Temporal genomic analysis of homogeneous tumor models reveals key regulators of immune evasion in melanoma.

Low intra-tumor heterogeneity (ITH) correlates with increased patient survival and immunotherapy response. However, even highly homogeneous tumors are variably aggressive, and the immunological factors impacting aggressiveness remain understudied. Here, we analyzed the mechanisms underlying immune escape in murine tumors with low ITH.

Fc-optimized checkpoint antibodies for cancer immunotherapy.

The development of checkpoint antibodies for cancer therapy has been guided by the principle of blocking T cell inhibitory signals. Recognition of the role of the Fc domain in therapeutic activities, through the depletion of immunosuppressive populations and myeloid cell activation, prompts a shift toward the development of optimized Fc-engineered checkpoint antibodies.

Protocol for assessing murine cell doublet engagement and subsequent effects using flow cytometry and imaging flow cytometry.

Physical interactions between two immune cells or between immune and cancer cells play a major role in shaping the immune response in the tumor microenvironment, making them prime therapeutic targets for bispecific engagers. Here, we present a protocol for assessing murine cell doublet engagement and subsequent effects using flow cytometry and imaging flow cytometry. We describe steps for identifying bispecific cell engager antibodies at the cell-cell interface, doublet quantification, and characterizing cellular protein morphology and processes within the doublet.

Modeling T cell temporal response to cancer immunotherapy rationalizes development of combinatorial treatment protocols.

Successful immunotherapy relies on triggering complex responses involving T cell dynamics in tumors and the periphery. Characterizing these responses remains challenging using static human single-cell atlases or mouse models. To address this, we developed a framework for in vivo tracking of tumor-specific CD8 T cells over time and at single-cell resolution.

Bispecific dendritic-T cell engager potentiates anti-tumor immunity.

Immune checkpoint inhibition treatment using aPD-1 monoclonal antibodies is a promising cancer immunotherapy approach. However, its effect on tumor immunity is narrow, as most patients do not respond to the treatment or suffer from recurrence. We show that the crosstalk between conventional type I dendritic cells (cDC1) and T cells is essential for an effective aPD-1-mediated anti-tumor response.

FcγRIIB Is an Immune Checkpoint Limiting the Activity of Treg-Targeting Antibodies in the Tumor Microenvironment.

Preclinical murine data indicate that fragment crystallizable (Fc)-dependent depletion of intratumoral regulatory T cells (Treg) is a major mechanism of action of anti-CTLA-4. However, the two main antibodies administered to patients (ipilimumab and tremelimumab) do not recapitulate these effects. Here, we investigate the underlying mechanisms responsible for the limited Treg depletion observed with these therapies.

Fc glycoengineering of a PD-L1 antibody harnesses Fcγ receptors for increased antitumor efficacy.

FDA-approved anti-PD-L1 monoclonal antibodies (mAbs) bear the IgG1 isotype, whose scaffolds are either wild-type (e.g., avelumab) or Fc-mutated and lacking Fcγ receptor (FcγR) engagement (e.

FcyRIIB is a novel immune checkpoint in the tumor microenvironment limiting activity of Treg-targeting antibodies.

Despite pre-clinical murine data supporting T regulatory (Treg) cell depletion as a major mechanism by which anti-CTLA-4 antibodies function in vivo, the two main antibodies tested in patients (ipilimumab and tremelimumab) have failed to demonstrate similar effects. We report analogous findings in an immunocompetent murine model humanized for CTLA-4 and Fcy receptors (hCTLA-4/hFcyR mice), where both ipilimumab and tremelimumab fail to show appreciable Treg depletion. Immune profiling of the tumor microenvironment (TME) in both mice and human samples revealed upregulation of the inhibitory Fcy receptor, FcyRIIB, which limits the ability of the antibody Fc fragment of human anti-CTLA-4 antibodies to induce effective antibody dependent cellular cytotoxicty/phagocytosis (ADCC/ADCP).

Next Generation CD40 Agonistic Antibodies for Cancer Immunotherapy.

The clinical use of anti-CD40 agonist monoclonal antibodies (mAbs) is aimed at recruiting the immune system to fight the tumor cells. This approach has been demonstrated to be effective in various preclinical models. However, human CD40 Abs displayed only modest antitumor activity in cancer patients, characterized by low efficacy and dose-limiting toxicity.

Artificial Antigen Presenting Cells for Detection and Desensitization of Autoreactive T cells Associated with Type 1 Diabetes.

Autoimmune diseases and in particular type 1 diabetes rely heavily on treatments that target the symptoms rather than prevent the underlying disease. One of the barriers to better therapeutic strategies is the inability to detect and efficiently target rare autoreactive T-cell populations that are major drivers of these conditions. Here, we develop a unique artificial antigen-presenting cell (aAPC) system from biocompatible polymer particles that allows specific encapsulation of bioactive ingredients.

Therapeutic antibody activation of the glucocorticoid-induced TNF receptor by a clustering mechanism.

GITR is a TNF receptor, and its activation promotes immune responses and drives antitumor activity. The receptor is activated by the GITR ligand (GITRL), which is believed to cluster receptors into a high-order array. Immunotherapeutic agonist antibodies also activate the receptor, but their mechanisms are not well characterized.

Bispecific antibodies increase the therapeutic window of CD40 agonists through selective dendritic cell targeting.

Therapeutic use of agonistic anti-CD40 antibodies is a potentially powerful approach for activation of the immune response to eradicate tumors. However, the translation of this approach to clinical practice has been substantially restricted due to the severe dose-limiting toxicities observed in multiple clinical trials. Here, we demonstrate that conventional type 1 dendritic cells are essential for triggering antitumor immunity but not the toxicity of CD40 agonists, while macrophages, platelets and monocytes lead to toxic events.

Anti-SARS-CoV-2 antibodies elicited by COVID-19 mRNA vaccine exhibit a unique glycosylation pattern.

Messenger RNA-based vaccines against COVID-19 induce a robust anti-SARS-CoV-2 antibody response with potent viral neutralization activity. Antibody effector functions are determined by their constant region subclasses and by their glycosylation patterns, but their role in vaccine efficacy is unclear. Moreover, whether vaccination induces antibodies similar to those in patients with COVID-19 remains unknown.

Unified platform for genetic and serological detection of COVID-19 with single-molecule technology.

The COVID-19 pandemic raises the need for diverse diagnostic approaches to rapidly detect different stages of viral infection. The flexible and quantitative nature of single-molecule imaging technology renders it optimal for development of new diagnostic tools. Here we present a proof-of-concept for a single-molecule based, enzyme-free assay for detection of SARS-CoV-2.

Unified platform for genetic and serological detection of COVID-19 with single-molecule technology.

The COVID-19 pandemic raises the need for diverse diagnostic approaches to rapidly detect different stages of viral infection. The flexible and quantitative nature of single-molecule imaging technology renders it optimal for development of new diagnostic tools. Here we present a proof-of-concept for a single-molecule based, enzyme-free assay for detection of SARS-CoV-2.

Single-cell genomic approaches for developing the next generation of immunotherapies.

Recent progress in single-cell genomics urges its application in drug development, particularly of cancer immunotherapies. Current immunotherapy pipelines are focused on functional outcome and simple cellular and molecular readouts. A thorough mechanistic understanding of the cells and pathways targeted by immunotherapy agents is lacking, which limits the success rate of clinical trials.

BCR affinity differentially regulates colonization of the subepithelial dome and infiltration into germinal centers within Peyer's patches.

Gut-derived antigens trigger immunoglobulin A (IgA) immune responses that are initiated by cognate B cells in Peyer's patches (PPs). These cells colonize the subepithelial domes (SEDs) of the PPs and subsequently infiltrate pre-existing germinal centers (GCs). Here we defined the pre-GC events and the micro-anatomical site at which affinity-based B cell selection occurred in PPs.

Toxicity of an Fc-engineered anti-CD40 antibody is abrogated by intratumoral injection and results in durable antitumor immunity.

Immune stimulation has emerged as a promising approach to the treatment of neoplastic diseases. Currently approved therapeutics, such as anti-CTLA4 and anti-PD1, are primarily aimed at blocking inhibitory signaling by immune cells. An alternative and potentially synergistic approach would involve activation of immune pathways by agonism of stimulatory receptors, such as CD40.

Signaling by Antibodies: Recent Progress.

IgG antibodies mediate a diversity of immune functions by coupling of antigen specificity through the Fab domain to signal transduction via Fc-Fc receptor interactions. Indeed, balanced IgG signaling through type I and type II Fc receptors is required for the control of proinflammatory, anti-inflammatory, and immunomodulatory processes. In this review, we discuss the mechanisms that govern IgG-Fc receptor interactions, highlighting the diversity of Fc receptor-mediated effector functions that regulate immunity and inflammation as well as determine susceptibility to infection and autoimmunity and responsiveness to antibody-based therapeutics and vaccines.

Fc-Optimized Anti-CD25 Depletes Tumor-Infiltrating Regulatory T Cells and Synergizes with PD-1 Blockade to Eradicate Established Tumors.

CD25 is expressed at high levels on regulatory T (Treg) cells and was initially proposed as a target for cancer immunotherapy. However, anti-CD25 antibodies have displayed limited activity against established tumors. We demonstrated that CD25 expression is largely restricted to tumor-infiltrating Treg cells in mice and humans.

Co-targeting of Adenosine Signaling Pathways for Immunotherapy: Potentiation by Fc Receptor Engagement.

Targeting the signaling pathway of the immunosuppressive metabolite adenosine is an emerging approach for cancer immunotherapy. In this issue of Cancer Cell, Young et al. describe that co-inhibition of the adenosingenic pathway through blockade of both CD73 and A2AR enhances antitumor efficacy through distinct mechanisms.

Therapeutic Activity of Agonistic, Human Anti-CD40 Monoclonal Antibodies Requires Selective FcγR Engagement.

While engagement of the inhibitory Fcγ-receptor (FcγR) IIB is an absolute requirement for in vivo antitumor activity of agonistic mouse anti-CD40 monoclonal antibodies (mAbs), a similar requirement for human mAbs has been disputed. By using a mouse model humanized for its FcγRs and CD40, we revealed that FcγRIIB engagement is essential for the activity of human CD40 mAbs, while engagement of the activating FcγRIIA inhibits this activity. By engineering Fc variants with selective enhanced binding to FcγRIIB, but not to FcγRIIA, significantly improved antitumor immunity was observed.

Reprogramming Tumor-Associated Macrophages by Antibody Targeting Inhibits Cancer Progression and Metastasis.

Tumors are composed of multiple cell types besides the tumor cells themselves, including innate immune cells such as macrophages. Tumor-associated macrophages (TAMs) are a heterogeneous population of myeloid cells present in the tumor microenvironment (TME). Here, they contribute to immunosuppression, enabling the establishment and persistence of solid tumors as well as metastatic dissemination.