InVivoMAb human IgG1 isotype control

Immune checkpoint inhibitors (ICI) benefit some cancer patients but de novo resistance remains poorly understood. Analyzing transcriptional data from two clinical trial cohorts, GO30140 and IMbrave150, we find B cell lymphoma 9 (BCL9), a Wnt/β-catenin co-factor, associated with resistance. We develop a BCL9-targeting peptide, hsBCL9Z96, which suppresses tumor growth in combination with anti-PD-L1 ab in preclinical hepatocellular carcinoma (HCC) mouse models. Multi-omics analyses implicate targeting BCL9 inhibits BMP4 secretion and downregulates CD24 on tumor cells, reprogramming macrophages toward a tumor-suppressive phenotype and promoting macrophage phagocytosis. This in turn rejuvenates T cell immunity via enhanced macrophage-mediated antigen presentation. Our data extend our understanding of how tumor-derived Wnt/β-catenin signaling impedes the innate and adaptive immune responses in the tumor microenvironment and provide preliminary evidence that targeting BCL9 is a promising preclinical strategy to mitigate ICI resistance in HCC.

CD16a triggers antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis by natural killer (NK) cells and macrophages in anti-tumor immunity. However, CD16a undergoes cleavage by ADAM17 that dampens its anti-tumor immunity. We here develop a monoclonal antibody (F9H4) that binds to CD16a and inhibits its cleavage. F9H4 retains CD16a on the surface of NK cells and macrophages, without triggering or blocking CD16a. F9H4 also binds to and inhibits shedding of CD16b by neutrophils, and inhibits CD16a/b shedding by leukocytes in tumor samples from lung cancer patients. F9H4 promotes ADCC against lung cancer cells that are opsonized by cetuximab, an epidermal growth factor receptor antibody that engages CD16a. F9H4 synergizes with cetuximab to inhibit human lung adenocarcinoma development in immunodeficient mice reconstituted with human NK cells. F9H4 combining with cetuximab also inhibits murine lung carcinoma growth in Fc gamma receptor-humanized mice, and such effect is mediated by NK cells and macrophages. The efficacy of F9H4+cetuximab in lung cancer models is the proof-of-concept for this new approach that promotes anti-tumor functions of Fc-enabled antibodies.

Durable serological protection is maintained through the persistence of antigen-specific plasma cells (PCs), but key factors regulating the survival of nascent PCs remain unclear. Previously, we reported that bone marrow (BM) PCs partially organize into clusters that are enriched for long-lived PCs, suggesting that clusters are survival niches. Here, we report that acute blockade of a proliferation-inducing ligand (APRIL) and B cell activating factor (BAFF) using transmembrane activator and CAML interactor (TACI)-Fc rapidly disrupts clusters and mobilizes BM PCs. CD138, a surface co-receptor that is abundant on PCs and binds APRIL but not BAFF, regulates PC retention in the BM and adhesion and motility on fibronectin. Cell-intrinsic CD138 levels control competition for survival between nascent CD138low PCs and mature CD138high PCs, and enhanced survival of CD138high PCs correlates with retention in clusters. Collectively, these results indicate that PC clusters are survival niches and that dynamic competition between new and pre-existing PCs regulates the survival of new PCs and the durability of antibody responses.

Regulatory T cells (Tregs) are essential for maintaining immune balance by controlling the activation and expansion of other immune cells. Conventional suppression assays often rely on co-culturing purified cell populations, which limits multiplexed phenotyping and physiological relevance. This protocol describes a high-dimensional, single-cell assay for profiling Treg-mediated suppression within a peripheral blood mononuclear cell (PBMC) system. Tregs are first isolated by cell sorting and then reintroduced into autologous PBMCs at defined ratios. A 52-marker mass cytometry (CyTOF) panel is used to quantify cell division and phenotypic responses across multiple immune subsets. This approach allows for integrated analysis of Treg function with broad compatibility for patient profiling and drug evaluation. Key features • Quantifies Treg-mediated suppression in autologous PBMCs at single-cell resolution. • Enables high-dimensional phenotyping and proliferation tracking across multiple immune subsets using a 52-marker CyTOF panel. • Maintains physiological relevance by assessing suppression in a complex PBMC environment. • Compatible with patient-derived samples and drug perturbation experiments for translational immunology applications.

Gallbladder cancer (GBC) is the most common malignancy in the biliary system and lacks biomarkers for personalized therapy. Here, we reported that hepatic leukemia factor (HLF) was highly expressed in gallbladder cancer stem cells (CSCs) and patients with gemcitabine-resistant GBC. Mechanistic study revealed that interleukin-6 receptor (IL-6R) and transcription factor EB (TFEB) are direct target genes of HLF. The IL-6/IL-6R/signal transducer and activator of transcription 3 axis transactivates HLF expression in GBC, forming a positive feedback loop. Functional studies revealed that HLF promoted gallbladder CSCs' expansion and gemcitabine resistance via TFEB-induced autophagy. In addition, HLF drives TFEB-induced programmed death ligand 1 expression in human tumors and governs tumor immune evasion in a CD8+ T cell-dependent manner. Patient cohorts' analysis suggested that HLF levels in GBCs might determine the distinct responses to chemotherapy and immunotherapy. In conclusion, our findings demonstrated that HLF could act as a driver for gallbladder CSCs' self-renewal and drug resistance and a biomarker for individualized therapy.

Macrophages infiltrate solid tumors and either support survival or induce cancer cell death through phagocytosis or cytotoxicity. To uncover regulators of macrophage cytotoxicity towards cancer cells, we perform two co-culture CRISPR screens using CAR-macrophages targeting different tumor associated antigens. Both identify ATG9A as an important regulator of this cytotoxic activity. In vitro and in vivo, ATG9A depletion in cancer cells sensitizes them to macrophage-mediated killing. Proteomic and lipidomic analyses reveal that ATG9A deficiency impairs the cancer cell response to macrophage-induced plasma membrane damage through defective lysosomal exocytosis, reduced ceramide production, and disrupted caveolar endocytosis. Depleting non-cytotoxic macrophages using CSF1R inhibition while preventing ATG9A-mediated tumor membrane repair enhances the anti-tumor activity of therapeutic antibodies in mice. Thus, macrophage cytotoxicity plays an important role in tumor elimination during antibody or CAR-macrophage treatment, and inhibiting tumor membrane repair via ATG9A, particularly in combination with cytotoxic macrophage enrichment through CSF1R inhibition, improves tumor-targeting macrophage efficacy.

The N6-methyladenosine (m6A) methylase WTAP has been identified as a proto-oncogene in multiple cancers, including hepatocellular carcinoma (HCC). Interestingly, although WTAP expression does not differ between normal liver and HCC tissues or across different stages of HCC, patients with higher WTAP expression exhibit significantly shorter median survival times (MSTs). Here, we found that WTAP was upregulated in tumor-infiltrating CD8+ T cells, which were more enriched in HCC patients compared to the controls. HCC patients also displayed higher PD1 levels and a greater proportion of exhausted CD8+ T cells (TCF+ PD1+). Moreover, WTAP promoted PD1 expression and suppressed the proliferation and immune activity of CD8+ T cells. In the co-culture system, WTAP-overexpressing CD8+ T cells enhanced the malignancy of HCC cells. Notably, WTAP silencing further augmented the boosting effect of PD1 silencing on CD8+ T cell immune activity and strengthened its inhibitory effect on HCC cell growth. As an m6A "writer", WTAP increased the m6A level of PD1 mRNA, thereby promoting YTHDF1-mediated translation of PD1. Finally, in the HuNSG xenograft tumor model, WTAP knockdown not only alleviated CD8+ T cell exhaustion and inhibited tumor progression but also synergistically enhanced the antitumor efficacy of anti-PD1 therapy. In conclusion, WTAP promoted CD8+ T cell exhaustion and HCC progression by facilitating the m6A modification and translation of PD1 mRNA.

The lack of T cells in tumors is a major hurdle to successful immune checkpoint therapy (ICT). Therefore, therapeutic strategies promoting T cell recruitment into tumors are warranted to improve the treatment efficacy. Here, we report that Fc-optimized anti-cytotoxic T lymphocyte antigen 4 (CTLA-4) antibodies are potent remodelers of tumor vasculature that increase tumor-associated high endothelial venules (TA-HEVs), specialized blood vessels supporting lymphocyte entry into tumors. Mechanistically, this effect is dependent on the Fc domain of anti-CTLA-4 antibodies and CD4+ T cells and involves interferon gamma (IFNγ). Unexpectedly, we find that the human anti-CTLA-4 antibody ipilimumab fails to increase TA-HEVs in a humanized mouse model. However, increasing its Fc effector function rescues the modulation of TA-HEVs, promotes CD4+ and CD8+ T cell infiltration into tumors, and sensitizes recalcitrant tumors to programmed cell death protein 1 (PD-1) blockade. Our findings suggest that Fc-optimized anti-CTLA-4 antibodies could be used to reprogram tumor vasculature in poorly immunogenic cold tumors and improve the efficacy of ICT.

Tissue regenerative responses involve complex interactions between resident structural and immune cells. Recent reports indicate that accumulation of senescent cells during injury repair contributes to pathological tissue fibrosis. Using tissue-based spatial transcriptomics and proteomics, we identified upregulation of the immune checkpoint protein, cytotoxic T lymphocyte-associated protein 4 (CTLA4), on CD8+ T cells adjacent to regions of active fibrogenesis in human idiopathic pulmonary fibrosis and in a repetitive bleomycin lung injury murine model of persistent fibrosis. In humanized CTLA4-knockin mice, treatment with ipilimumab, an FDA-approved drug that targets CTLA4, resulted in accelerated lung epithelial regeneration and diminished fibrosis from repetitive bleomycin injury. Ipilimumab treatment resulted in the expansion of Cd3e+ T cells, diminished accumulation of senescent cells, and robust expansion of type 2 alveolar epithelial cells, facultative progenitor cells of the alveolar epithelium. Ex vivo activation of isolated CTLA4-expressing CD8+ cells from mice with established fibrosis resulted in enhanced cytolysis of senescent cells, suggesting that impaired immune-mediated clearance of these cells contributes to persistence of lung fibrosis in this murine model. Our studies support the concept that endogenous immune surveillance of senescent cells may be essential in promoting tissue regenerative responses that facilitate the resolution of fibrosis.

The PD-L1/PD-1 pathway is crucial for immune regulation and has become a target in cancer immunotherapy. However, in order to improve patient selection for immune checkpoint blockade (ICB) therapies, better selection criteria are needed. This study explores how the N-glycosylation of PD-L1 affects its interaction with PD-1 and ICB efficacy, focusing on its four N-linked glycosylation sites: N35, N192, N200, and N219.

Tafasitamab is a novel humanized anti-CD19 monoclonal antibody, designed for the treatment of B-cell malignancies. Our study aims to enhance the direct, non-immune-mediated, activity of tafasitamab (TAFA) with the combination of metronomic chemotherapy (mCHEMO), including vinorelbine (mVNR) and etoposide (mETO), in preclinical models of diffuse large B-cell lymphoma (DLBCL). In vitro, the 144 h exposure of thrice-weekly mVNR, daily mETO, and single-dose TAFA significantly inhibited the viability of human CD19+ DLBCL cell lines (i.e., Toledo, OCI-LY3, and SU-DHL10) in a concentration-dependent manner. In all cell lines, the concomitant treatment with TAFA and mVNR or mETO showed a marked synergism, except for TAFA + mETO on SU-DHL10 cells. The TAFA + mCHEMO treatments promoted apoptosis, and the TAFA + mVNR combination significantly inhibited, already after 24 h, the phosphorylation of GSK3α/β, mTOR, p70S6K, RPS6, and TSC2 proteins in DLBCL cells. TAFA significantly increased the VNR and ETO intracellular concentrations in all DLBCL cells after 24 h, except for ETO levels in SU-DHL10. The TAFA + mCHEMO treatment strongly reduced the ABCB1, ABCG2, and c-MYC gene expression in SU-DHL10 cells. In vivo, the TAFA + mVNR combination was well tolerated, significantly reduced the volumes of subcutaneous DLBCL masses, and increased the overall survival of mice affected by systemic DLBCL. We report additional mechanisms to enhance the direct activity of TAFA with mCHEMO synergistically in DLBCL cells in vitro and in vivo, suggesting the use of this combination schedule into future clinical trials.

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive and characterized by pronounced desmoplasia. PDAC cells communicate with cancer-associated fibroblasts (CAFs) in a paracrine/reciprocal manner, substantially promoting tumor growth and desmoplastic responses. This study highlights the critical role of anterior gradient 2 (AGR2), an endoplasmic reticulum protein disulfide isomerase, secreted by PDAC cells to activate CAFs via the Wnt signaling pathway. Activated CAFs, in turn, secrete insulin-like growth factor 1 (IGF1), which enhances AGR2 expression and secretion in PDAC cells through the IGF1 receptor (IGF1R)/c-JUN axis. Within PDAC cells, AGR2 acts as a thioredoxin, aiding the folding and cell surface presentation of IGF1R, essential for PDAC's response to CAF-derived IGF1. This reciprocal AGR2/IGF1 signaling loop intensifies desmoplasia, immunosuppression, and tumorigenesis, creating a harmful feedback loop. Targeting both pathways disrupts this interaction, reduces desmoplasia, and restores anti-tumor immunity in preclinical models, offering a promising therapeutic strategy against PDAC.

Trophoblast cell surface antigen 2 (TROP2) is highly expressed in multiple cancers relative to normal tissues, supporting its role as a target for cancer therapy. OBI-992 is an antibody-drug conjugate (ADC) derived from a novel TROP2-targeted antibody linked to the topoisomerase 1 (TOP1) inhibitor exatecan via an enzyme-cleavable hydrophilic linker, with a drug-antibody ratio of 4. This study evaluated and compared the antitumor activity of OBI-992 with that of benchmark TROP2-targeted ADCs datopotamab deruxtecan (Dato-DXd) and sacituzumab govitecan (SG) in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models. OBI-992 treatment exhibited statistically significant antitumor activity versus controls at doses of 3 and 10 mg/kg in various CDX and PDX models, demonstrating comparable or better antitumor activity with benchmark ADCs. In a large-tumor model, longer survival times were observed in OBI-992-treated mice compared with Dato-DXd-treated mice. OBI-992 treatment induced marked bystander killing of TROP2-negative cells in the presence of nearby TROP2-positive cells in both in vitro and in vivo studies. In lung adenocarcinoma CDX models with overexpression of either P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP) to mimic ATP-binding cassette transporter-mediated multidrug resistance, OBI-992 treatment maintained antitumor activity when Dato-DXd treatment became less effective. The combination of OBI-992 at suboptimal doses with either poly (ADP-ribose) polymerase (PARP) inhibitors or an immune check point inhibitor produced synergistic antitumor effects in mouse models. Taken together, these translational results support further development of OBI-992 as a cancer therapy.

Regulatory T cells (Treg) play an important role in regulating immune homeostasis in health and disease. Traditionally their suppressive function has been assayed by mixing purified cell populations, which does not provide an accurate picture of a physiologically relevant response. To overcome this limitation, we here develop 'single cell suppression profiling of human Tregs' (scSPOT). scSPOT uses a 52-marker CyTOF panel, a cell division detection algorithm, and a whole PBMC system to assess the effect of Tregs on all other cell types simultaneously. In this head-to-head comparison, we find Tregs having the clearest suppressive effects on effector memory CD8 T cells through partial division arrest, cell cycle inhibition, and effector molecule downregulation. Additionally, scSPOT identifies a Treg phenotypic split previously observed in viral infection and propose modes of action by the FDA-approved drugs Ipilimumab and Tazemetostat. scSPOT is thus scalable, robust, widely applicable, and may be used to better understand Treg immunobiology and screen for therapeutic compounds.

The activated B-cell-like subtype of diffuse large B-cell lymphoma (ABC-DLBCL) displays a worse outcome than the germinal center B-cell-like subtype (GCB-DLBCL). Currently, targeting the tumor microenvironment (TME) is the most promising approach to cure DLBCL with profound molecular heterogeneity; however, the factors affecting the tumor-promoting TME of ABC-DLBCL remain elusive. Here, cytokine interleukin-16 (IL-16) is expressed in tumor cells of ABC-DLBCL and secreted by the cleavage of active caspase-3. The serum IL-16 levels are not only a sensitive marker of treatment response, but also positively correlated with unfavorable prognosis in DLBCL patients. While IL-16 shows few direct promotional effects on tumor cell growth in vitro, its bioactive form significantly promotes tumor progression in vivo. Mechanically, IL-16 increases the infiltration of macrophages by the chemotaxis of CD4+ monocytes in the TME, enhancing angiogenesis and the expression of cytokine IL-6 and IL-10, as well as decreasing T-cell infiltration to accelerate tumor progression. This study demonstrates that IL-16 exerts a novel role in co-ordinating the bidirectional interactions between tumor progression and the TME. IMM0306, a fusion protein of CD20 mAb with the CD47 binding domain of SIRPα, reverses the tumor-promoting effects of IL-16, providing new insights into treatment strategy in ABC-DLBCL.

The cell membrane transport capacity and surface targets of multiple myeloma (MM) cells heavily influence chemotherapy and immunotherapy. Here, it is found that caveolin-1 (CAV1), a primary component of membrane lipid rafts and caveolae, is highly expressed in MM cells and is associated with MM progression and drug resistance. CAV1 knockdown decreases MM cell adhesion to stromal cells and attenuates cell adhesion-mediated drug resistance to bortezomib. CAV1 inhibition in MM cells enhances natural killer cell-mediated cytotoxicity through increasing CXCL10, SLAMF7, and CD112. CAV1 suppression reduces mitochondrial membrane potential, increases reactive oxygen species, and inhibits autophagosome-lysosome fusion, resulting in the disruption of redox homeostasis. Additionally, CAV1 knockdown enhances glutamine addiction by increasing ASCT2 and LAT1 and dysregulates glutathione metabolism. As a result of CAV1 inhibition, MM cells are more sensitive to starvation, glutamine depletion, and glutamine transporter inhibition, and grow more slowly in vivo in a mouse model treated with bortezomib. The observation that CAV1 inhibition modulated by 6-mercaptopurine, daidzin, and statins enhances the efficacy of bortezomib in vitro and in vivo highlights the translational significance of these FDA-approved drugs in improving MM outcomes. These data demonstrate that CAV1 serves as a potent therapeutic target for enhancing chemotherapy and immunotherapy for MM.

Here, we present a protocol for monitoring phagocytosis by M2-type macrophages using automated counting of phagocytic events with an imaging cytometer. We describe steps for isolating and differentiating peripheral blood mononuclear cell (PBMC)-derived monocytes into M2-like macrophages, preparing cancer cells expressing a green fluorescence marker, labeling with a pH-sensitive dye, and co-culturing with macrophages. We then outline procedures for enumerating phagocytic events using an imaging cytometer. For complete details on the use and execution of this protocol, please refer to Mishra et al.1.

The SARS-CoV-2 pandemic alerted the potential for significant harm due to future cross-species transmission of various animal coronaviruses to human. There is a significant need of antibody-based drugs to treat patients infected with previously unseen coronaviruses. In this study, we generated CV804, an antibody that binds to the S2 domain of SARS-CoV-2 spike protein, which is highly conserved across the coronavirus family and less susceptible to mutations. CV804 demonstrated broad cross-reactivities not only disease-associated human beta coronaviruses including SARS-CoV, MERS-CoV, HCoV-OC43, HCoV-HKU1 and with existing mutant strains of SARS-CoV-2 and but also with 20 representative animal-origin coronaviruses. CV804 exhibits strong antibody-dependent cellular cytotoxicity (ADCC) to SARS-CoV-2 spike protein expressed on cells in vitro, while completely lacks virus-neutralization activity. In animal models, CV804 suppressed disease progression caused by SARS-CoV-2 infection. Structural studies using HDX-MS combined with reactivity analysis with point mutants of recombinant spike proteins revealed that CV804 binds to a unique conformational epitope within the S2 domain of the spike proteins that is highly conserved among various coronaviruses. Overall, obtained data suggest that the non-neutralizing CV804 antibody recognizes the conformational structure of the spike protein displayed on the surface of infected cells and weakens the viral virulence by supporting the host immune cells' attack through ADCC activity in vivo. The CV804 epitope information revealed in this study is useful for designing pan-corona antibody therapeutics and universal coronavirus vaccines for preparing potential future pandemics.

T-cell immunoglobulin and mucin domain containing molecule-4 (TIM-4) is a scavenger receptor best known for its role in recognizing dying cells. TIM-4 orchestrates phagocytosis allowing for cellular clearance of apoptotic cells, termed efferocytosis. It was previously shown that TIM-4 directly interacts with AMPKα1, activating the autophagy pathway, leading to degradation of ingested tumors, and effectively reducing antigen presentation.