Dual CD47 and PD-L1 blockade elicits anti-tumor immunity by intratumoral CD8 T cells.

Objectives: Bispecific antibodies targeting CD47 and PD-L1 (CD47 × PD-L1 BisAb) demonstrate efficacy against a range of solid cancers. While dual blockade negates anti-CD47-mediated toxicity, the effect of combined innate and adaptive immune activation on protective tumor-resident CD8 T cells has yet to be fully elucidated.

Methods: CD8 T cell populations were tracked upon CD47 × PD-L1 BisAb treatment in an orthotopic model of murine breast cancer where anti-tumor immunity is mediated by CD8 T cells.

Retinoic acid and TGF-β orchestrate organ-specific programs of tissue residency.

Tissue-resident memory T (T) cells are integral to tissue immunity, persisting in diverse anatomical sites where they adhere to a common transcriptional framework. How these cells integrate distinct local cues to adopt the common T cell fate remains poorly understood. Here, we show that whereas skin T cells strictly require transforming growth factor β (TGF-β) for tissue residency, those in other locations utilize the metabolite retinoic acid (RA) to drive an alternative differentiation pathway, directing a TGF-β-independent tissue residency program in the liver and synergizing with TGF-β to drive T cells in the small intestine.

The Multifaceted Role of Tissue-Resident Memory T Cells.

Regionalized immune surveillance relies on the concerted efforts of diverse memory T cell populations. Of these, tissue-resident memory T (T) cells are strategically positioned in barrier tissues, where they enable efficient frontline defense against infections and cancer. However, the long-term persistence of these cells has been implicated in a variety of immune-mediated pathologies.

Divergent molecular networks program functionally distinct CD8 skin-resident memory T cells.

Skin-resident CD8 T cells include distinct interferon-γ-producing [tissue-resident memory T type 1 (T1)] and interleukin-17 (IL-17)-producing (T17) subsets that differentially contribute to immune responses. However, whether these populations use common mechanisms to establish tissue residence is unknown. In this work, we show that T1 and T17 cells navigate divergent trajectories to acquire tissue residency in the skin.

T cells: not born this way.

Human tissue-resident memory T (T) cells seeded early in life undergo an age-associated functional maturation and residency acquisition throughout childhood.

Single-cell protein expression profiling resolves circulating and resident memory T cell diversity across tissues and infection contexts.

Memory CD8 T cells can be broadly divided into circulating (T) and tissue-resident memory T (T) populations. Despite well-defined migratory and transcriptional differences, the phenotypic and functional delineation of T and T cells, particularly across tissues, remains elusive. Here, we utilized an antibody screening platform and machine learning prediction pipeline (InfinityFlow) to profile >200 proteins in T and T cells in solid organs and barrier locations.

Expansion of MAIT cells in the combined absence of NKT and γδ-T cells.

Mucosal-associated invariant T (MAIT) cells, natural killer T (NKT) cells, and γδT cells are collectively referred to as 'unconventional T cells' due to their recognition of non-peptide antigens and restriction to MHC-I-like molecules. However, the factors controlling their widely variable frequencies between individuals and organs are poorly understood. We demonstrated that MAIT cells are increased in NKT or γδT cell-deficient mice and highly expand in mice lacking both cell types.

Early immune pressure initiated by tissue-resident memory T cells sculpts tumor evolution in non-small cell lung cancer.

Tissue-resident memory T (T) cells provide immune defense against local infection and can inhibit cancer progression. However, it is unclear to what extent chronic inflammation impacts T activation and whether T cells existing in tissues before tumor onset influence cancer evolution in humans. We performed deep profiling of healthy lungs and lung cancers in never-smokers (NSs) and ever-smokers (ESs), finding evidence of enhanced immunosurveillance by cells with a T-like phenotype in ES lungs.

Intratumoral CD8 T cells with a tissue-resident memory phenotype mediate local immunity and immune checkpoint responses in breast cancer.

CD8 tumor-infiltrating lymphocytes with a tissue-resident memory T (T) cell phenotype are associated with favorable prognosis in patients with triple-negative breast cancer (TNBC). However, the relative contribution of CD8 T cells to anti-tumor immunity and immune checkpoint blockade efficacy in breast cancer remains unknown. Here, we show that intratumoral CD8 T cells in murine mammary tumors transcriptionally resemble those from TNBC patients.

Corneal tissue-resident memory T cells form a unique immune compartment at the ocular surface.

The eye is considered immune privileged such that immune responses are dampened to protect vision. As the most anterior compartment of the eye, the cornea is exposed to pathogens and can mount immune responses that recruit effector T cells. However, presence of immune memory in the cornea is not defined.

ICOS-play: dressing T cells for residency.

Efficient generation of tissue-resident memory T (T) cells is essential for long-lived immune protection in barrier tissues. Peng et al. now show that the costimulatory molecule ICOS enhances CD8 T cell lodgment by promoting early tissue retention.

A diverse fibroblastic stromal cell landscape in the spleen directs tissue homeostasis and immunity.

The spleen is a compartmentalized organ that serves as a blood filter and safeguard of systemic immune surveillance. Labyrinthine networks of fibroblastic stromal cells construct complex niches within the white pulp and red pulp that are important for tissue homeostasis and immune activation. However, the identity and roles of the global splenic fibroblastic stromal cells in homeostasis and immune responses are poorly defined.

Sphingosine 1-phosphate receptor 5 (S1PR5) regulates the peripheral retention of tissue-resident lymphocytes.

Tissue-resident memory T (TRM) cells provide long-lasting immune protection. One of the key events controlling TRM cell development is the local retention of TRM cell precursors coupled to downregulation of molecules necessary for tissue exit. Sphingosine-1-phosphate receptor 5 (S1PR5) is a migratory receptor with an uncharted function in T cells.

Discrete tissue microenvironments instruct diversity in resident memory T cell function and plasticity.

Tissue-resident memory T (T) cells are non-recirculating cells that exist throughout the body. Although T cells in various organs rely on common transcriptional networks to establish tissue residency, location-specific factors adapt these cells to their tissue of lodgment. Here we analyze T cell heterogeneity between organs and find that the different environments in which these cells differentiate dictate T cell function, durability and malleability.

Local proliferation maintains a stable pool of tissue-resident memory T cells after antiviral recall responses.

Although tissue-resident memory T cells (T cells) are critical in fighting infection, their fate after local pathogen re-encounter is unknown. Here we found that skin T cells engaged virus-infected cells, proliferated in situ in response to local antigen encounter and did not migrate out of the epidermis, where they exclusively reside. As a consequence, secondary T cells formed from pre-existing T cells, as well as from precursors recruited from the circulation.

Chemokine Receptor-Dependent Control of Skin Tissue-Resident Memory T Cell Formation.

Infection or inflammation of the skin recruits effector CD8 T cells that enter the epidermis and form populations of long-lived tissue-resident memory T (T) cells. These skin T cells migrate within the constrained epidermal environment by extending multiple dynamic dendritic projections and squeezing between keratinocytes to survey the tissue for pathogens. In this study, we examined the signals required for this distinctive mode of T cell migration by inhibiting key cytoskeletal components and performing intravital two-photon microscopy to visualize T cell behavior.

GM-CSF signalling blockade and chemotherapeutic agents act in concert to inhibit the function of myeloid-derived suppressor cells .

Immune evasion is a recently defined hallmark of cancer, and immunotherapeutic approaches that stimulate an immune response to tumours are gaining recognition. However tumours may evade the immune response and resist immune-targeted treatment by promoting an immune-suppressive environment and stimulating the differentiation or recruitment of immunosuppressive cells. Myeloid-derived suppressor cells (MDSC) have been identified in a range of cancers and are often associated with tumour progression and poor patient outcomes.

The contribution of inflammasome components on macrophage response to surface nanotopography and chemistry.

Implantable devices have become an established part of medical practice. However, often a negative inflammatory host response can impede the integration and functionality of the device. In this paper, we interrogate the role of surface nanotopography and chemistry on the potential molecular role of the inflammasome in controlling macrophage responses.

GD2-specific CAR T Cells Undergo Potent Activation and Deletion Following Antigen Encounter but can be Protected From Activation-induced Cell Death by PD-1 Blockade.

Chimeric antigen receptor (CAR) T cells have shown great promise in the treatment of hematologic malignancies but more variable results in the treatment of solid tumors and the persistence and expansion of CAR T cells within patients has been identified as a key correlate of antitumor efficacy. Lack of immunological "space", functional exhaustion, and deletion have all been proposed as mechanisms that hamper CAR T-cell persistence. Here we describe the events following activation of third-generation CAR T cells specific for GD2.

Inflammasome components ASC and AIM2 modulate the acute phase of biomaterial implant-induced foreign body responses.

Detailing the inflammatory mechanisms of biomaterial-implant induced foreign body responses (FBR) has implications for revealing targetable pathways that may reduce leukocyte activation and fibrotic encapsulation of the implant. We have adapted a model of poly(methylmethacrylate) (PMMA) bead injection to perform an assessment of the mechanistic role of the ASC-dependent inflammasome in this process. We first demonstrate that ASC(-/-) mice subjected to PMMA bead injections had reduced cell infiltration and altered collagen deposition, suggesting a role for the inflammasome in the FBR.

The Role of Surface Nanotopography and Chemistry on Primary Neutrophil and Macrophage Cellular Responses.

Synthetic materials employed for enhancing, replacing, or restoring biological functionality may be compromised by the host immune responses that they evoke. Surface modification has attracted substantial attention as a tool to modulate the host response to synthetic materials; however, how surface nanotopography combined with chemistry affects immune effector cell responses is still poorly understood. To address this open question, a unique set of model surfaces with controlled surface nanotopography in the range of 16, 38, and 68 nm has been generated.