Development of an 8-color antibody panel for functional phenotyping of human CD8+ cytotoxic T cells from peripheral blood mononuclear cells

A tissue-engineered model of T-cell mediated oral mucosal inflammatory disease

T-cell-mediated oral mucocutaneous inflammatory conditions including oral lichen planus (OLP) are common but development of new treatments aimed at relieving symptoms and controlling OLP progression are hampered by the lack of experimental models. Here, we developed a tissue-engineered oral mucosal equivalent (OME) containing polarised T-cells to replicate OLP pathogenesis. Peripheral blood CD4+ and CD8+ T-cells were isolated, activated and polarised into Th1 and cytotoxic T-cells (Tc). OME were constructed by culturing oral keratinocytes on an oral fibroblast-populated hydrogel to produce a stratified squamous epithelium. OME stimulated with IFN-γ and TNF-α or medium from Th1 cells caused increased secretion of inflammatory cytokines/chemokines. A model of T-cell-mediated inflammatory disease was developed by combining OME on top of a Th1/Tc-containing hydrogel, followed by epithelial stimulation with IFN-γ/TNF-α. T-cell recruitment towards the epithelium was associated with increased secretion of T-cell chemoattractants CCL5, CXCL9 and CXCL10. Histological assessment showed tissue damage associated with cleaved-caspase-3 and altered laminin-5 expression. Treatment with inhibitors directed against JAK, KCa3.1 channels or clobetasol in solution and/or via a mucoadhesive patch prevented cytokine/chemokine release and tissue damage. This disease model has potential to probe for mechanisms of pathogenesis or as a test platform for novel therapeutics or treatment modalities.

Genetically modified IL2 bone-marrow-derived myeloid cells reprogram the glioma immunosuppressive tumor microenvironment

Gliomas are one of the leading causes of cancer-related death in the adolescent and young adult (AYA) population. Two-thirds of AYA glioma patients are affected by low-grade gliomas (LGGs), but there are no specific treatments. Malignant progression is supported by the immunosuppressive stromal component of the tumor microenvironment (TME) exacerbated by M2 macrophages and a paucity of cytotoxic T cells. A single intravenous dose of engineered bone-marrow-derived myeloid cells that release interleukin-2 (GEMys-IL2) was used to treat mice with LGGs. Our results demonstrate that GEMys-IL2 crossed the blood-brain barrier, infiltrated the TME, and reprogrammed the immune cell composition and transcriptome. Moreover, GEMys-IL2 extended survival in an LGG immunocompetent mouse model. Here, we report the efficacy of an in vivo approach that demonstrates the potential for a cell-mediated innate immunotherapy designed to enhance the recruitment of activated effector T and natural killer cells within the glioma TME.

Single Cell Transcriptome Analysis of Peripheral Blood Mononuclear Cells in Freshly Isolated versus Stored Blood Samples

BACKGROUND

Peripheral blood mononuclear cells (PBMCs) are widely used as a model in the study of different human diseases. There is often a time delay from blood collection to PBMC isolation during the sampling process, which can result in an experimental bias, particularly when performing single cell RNA-seq (scRNAseq) studies.

METHODS

This study examined the impact of different time periods from blood draw to PBMC isolation on the subsequent transcriptome profiling of different cell types in PBMCs by scRNAseq using the 10X Chromium Single Cell Gene Expression assay.

RESULTS

Examining the five major cell types constituting the PBMC cell population, i.e., CD4+ T cells, CD8+ T cells, NK cells, monocytes, and B cells, both common changes and cell-type-specific changes were observed in the single cell transcriptome profiling over time. In particular, the upregulation of genes regulated by NF-kB in response to TNF was observed in all five cell types. Significant changes in key genes involved in AP-1 signaling were also observed. RBC contamination was a major issue in stored blood, whereas RBC adherence had no direct impact on the cell transcriptome.

CONCLUSIONS

Significant transcriptome changes were observed across different PBMC cell types as a factor of time from blood draw to PBMC isolation and as a consequence of blood storage. This should be kept in mind when interpreting experimental results.

Expansion, persistence, and efficacy of donor memory-like NK cells infused for posttransplant relapse

BackgroundResponses to conventional donor lymphocyte infusion for postallogeneic hematopoietic cell transplantation (HCT) relapse are typically poor. Natural killer (NK) cell-based therapy is a promising modality to treat post-HCT relapse.MethodsWe initiated this ongoing phase I trial of adoptively transferred cytokine-induced memory-like (CIML) NK cells in patients with myeloid malignancies who relapsed after haploidentical HCT. All patients received a donor-derived NK cell dose of 5 to 10 million cells/kg after lymphodepleting chemotherapy, followed by systemic IL-2 for 7 doses. High-resolution profiling with mass cytometry and single-cell RNA sequencing characterized the expanding and persistent NK cell subpopulations in a longitudinal manner after infusion.ResultsIn the first 6 enrolled patients on the trial, infusion of CIML NK cells led to a rapid 10- to 50-fold in vivo expansion that was sustained over months. The infusion was well tolerated, with fever and pancytopenia as the most common adverse events. Expansion of NK cells was distinct from IL-2 effects on endogenous post-HCT NK cells, and not dependent on CMV viremia. Immunophenotypic and transcriptional profiling revealed a dynamic evolution of the activated CIML NK cell phenotype, superimposed on the natural variation in donor NK cell repertoires.ConclusionGiven their rapid expansion and long-term persistence in an immune-compatible environment, CIML NK cells serve as a promising platform for the treatment of posttransplant relapse of myeloid disease. Further characterization of their unique in vivo biology and interaction with both T cells and tumor targets will lead to improvements in cell-based immunotherapies.Trial RegistrationClinicalTrials.gov NCT04024761.FundingDunkin' Donuts, NIH/National Cancer Institute, and the Leukemia and Lymphoma Society.

Combining CTLA-4 and angiopoietin-2 blockade in patients with advanced melanoma: a phase I trial

Background

Angiogenic factors promote the growth of tumor vasculature, modulate lymphocyte trafficking into tumors, and inhibit maturation of dendritic cells. We hypothesized that MEDI3617, a human IgG1 kappa monoclonal antibody directed against human angiopoietin-2, in combination with tremelimumab (treme), an IgG2 monoclonal antibody blocking cytotoxic T-lymphocyte-associated protein- (CTLA-4), is safe in patients with advanced melanoma.

Methods

In a phase I, 3+3 dose escalation trial, patients with metastatic or unresectable melanoma received treme in combination with MEDI3617. The primary objectives of the study were safety and determination of recommended phase II dose (RP2D). The secondary objectives included determination of 6-month and 1-year overall survival and best overall response rate. Immune cell populations and soluble factors were assessed in peripheral blood and metastatic tumors using Fluorescence activated cell sorting (FACS), Luminex, and multiplexed immunofluorescence.

Results

Fifteen patients (median age: 62) were enrolled in the study (3 patients in cohort 1: treme at 10 mg/kg and MEDI3617 at 200 mg; and 12 patients in cohort 2: treme at 10 mg/kg and MEDI3617 at 600 mg). The most common all-grade treatment-related adverse events were rash, pruritus, fatigue, and extremity edema. No dose-limiting toxicities were observed. Cohort 2 was determined to be the RP2D. There were no patients with confirmed immune-related complete response or immune-related partial response. Six of 15 patients had immune-related stable disease, resulting in a disease control rate of 0.40 (95% CI 0.16 to 0.68). An increase in frequencies of circulating inducible T-cell costimulator (ICOS)⁺ and human leukocyte antigen (HLA)-DR⁺ CD4⁺ and CD8⁺ T cells and production of Interleukin-2 and Interleukin-10 was observed post therapy.

Conclusions

Tremelimumab in combination with MEDI3617 is safe in patients with advanced melanoma. Angiopoietin-2 inhibition in combination with immune checkpoint inhibition warrants further exploration.

Trial registration number

NCT02141542.

Immune modulating activity of the CHK1 inhibitor prexasertib and anti-PD-L1 antibody LY3300054 in patients with high-grade serous ovarian cancer and other solid tumors

BACKGROUND

Checkpoint kinase 1 (CHK1) has dual roles in both the DNA damage response and in the innate immune response to genotoxic stress. The combination of CHK1 inhibition and immune checkpoint blockade has the potential to enhance anti-tumoral T-cell activation.

METHODS

This was an open-label phase 1 study evaluating the CHK1 inhibitor prexasertib and the anti-PD-L1 antibody LY3300054. After a lead-in of LY3300054 (Arm A), prexasertib (Arm B) or the combination (Arm C), both agents were administered intravenously at their respective recommended phase 2 doses (RP2Ds) on days 1 and 15 of a 28-day cycle. Flow cytometry of peripheral blood was performed before and during treatment to analyze effects on immune cell populations, with a focus on T cell subsets and activation. Plasma cytokines and chemokines were analyzed using the Luminex platform.

RESULTS

Among seventeen patients enrolled, the combination was tolerable at the monotherapy RP2Ds, 105 mg/m² prexasertib and 700 mg LY3300054. Dose-limiting toxicities included one episode each of febrile neutropenia (Arm C) and grade 4 neutropenia lasting > 5 days (Arm B). One patient had immune-related AST/ALT elevation after 12 cycles. Three patients with CCNE1-amplified, high-grade serous ovarian cancer (HGSOC) achieved partial response (PR), 2 lasting > 12 months; a fourth such patient maintained stable disease > 12 months. Analysis of peripheral blood demonstrated evidence of CD8 + T-cell activation in response to treatment.

CONCLUSIONS

Prexasertib in combination with PD-L1 blockade was tolerable and demonstrated preliminary activity in CCNE1-amplified HGSOC with evidence of cytotoxic T-cell activation in patient blood samples.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03495323. Registered April 12, 2018.

High-Throughput Mass Cytometry Staining for Immunophenotyping Clinical Samples

As mass cytometry (MC) is implemented in clinical settings, the need for robust, validated protocols that reduce batch effects between samples becomes increasingly important. Here, we present a streamlined MC workflow for high-throughput staining that generates reproducible data for up to 80 samples in a single experiment by combining reference sample spike-in and palladium-based mass-tag cell barcoding. Although labor intensive, this workflow decreases experimental variables and thus reduces technical error and mitigates batch effects.

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Design and development of custom mass cytometry 35+ antibody panels

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Sample barcoding, reference sample spike-in strategy controls for batch effects

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Achieve stability and reproducibility for large-scale mass cytometry experiments

Standardized 11-color flow cytometry panel for the functional phenotyping of human T regulatory cells

T regulatory cells (Tregs) are a cell subset that can suppress immune responses to maintain homeostasis and self-tolerance. In some scenarios, the immunosuppressive nature could be associated to other pathological developments such as autoimmune diseases and cancers. Due to the importance of Tregs in disease pathogenesis, we developed and validated an 11-color flow cytometry panel for phenotypic and functional detection of Treg markers using healthy human donor peripheral blood mononuclear cells (PBMCs). Our panel contains 4 Treg surface proteins and 2 functional cytokines as well as T-lymphocyte lineage markers CD3, CD4, and CD8. Our data shows an increase in expression of markers CD25, FoxP3, CTLA4, GITR and intracellular cytokines IL4 and TGFβ when comparing unstimulated samples to CD3/CD28 bead stimulated samples. This 11-color panel can be used to functionally evaluate immunosuppressive Tregs in human PBMC samples.

Detection of clinically relevant immune checkpoint markers by multicolor flow cytometry

As checkpoint inhibitor immunotherapies gain traction among cancer researchers and clinicians, the need grows for assays that can definitively phenotype patient immune cells. Herein, we present an 8-color flow cytometry panel for lineage and immune checkpoint markers and validate it using healthy human donor peripheral blood mononuclear cells (PBMCs). Flow cytometry data was generated on a BD LSR Fortessa and supported by Luminex multiplex soluble immunoassay. Our data showed significant variation between donors at both baseline and different stages of activation, as well as a trend in increasing expression of checkpoint markers on stimulated CD4⁺ and CD8⁺ T-cells with time. Soluble immune checkpoint quantification assays revealed that LAG-3, TIM-3, CTLA-4, and PD-1 soluble isoforms are upregulated after stimulation. This 8-color flow cytometry panel, supported here by soluble immunoassay, can be used to identify and evaluate immune checkpoints on T-lymphocytes in cryopreserved human PBMC samples. This panel is ideal for characterizing checkpoint expression in clinical samples for which cryopreservation is necessary.

Anti-PD-1 Immunotherapy-Induced Flare of a Known Underlying Relapsing Vasculitis Mimicking Recurrent Cancer

Safe use of immune checkpoint blockade in patients with cancer and autoimmune disorders requires a better understanding of the pathophysiology of immunologic activation. We describe the immune correlates of reactivation of granulomatosis with polyangiitis (GPA)-an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis-in a patient with metastatic urothelial carcinoma treated with pembrolizumab. After PD-1 blockade, an inflammatory pulmonary nodule demonstrated a granulomatous, CD4+ T-cell infiltrate, correlating with increased CD4+ and CD8+ naïve memory cells in the peripheral blood without changes in other immune checkpoint receptors. Placed within the context of the existing literature on GPA and disease control, our findings suggest a key role for PD-1 in GPA self-tolerance and that selective strategies for immunotherapy may be needed in patients with certain autoimmune disorders. We further summarize the current literature regarding reactivation of autoimmune disorders in patients undergoing immune checkpoint blockade, as well as potential immunosuppressive strategies to minimize the risks of further vasculitic reactivation upon rechallenge with anti-PD-1 blockade. KEY POINTS: Nonspecific imaging findings in patients with cancer and rheumatological disorders may require biopsy to distinguish underlying pathology.Patients with rheumatologic disorders have increased risk of reactivation with PD-(L)1 immune checkpoint blockade, requiring assessment of disease status before starting treatment.Further study is needed to evaluate the efficacy of treatment regimens in preventing and controlling disease reactivation.