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Five seismoacoustic research arrays and one infrasound research array located across the southern Korean peninsula have been installed, maintained, and are cooperatively operated by Southern Methodist University and Korea Institute of Geoscience and Mineral Resources. The seismoacousitc arrays are each composed of 1–5 broadband seismometers spaced from 0.5 to 1.5 km and 4–16 infrasound sensors spaced from 0.1 to 1.5 km. The arrays—BRDAR, CHNAR, KSGAR, KMPAR, TJIAR, and YPDAR—have recorded regional seismic and infrasound signals from the six underground nuclear explosions conducted by Democratic People’s Republic of Korea. These seismoacoustic data are being made available for researchers interested in studying and quantifying the explosion source functions of these events as well as wave propagation effects in the solid earth and atmosphere as constrained by seismic and infrasound observations at regional distances.

In bystander activation, pre-existing memory CD8+ T cells unrelated to the infecting microbes are activated by cytokines without cognate Ags. The detailed mechanisms and unique gene signature of bystander activation remain to be elucidated. In this study, we investigated bystander activation of OT-1 memory cells in a mouse model of influenza infection. We found that OT-1 memory cells are activated with upregulation of granzyme B and IFN-γ, during PR8 (A/Puerto Rico/8/1934) infection, and IL-15 is a critical cytokine for bystander activation. In transcriptomic analysis, the IFN-induced gene signature was upregulated in bystander-activated OT-1 memory cells during PR8 infection but not in the presence of TCR stimulation. Among the IFN-induced genes, upregulation of IFN-induced transmembrane protein 3 (IFITM3) distinguished bystander-activated OT-1 memory cells from TCR-activated OT-1 memory cells. Therefore, we reveal that bystander-activated memory CD8+ T cells have a unique transcriptomic feature compared with TCR-activated memory CD8+ T cells. In particular, IFITM3 upregulation can be used as a marker of bystander-activated memory CD8+ T cells at early infection.

Following the development of unconventional oil and gas production in the Fort Worth Basin, Texas, a rapid increase in basin-wide seismicity began in 2008 that grew to include earthquakes affecting a substantial portion of the Dallas–Fort Worth metropolitan area. To assess and mitigate the seismic hazard, which in this region is impacted by the thickness of the sedimentary basin and accompanying soft soil layer, we estimate site effects at 22 seismic stations deployed to record these earthquakes. Site responses are derived using two different datasets and approaches: (1) a modified generalized inversion technique (GIT) based on the S-wave Fourier amplitude spectra from earthquakes; and (2) application of the quarter-wavelength approximation (QWA) using estimates of average shear-wave velocities in the upper 30 m, known as VS30. We find that site amplification estimates based on the two techniques are roughly consistent with one another (median of the amplification ratio = 0.92) over frequencies where a quarter-wavelength corresponds to ∼30 m depth. The site amplification factors from the two approaches are found on average to be about 3 at the quarter-wavelength frequency (QWF). These site amplification estimates are not well correlated with geologic characteristics including rock type and geologic age. Finally, QWA values at six sites do not match GIT site amplification at the QWF (outside of ± median absolute deviations boundary), which we attribute to a combination of the underlying assumptions of the QWA, uncertainty in VS30 estimates, and unmodeled site response complexity.

BackgroundTumour-unrelated, virus-specific bystander CD8+T cells were recently shown to be abundant among tumour-infiltrating lymphocytes (TILs). However, their roles in tumour immunity have not been elucidated yet.MethodsWe studied the characteristics of bystander CD8+TILs from non-small cell lung cancer (NSCLC) tissues (N=66) and their activation by interleukin (IL)-15 to repurpose them for tumour immunotherapy.ResultsWe show that bystander CD8+TILs specific to various viruses are present in human NSCLC tissues. We stimulated CD8+TILs ex vivo using IL-15 without cognate antigens and found that IL-15 treatment upregulated NKG2D expression on CD8+TILs, resulting in NKG2D-dependent production of interferon (IFN)-γ (p=0.0006). Finally, we tested whether IL-15 treatment can control tumour growth in a murine NSCLC model with or without a history of murine cytomegalovirus (MCMV) infection. IL-15 treatment reduced the number of tumour nodules in the lung only in mice with MCMV infection (p=0.0037). We confirmed that MCMV-specific bystander CD8+TILs produced interferon (IFN)-γ after IL-15 treatment, and that IL-15 treatment in MCMV-infected mice upregulated tumour necrosis factor-α and IFN-γ responsive genes in tumour microenvironment.ConclusionThus, the study demonstrates that bystander CD8+TILs can be repurposed by IL-15 for tumour immunotherapy.

BACKGROUND The heterogeneous immune landscapes of intrahepatic cholangiocarcinoma (ICC) remain largely unknown. Here we aimed to investigate the implications of tissue-resident memory (TRM)-related features of tumour-infiltrating CD8+ T cells (CD8+ TILs) from ICC patients. METHODS From ICC patients, we obtained blood samples and ICC surgical specimens (n = 33). We performed multicolour flow cytometry, multiplexed immunohistochemistry and RNA sequencing. RESULTS When compared to peripheral CD8+ T cells, the CD8+ TILs included significantly higher proportions of the CD69+ CD103- and CD69+ CD103+ TRM-like subsets (P

Exhausted T cells in the tumor microenvironment are major targets of immunotherapies. However, the exhaustion status of CD8+ tumor-infiltrating lymphocytes (TILs) in bladder cancer has not been comprehensively evaluated. Herein, we examined distinct exhaustion status of CD8+ TILs based on the level of programmed cell death-1 (PD-1) and thymocyte selection-associated high mobility group box protein (TOX) expression in urothelial bladder cancer. We also evaluated the reinvigoration of exhausted CD8+ TILs upon ex vivo treatment with inhibitory checkpoint blockers. TOX-expressing PD-1highCD8+ TILs had the highest expression of immune checkpoint receptors (ICRs), the most terminally exhausted features, and the highest tumor antigen reactivity among PD-1+CD8+ TILs. Bladder cancer patients with a high percentage of PD-1highTOX+CD8+ TILs had more progressed T-cell exhaustion features and higher programmed death-ligand 1 expression in tumor tissues. TIGIT was the most frequent co-expressed ICR on PD-1+CD8+ TILs, and TIGIT blockade enhanced the PD-1 blockade-mediated cytokine production by CD8+ TILs from bladder cancer patients. Our findings provide an improved understanding of the heterogeneous exhaustion status of CD8+ TILs and additional immunotherapy strategies to improve outcomes of bladder cancer patients.

Kirsten rat sarcoma viral oncogene (KRAS) mutations are present in 26% of non-small cell lung cancer (NSCLC) patients (The Cancer Genome Atlas data). Studies have reported the presence of spatial or intra-tumoral heterogeneity of KRAS mutations. Though resistance to mutant KRAS inhibitors targeting a specific form of major KRAS mutations (e.g, G12C or G12D) is multifaceted, intra-tumoral heterogeneity of KRAS mutation is one of the crucial factors for the intrinsic resistance to the inhibitor. Multi-targeting of different KRAS mutations can prevent resistance due to the heterogeneity of KRAS mutations within a tumor. To achieve this, we incorporated an mRNA-based cancer vaccine containing transcripts for multiple KRAS mutant antigens. Our KRAS cancer vaccine (CV) candidate showed significantly attenuated tumor growth by 37% in the syngeneic KRAS G12C-expressing LL/2 tumor-bearing mice. CV treatment group showed significantly decreased tumor size by 45.4% after biopsy. Moreover, the mice treated with KRAS CV showed spleen enlarged by 42.6% indicating increased immune responses. To confirm, the expansion of T cells in the cancer vaccine-treated group, we collected tumor tissues and analyzed proportions of CD4+ and CD8+ T lymphocytes in the tumor. We found a 14.5-fold increase in infiltration of CD8+ T cells and a 0.5-fold increase in CD8+ CD44+ memory/effector T cells in the tumors from mice treated with KRAS CV. Whereas CD4+ Foxp3+ Treg cells were decreased by 3.9-fold in the tumor. HLA-A*02 is the most common MHC class I allele. To investigate the changes in MHC expression, we conducted FACS analysis using HLA-A*02 antibodies after ex vivo treatment of KRAS CV on the human peripheral blood mononuclear cells (hPBMCs). KRAS CV treatment facilitated higher proportions of HLA-A*02+ monocytes (CD14+) and B cells (CD19+). Though LL/2 tumor model has been considered an immunosuppressive model, our results suggest that the KRAS CV can significantly enhance immune responses, thereby suppressing tumor growth. Citation Format: Seung-Hyun Shin, Youngjin Han, Chang Gyu Lim, Yong Ho Heo, Seongju Jeong, Yu-Yon Kim, In Young Choi. An mRNA-based cancer vaccine multi-targeting KRAS mutations inhibits tumor growth by increasing immune response in KRAS mutant LL/2 mouse model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 2 (Clinical Trials and Late-Breaking Research); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(8_Suppl):Abstract nr LB222.

Although recombinant IL-2 (aldesleukin) was approved for the treatment of metastatic renal cell carcinoma and melanoma, its suboptimal ligand binding affinity required high-dose administrations, resulting in dose-limiting toxicity such as vascular leak syndrome. To overcome the limitation of the current IL-2 therapy, a number of pharmaceutical companies have developed CD25 binding attenuated IL-2 muteins via various platform technology. These physical changes, however, accompanied a decrease in CD122-mediated signaling which was associated with cytotoxic lymphocytes expansion, leading to unsatisfied clinical consequences. In this context, we developed HM16390, a long-acting IL-2 analog with enhanced CD122 binding affinity to elicit potent anti-tumor efficacy. Furthermore, optimal binding affinity to CD25 was incorporated to prevent from unwanted toxicity. The pharmacokinetics in mice after single subcutaneous administration of HM16390 supported an extended duration of action (t1/2= 24.5 hr, bioavailability= 43.0%). To further investigate anti-tumor effect on various immunological conditions, syngeneic tumor mouse models, which are representing highly immunogenic colon cancer (CT26) and poorly immunogenic melanoma (B1F10), were chosen. After two weeks treatment in CT26 mice, complete response (CR) was observed in 89% and 100% of the mice by once weekly treatment of HM16390 at 2.1 and 8.5 mg/kg respectively, while only 22% of the mice showed CR by 5 consecutive day treatment per week of aldesleukin at 3.0 mg/kg. The cured mice had no evidence of relapse after tumor re-challenges at days 50 and 152. This immunological memory response against the CT26 tumor was demonstrated by significant increase in tumor-specific memory T cells in lymphoid organ and blood. Next, after four weeks treatment in B16F10 mice, once weekly treatment of HM16390 was well tolerated up to 42 mg/kg, and led to significant and dose-dependent retardation in tumor growth (vs syngeneic tumor vehicle) from 62.9% to 96.4% as well as dose-dependently prolonged median overall survival from 15 to 38 days (14 days in syngeneic tumor vehicle) at the dose range of 0.34 to 42 mg/kg. Of note, at doses ≥17 mg/kg, CR was observed in up to 22% of the mice. To sum up with the results, HM16390 has a dose-dependent and potent anti-tumor efficacy in murine models with the broad range of the immunogenic condition via CD122-enhanced IL-2 agonism. Citation Format: Jinyoung Kim, Jaehyuk Choi, Yu Yon Kim, Seongju Jeong, Sang Hyun Park, Sungmin Bae, Daejin Kim, In Young Choi. A long-acting and CD122-enhanced IL-2 analog, HM16390, shows a potent and durable anti-tumor effect in both syngeneic B16F10 or CT26 mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1814.

Immune checkpoint inhibitors (CPI) are widely used for cancer immunotherapy. However, the response to CPIs is dependent on phenotype of tumor microenvironment (TME). A cold tumor known as immune-excluded or -desert has shown poor response to CPIs due to an absence of effector T cells in TME. IL-2 analog, which is immune stimulator and able to recruit cancer-fighting cells into TME, may be promising therapeutic partner for overcoming a limitation of CPIs. Previously, HM16390, a long-acting CD-122-enhanced IL-2 analog, exerted dose-dependent anti-tumor activity in low immunogenic B16F10 melanoma mice. Here, we further investigated the immune cells composition in TME following HM16390 treatment and synergistic anti-tumor effect after combination with CPI. B16F10 mice were sacrificed at days 1, 3, and 8 following single subcutaneous administration of HM16390 or 5 consecutive daily administrations of aldesleukin. According to the result, HM16390 transiently increased peripheral cytokines (IFNγ and TNFα) more than aldesleukin. In line with this, we observed that the tumor-infiltrating NK/Treg ratio was significantly increased approximately 19 by treatment of HM16390 while showing 4.2 in aldesleukin treated group at Day 3. Furthermore, tumor-infiltrating CD8+/Treg ratio was also upregulated approximately 74 by treatment of HM16390 while only showing 6.1 in aldesleukin treated group at Day 8. Significantly increased pro-inflammatory molecules such as GrzB and IFNγ were also observed in HM16390 treated group compared to aldesleukin (p Citation Format: Jaehyuk Choi, Jinyoung Kim, Yu Yon Kim, Seongju Jeong, Sungmin Bae, Daejin Kim, In Young Choi. A long-acting and CD122-enhanced IL-2 analog, HM16390, synergizes with immune checkpoint inhibitor by remodeling an immune cell profile in tumor microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1831.

A generalized inversion technique (GIT) is applied to local seismic data from 90 induced earthquakes (ML 2.0–3.9) in the Fort Worth Basin (FWB) of north Texas to separate path, site, and source characteristics and to improve local seismic hazard assessment. Seismograms from three earthquake sequences on spatially separated basement faults are recorded on 66 temporary stations. Because of the lack of hard-rock recording sites within the sedimentary basin, we developed a site correction method for the appropriate GIT process. At about 30 km distance from the hypocenters, we observed a change in spectral attenuation and thus focus data analysis within this distance range. The estimated quality factors for S and P waves result in a QS that is larger than QP which we interpret as a result of concentrations of crustal pore fluids or partial fluid-saturated material along the path; an interpretation consistent with fluid-rich sedimentary rocks in the FWB. Strong site amplifications as much as five times on horizontal components reflect the thick sediments in the basin. A limited number of sites exhibit amplification or deamplification on the vertical component that limits the use of horizontal-to-vertical spectral ratio methods for characterizing the site effect relative to the site effects estimated by GIT. Stress drops for all earthquakes range from 1.18 and 21.73 MPa with a mean of 4.46 MPa, similar to values reported for tectonic intraplate events. The stress-drop values suggest that strong motion and seismic hazard from the injection-induced earthquake in the FWB are comparable to those for tectonic earthquakes. The strong site amplification and fluid effects on propagation attenuation may be crucial factors to take into account for estimating seismic hazards of induced earthquakes in sedimentary basins.

In bystander activation, pre-existing memory CD8

Background Our understanding of adaptive immune responses in COVID-19 patients is rapidly evolving, but information on the innate immune responses by natural killer (NK) cells is still insufficient. Objective We aimed to examine the phenotypic and functional status of NK cells and their changes during the course of mild and severe COVID-19. Methods We performed RNA sequencing (RNA-seq) and flow cytometric analysis of NK cells from patients with mild and severe COVID-19 at multiple time points in the course of the disease using cryopreserved peripheral blood mononuclear cells (PBMCs). Results In RNA-seq analysis, the NK cells exhibited distinctive features compared to healthy donors, with significant enrichment of pro-inflammatory cytokine-mediated signaling pathways. Intriguingly, we found that the unconventional CD56dimCD16neg (uCD56dim) NK cell population expanded in cryopreserved PBMCs from COVID-19 patients regardless of disease severity, accompanied by decreased NK cell cytotoxicity. The NK cell population was rapidly normalized alongside the disappearance of uCD56dim NK cells and the recovery of NK cell cytotoxicity in mild COVID-19 patients, but this occurred slowly in severe COVID-19 patients. Conclusion The current longitudinal study provides a deep understanding of the NK cell biology in COVID-19., Graphical abstract

Since 2008, earthquake sequences within the Fort Worth basin (FWB), north Texas, have been linked to wastewater disposal activities related to unconventional shale‐gas production. The North Texas Earthquake Study (NTXES) catalog (2008–2018), described and included herein, uses a combination of local and regional seismic networks to track significant seismic sequences in the basin. The FWB earthquakes occur along discrete faults that are relatively far apart (>30 km), allowing for more detailed study of individual sequence development. The three largest sequences (magnitude 3.6+) are monitored by local seismic networks (10 km) over time, implying that far‐field stress changes associated with fluid injection activities may be an important component to understanding the seismic hazard of induced seismicity sequences.

During microbial infection, pre-existing memory CD8+ T cells that are not specific for the infecting pathogens can be activated by cytokines without cognate antigens, termed bystander activation. Studies in mouse models and human patients demonstrate bystander activation of memory CD8+ T cells, which exerts either protective or detrimental effects on the host, depending on the infection model or disease. Research has elucidated mechanisms underlying the bystander activation of CD8+ T cells in terms of the responsible cytokines and the effector mechanisms of bystander-activated CD8+ T cells. In this Review, we describe the history of research on bystander CD8+ T cell activation as well as evidence of bystander activation. We also discuss the mechanisms and immunopathological roles of bystander activation in various microbial infections.

Tumour-unrelated, virus-specific bystander CD8We studied the characteristics of bystander CD8We show that bystander CD8Thus, the study demonstrates that bystander CD8

The heterogeneous immune landscapes of intrahepatic cholangiocarcinoma (ICC) remain largely unknown. Here we aimed to investigate the implications of tissue-resident memory (TRM)-related features of tumour-infiltrating CD8From ICC patients, we obtained blood samples and ICC surgical specimens (n = 33). We performed multicolour flow cytometry, multiplexed immunohistochemistry and RNA sequencing.When compared to peripheral CD8CD69

During microbial infection, bystander CD8

Exhausted T cells in the tumor microenvironment are major targets of immunotherapies. However, the exhaustion status of CD8

Blockade of programmed death-1 (PD-1) reinvigorates exhausted CD8(+) T cells, resulting in tumor regression in cancer patients. Recently, reinvigoration of exhausted CD8(+) T cells following PD-1 blockade was shown to be CD28-dependent in mouse models. Herein, we examined the role of CD28 in anti-PD-1 antibody-induced human T cell reinvigoration using tumor-infiltrating CD8(+) T cells (CD8(+) TILs) obtained from non-small-cell lung cancer patients. Single-cell analysis demonstrated a distinct expression pattern of CD28 between mouse and human CD8(+) TILs. Furthermore, we found that human CD28(+)CD8(+) but not CD28(–)CD8(+) TILs responded to PD-1 blockade irrespective of B7/CD28 blockade, indicating that CD28 costimulation in human CD8(+) TILs is dispensable for PD-1 blockade-induced reinvigoration and that loss of CD28 expression serves as a marker of anti-PD-1 antibody-unresponsive CD8(+) TILs. Transcriptionally and phenotypically, PD-1 blockade-unresponsive human CD28(–)PD-1(+)CD8(+) TILs exhibited characteristics of terminally exhausted CD8(+) T cells with low TCF1 expression. Notably, CD28(–)PD-1(+)CD8(+) TILs had preserved machinery to respond to IL-15, and IL-15 treatment enhanced the proliferation of CD28(–)PD-1(+)CD8(+) TILs as well as CD28(+)PD-1(+)CD8(+) TILs. Taken together, these results show that loss of CD28 expression is a marker of PD-1 blockade-unresponsive human CD8(+) TILs with a TCF1(–) signature and provide mechanistic insights into combining IL-15 with anti-PD-1 antibodies.

Background and aims Targeting costimulatory receptors with agonistic antibodies is a promising cancer immunotherapy option. We aimed to investigate costimulatory receptor expression, particularly 4-1BB (CD137 or tumor necrosis factor receptor superfamily member 9), on tumor-infiltrating CD8+ T cells (CD8+ tumor-infiltrating lymphocytes [TILs]) and its association with distinct T-cell activation features among exhausted CD8+ TILs in hepatocellular carcinoma (HCC). Approach and results Tumor tissues, adjacent nontumor tissues, and peripheral blood were collected from HCC patients undergoing surgical resection (n = 79). Lymphocytes were isolated and used for multicolor flow cytometry, RNA-sequencing, and in vitro functional restoration assays. Among the examined costimulatory receptors, 4-1BB was most prominently expressed on CD8+ TILs. 4-1BB expression was almost exclusively detected on CD8+ T cells in the tumor-especially on programmed death 1 (PD-1)high cells and not PD-1int and PD-1neg cells. Compared to PD-1int and 4-1BBneg PD-1high CD8+ TILs, 4-1BBpos PD-1high CD8+ TILs exhibited higher levels of tumor reactivity and T-cell activation markers and significant enrichment for T-cell activation gene signatures. Per-patient analysis revealed positive correlations between percentages of 4-1BBpos cells among CD8+ TILs and levels of parameters of tumor reactivity and T-cell activation. Among highly exhausted PD-1high CD8+ TILs, 4-1BBpos cells harbored higher proportions of cells with proliferative and reinvigoration potential. Our 4-1BB-related gene signature predicted survival outcomes of HCC patients in the The Cancer Genome Atlas cohort. 4-1BB agonistic antibodies enhanced the function of CD8+ TILs and further enhanced the anti-PD-1-mediated reinvigoration of CD8+ TILs, especially in cases showing high levels of T-cell activation. Conclusion 4-1BB expression on CD8+ TILs represents a distinct activation state among highly exhausted CD8+ T cells in HCC. 4-1BB costimulation with agonistic antibodies may be a promising strategy for treating HCCs exhibiting prominent T-cell activation.

During microbial infection, bystander CD8+ T cells that are not specific to infecting pathogens can be activated by cytokines, such as IL-15. However, the tissue-homing properties of bystander-activated CD8+ T cells have not been elucidated. Here, we examined the effects of IL-15 on the expression of chemokine receptors on CD8+ T cells and their migration. We found that IL-15 up-regulates CCR5 in memory CD8+ T cells in the absence of TCR stimulation and enhances CCR5-dependent migration in vitro and in vivo. IL-15-induced CCR5 up-regulation was abrogated by concurrent TCR stimulation, indicating that CCR5 is up-regulated in bystander-activated CD8+ T cells. Moreover, CCR5 signals increased proliferation and cytotoxic protein expression in IL-15-treated memory CD8+ T cells. CCR5 up-regulation in bystander-activated CD8+ T cells was associated with severe liver injury in patients with acute hepatitis A. Taken together, the results indicate that CCR5 up-regulation by IL-15 mediates the migration of bystander-activated CD8+ T cells.

Immune checkpoint inhibitors (ICIs), including anti-PD-1 and anti-CTLA-4 therapeutic agents, are now approved by the Food and Drug Administration for treatment of various types of cancer. However, the therapeutic efficacy of ICIs varies among patients and cancer types. Moreover, most patients do not develop durable antitumor responses after ICI therapy due to an ephemeral reversal of T-cell dysfunction. As co-stimulatory receptors play key roles in regulating the effector functions of T cells, activating co-stimulatory pathways may improve checkpoint inhibition efficacy, and lead to durable antitumor responses. Here, we review recent advances in our understating of co-stimulatory receptors in cancers, providing the necessary groundwork for the rational design of cancer immunotherapy.

BackgroundStimulation of 4-1BB with agonistic antibodies is a promising strategy for improving the therapeutic efficacy of immune checkpoint inhibitors (ICIs) or for overcoming resistance to ICIs. However, dose-dependent hepatotoxicity was observed in clinical trials with monoclonal anti-4-1BB agonistic antibodies due to the activation of 4-1BB signaling in liver resident Kupffer cells.MethodsTo avoid this on-target liver toxicity, we developed a novel bispecific antibody (4-1BB×PD-L1 bispecific antibody, termed “ABL503”) uniquely designed to activate 4-1BB signaling only in the context of PD-L1, while also blocking PD-1/PD-L1 signaling.ResultsFunctional evaluation using effector cells expressing both 4-1BB and PD-1 revealed superior biological activity of ABL503 compared with the combination of each monoclonal antibody. ABL503 also augmented T-cell activation in in vitro assays and further enhanced the anti-PD-L1-mediated reinvigoration of tumor-infiltrating CD8+ T cells from patients with cancer. Furthermore, in humanized PD-L1/4-1BB transgenic mice challenged with huPD-L1-expressing tumor cells, ABL503 induced superior anti-tumor activity and maintained an anti-tumor response against tumor rechallenge. ABL503 was well tolerated, with normal liver function in monkeys.ConclusionThe novel anti-4-1BB×PD-L1 bispecific antibody may exert a strong anti-tumor therapeutic efficacy with a low risk of liver toxicity through the restriction of 4-1BB stimulation in tumors.

Background and Aims Targeting costimulatory receptors with agonistic antibodies is a promising cancer immunotherapy option. We aimed to investigate costimulatory receptor expression, particularly 4‐1BB (CD137 or tumor necrosis factor receptor superfamily member 9), on tumor‐infiltrating CD8+ T cells (CD8+ tumor‐infiltrating lymphocytes [TILs]) and its association with distinct T‐cell activation features among exhausted CD8+ TILs in hepatocellular carcinoma (HCC). Approach and Results Tumor tissues, adjacent nontumor tissues, and peripheral blood were collected from HCC patients undergoing surgical resection (n = 79). Lymphocytes were isolated and used for multicolor flow cytometry, RNA‐sequencing, and in vitro functional restoration assays. Among the examined costimulatory receptors, 4‐1BB was most prominently expressed on CD8+ TILs. 4‐1BB expression was almost exclusively detected on CD8+ T cells in the tumor—especially on programmed death 1 (PD‐1)high cells and not PD‐1int and PD‐1neg cells. Compared to PD‐1int and 4‐1BBnegPD‐1high CD8+ TILs, 4‐1BBposPD‐1high CD8+ TILs exhibited higher levels of tumor reactivity and T‐cell activation markers and significant enrichment for T‐cell activation gene signatures. Per‐patient analysis revealed positive correlations between percentages of 4‐1BBpos cells among CD8+ TILs and levels of parameters of tumor reactivity and T‐cell activation. Among highly exhausted PD‐1high CD8+ TILs, 4‐1BBpos cells harbored higher proportions of cells with proliferative and reinvigoration potential. Our 4‐1BB–related gene signature predicted survival outcomes of HCC patients in the The Cancer Genome Atlas cohort. 4‐1BB agonistic antibodies enhanced the function of CD8+ TILs and further enhanced the anti‐PD‐1–mediated reinvigoration of CD8+ TILs, especially in cases showing high levels of T‐cell activation. Conclusion 4‐1BB expression on CD8+ TILs represents a distinct activation state among highly exhausted CD8+ T cells in HCC. 4‐1BB costimulation with agonistic antibodies may be a promising strategy for treating HCCs exhibiting prominent T‐cell activation.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease, in which the intestinal epithelium loses its barrier function. Given the existence of the oxygen gradient in the intestinal epithelium and that inflammation further contributes to the tissue hypoxia, we investigated the role of hypoxia-inducible factor (HIF), a transcription factor activated under hypoxic conditions in myeloid cells, in the progression of IBD. To do this, we utilized myeloid-specific knockout (KO) mice targeting HIF pathways, created by a Cre-loxP system with human MRP8 (hMRP8), an intracellular calcium-binding protein, as the myeloid promoter. By feeding 5% dextran sodium sulfate (DSS) to hMRP8 von Hippel Lindau (Vhl) KO mice, in which HIF-1α and HIF-2α are constitutively activated in myeloid cells, we found that these mice were highly susceptible to DSS-induced colitis, demonstrating greater body weight loss, increased mortality, faster onset of rectal bleeding, shortened colon length, and increased CD11b- or Gr-1-positive myeloid cells in the colon compared with wild-type (WT) mice. These parameters were restored to, if not better than, the WT levels when we examined hMRP8 Hif-1a KO mice upon 5% DSS feeding. hMRP8 Hif-2a KO mice, on the other hand, exhibited a similar degree of DSS-induced colitis to that of WT mice. Lastly, when DSS was given together with azoxymethane to induce tumorigenesis in the colon, we found that hMRP8 Hif-1a KO mice exhibited comparable levels of colorectal tumors to those of WT mice, indicating that HIF-1α in myeloid cells is dispensable for tumorigenesis. Collectively, our results suggest that HIF-1α activation in myeloid cells critically regulates IBD progression.