling, suggesting that our studies have therapeutic translational value.

Table S4 from Cancer Immunotherapy Using AIRE Conditioning of the Tumor Epitopeome