scholarly journals IMMU-23. A NOVEL MASS CYTOMETRY-BASED MULTI-PARAMETER CHARACTERIZATION OF NEOANTIGEN-REACTIVE CD8+ T-CELLS IN PATIENTS PARTICIPATING IN PNOC007 H3.3K27M PEPTIDE VACCINE CLINICAL TRIAL

2020 ◽  
Vol 22 (Supplement_3) ◽  
pp. iii364-iii365
Author(s):  
Jared Taitt ◽  
Takahide Nejo ◽  
Payal Watchmaker ◽  
Neil Almeida ◽  
Kaori Okada ◽  
...  

Abstract BACKGROUND We have identified an HLA-A*02:01-restricted neoantigen epitope encompassing the H3.3K27M mutation and implemented a multi-center clinical trial of the peptide vaccine through the Pacific Pediatric Neuro-Oncology Consortium (PNOC007) for patients with diffuse midline glioma (DMG), including diffuse intrinsic pontine glioma (DIPG). We sought to characterize vaccine-reactive CD8+T-cells subpopulations using their precise activation and developmental status to find their associations with clinical outcomes. METHODS Mass cytometry (CyTOF) analysis was performed on patient-derived peripheral blood mononuclear cells collected at baseline as well as pre-specified time points throughout the study. Each cell subtype was characterized via tSNE-clustering based on their expression profiles and quantified as a fraction of total CD45+cells. H3.3K27M-reactive CD8+T-cells were evaluated using an H3.3K27M-HLA-A2 dextramer along with a panel of T-cell and myeloid markers. RESULTS Among all 29 patients enrolled, we analyzed samples from all 19 DIPG and 9 of 10 non-brainstem DMG cases, of which 18 had longitudinal samples available (range: 2–5). Utilizing a novel CyTOF-based immuno-monitoring platform, the expansion of H3.3K27M-reactive CD8+T-cells, defined as a 25% increase at any time-point relative to baseline, was observed in 7 of these 18 patients. Survival analyses indicated that the expansion of H3.3K27M-reactive CD8+T-cells, particularly the effector-memory phenotype, positively correlated with longer overall survival (OS) (median: 16.1 vs 9.7 months, p=0.03), whereas an abundance of early and monocytic myeloid-derived suppressor cells at baseline correlated with shorter OS among DIPG patients (9.5 vs 14.3 months, p=0.002). CONCLUSION Our novel immuno-monitoring approach offers insight into how vaccine-induced immune responses impact clinical outcomes.

2019 ◽  
Vol 21 (Supplement_6) ◽  
pp. vi125-vi125
Author(s):  
Jared Taitt ◽  
Payal Watchmaker ◽  
Takahide Nejo ◽  
Neil Almeida ◽  
Kaori Okada ◽  
...  

Abstract Diffuse midline glioma (DMG), including diffuse intrinsic pontine glioma (DIPG) constitutes up to 20% of pediatric brain cancer and has a median survival of less than one year. We have identified a novel HLA-A*02:01-restricted neoantigen epitope encompassing the H3.3K27M mutation and implemented a pilot clinical trial through the Pacific Pediatric Neuro-Oncology Consortium (PNOC007). Newly diagnosed DIPG patients who are HLA-A2+ and H3.3K27M+ underwent radiation therapy, and then received the H3.3K27M peptide vaccine and tetanus toxoid (TT) peptide emulsified in Montanide in combination with poly-ICLC every 3 weeks for a total of 24 weeks. Our objective is to characterize vaccine-induced H3.3K27M-specific T-cell subpopulations in peripheral blood mononuclear cells through the evaluation of surface markers correlated with activation, memory, and exhaustion phenotypes utilizing a novel H3.3K27M-specific dextramer-based mass cytometry method. Through this approach, the temporal expansion of vaccine-reactive CD8+ T-cells was observed in all of patients (n = 4) who completed a minimum of 18 weeks on the study. These T-cells were subsequently stratified into discrete clusters on a tSNE plot using canonical CD8+ T-cell markers. Resultant clusters were further classified by their expression profiles, revealing distinct effector memory and exhausted subpopulations. Chronological monitoring of these groups indicates the time course-dependent development and persistence of vaccine-reactive exhausted and effector memory CD8+ T-cells in 75% of patients analyzed. Furthermore, a comparative analysis of myeloid subpopulations revealed an inverse correlation between the expansion of monocytic myeloid-derived suppressor cells (M-MDSCs) and length of enrollment in the trial. Future plans include the analysis of regulatory T-cells (Tregs) and MDSCs of all enrolled patients to solidify the relationship between the length of stay on the study and prevalence of immunosuppressive populations. This methodology offers insight into the progression of vaccine-induced patient immune responses and exhibits promise as a platform that may be extrapolated to other immunotherapies.


Cancers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 627 ◽  
Author(s):  
Nada Chaoul ◽  
Serena Mancarella ◽  
Luigi Lupo ◽  
Gianluigi Giannelli ◽  
Francesco Dituri

Different subsets of lymphocytes have the capacity to promote or counteract the progression of solid cancers, including hepatocellular carcinoma (HCC). Therefore, to determine the infiltrative ability and functional status of major immune cell subtypes into tumor may lead to novel insights from the perspective of immunotherapy. After obtaining single cell suspensions from freshly collected specimens of HCC tumor, along with paired peritumor tissues and peripheral blood mononuclear cells (PBMCs) from 14 patients, we flow-cytometrically identified and quantified the relative frequencies of lymphocyte subsets within the tissues of origin. We found that the recruitment in the tumor of cytotoxic cells, namely the terminally differentiated CD4+ and CD8+ T cells (TEFF), is impaired, whereas the effector memory CD4+ T cells (TEM) are more attracted in this site. Concerning the other subsets, the frequency of NK CD56hi and NKT CD56hi cells infiltration in the tumor is increased, whereas that of NKT CD56low is reduced. Although CD4+ and CD8+ T cells settled in the tumor show a higher degree of activation than the circulating counterpart, they occur with a more exhausted phenotype. Overall, these data demonstrate the prevalently immunosuppressive nature of HCC microenvironment, and prompt us to search for strategies to enhance the activity of anti-tumor immune cell subsets.


Blood ◽  
2000 ◽  
Vol 96 (5) ◽  
pp. 1994-1995 ◽  
Author(s):  
Masako Moriuchi ◽  
Hiroyuki Moriuchi

Abstract Although it is widely believed that viral clearance is mediated principally by the destruction of infected cells by cytotoxic T cells, noncytolytic antiviral activity of CD8+ T cells may play a role in preventing the progression to disease in infections with immunodeficiency viruses and hepatitis B virus. We demonstrate here that (1) replication of human T-lymphotropic virus type I (HTLV-I) is more readily detected from CD8+ T-cell–depleted (CD8−) peripheral blood mononuclear cells (PBMCs) of healthy HTLV-I carriers than from unfractionated PBMCs, (2) cocultures of CD8− PBMCs with autologous or allogeneic CD8+ T cells suppressed HTLV-I replication, and (3) CD8+ T-cell anti-HTLV-I activity is not abrogated intrans-well cultures in which CD8+ cells are separated from CD8− PBMCs by a permeable membrane filter. These results suggest that class I-unrestricted noncytolytic anti–HTLV-I activity is mediated, at least in part by a soluble factor(s), and may play a role in the pathogenesis of HTLV-I infection.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Nirupama D. Verma ◽  
Andrew D. Lam ◽  
Christopher Chiu ◽  
Giang T. Tran ◽  
Bruce M. Hall ◽  
...  

AbstractResting and activated subpopulations of CD4+CD25+CD127loT regulatory cells (Treg) and CD4+CD25+CD127+ effector T cells in MS patients and in healthy individuals were compared. Peripheral blood mononuclear cells isolated using Ficoll Hypaque were stained with monoclonal antibodies and analysed by flow cytometer. CD45RA and Foxp3 expression within CD4+ cells and in CD4+CD25+CD127loT cells identified Population I; CD45RA+Foxp3+, Population II; CD45RA−Foxp3hi and Population III; CD45RA−Foxp3+ cells. Effector CD4+CD127+ T cells were subdivided into Population IV; memory /effector CD45RA− CD25−Foxp3− and Population V; effector naïve CD45RA+CD25−Foxp3−CCR7+ and terminally differentiated RA+ (TEMRA) effector memory cells. Chemokine receptor staining identified CXCR3+Th1-like Treg, CCR6+Th17-like Treg and CCR7+ resting Treg. Resting Treg (Population I) were reduced in MS patients, both in untreated and treated MS compared to healthy donors. Activated/memory Treg (Population II) were significantly increased in MS patients compared to healthy donors. Activated effector CD4+ (Population IV) were increased and the naïve/ TEMRA CD4+ (Population V) were decreased in MS compared to HD. Expression of CCR7 was mainly in Population I, whereas expression of CCR6 and CXCR3 was greatest in Populations II and intermediate in Population III. In MS, CCR6+Treg were lower in Population III. This study found MS is associated with significant shifts in CD4+T cells subpopulations. MS patients had lower resting CD4+CD25+CD45RA+CCR7+ Treg than healthy donors while activated CD4+CD25hiCD45RA−Foxp3hiTreg were increased in MS patients even before treatment. Some MS patients had reduced CCR6+Th17-like Treg, which may contribute to the activity of MS.


Author(s):  
L. Sams ◽  
S. Kruger ◽  
V. Heinemann ◽  
D. Bararia ◽  
S. Haebe ◽  
...  

Abstract Purpose This pilot study aimed on generating insight on alterations in circulating immune cells during the use of FOLFIRINOX and gemcitabine/nab-paclitaxel in pancreatic ductal adenocarcinoma (PDAC). Patients and methods Peripheral blood mononuclear cells were isolated before and 30 days after initiation of chemotherapy from 20 patients with advanced PDAC. Regulatory T cells (FoxP3+) and immune checkpoints (PD-1 and TIM-3) were analyzed by flow cytometry and immunological changes were correlated with clinical outcome. Results Heterogeneous changes during chemotherapy were observed in circulating T-cell subpopulations with a pronounced effect on PD-1+ CD4+/CD8+ T cells. An increase in FoxP3+ or PD-1+ T cells had no significant effect on survival. An increase in TIM3+/CD8+ (but not TIM3+/CD4+) T cells was associated with a significant inferior outcome: median progression-free survival in the subgroup with an increase of TIM-3+/CD8+ T cells was 6.0 compared to 14.0 months in patients with a decrease/no change (p = 0.026); corresponding median overall survival was 13.0 and 20.0 months (p = 0.011), respectively. Conclusions Chemotherapy with FOLFIRNOX or gemcitabine/nab-paclitaxel induces variable changes in circulating T-cell populations that may provide prognostic information in PDAC.


2021 ◽  
Author(s):  
Emily Stephenson ◽  
◽  
Gary Reynolds ◽  
Rachel A. Botting ◽  
Fernando J. Calero-Nieto ◽  
...  

AbstractAnalysis of human blood immune cells provides insights into the coordinated response to viral infections such as severe acute respiratory syndrome coronavirus 2, which causes coronavirus disease 2019 (COVID-19). We performed single-cell transcriptome, surface proteome and T and B lymphocyte antigen receptor analyses of over 780,000 peripheral blood mononuclear cells from a cross-sectional cohort of 130 patients with varying severities of COVID-19. We identified expansion of nonclassical monocytes expressing complement transcripts (CD16+C1QA/B/C+) that sequester platelets and were predicted to replenish the alveolar macrophage pool in COVID-19. Early, uncommitted CD34+ hematopoietic stem/progenitor cells were primed toward megakaryopoiesis, accompanied by expanded megakaryocyte-committed progenitors and increased platelet activation. Clonally expanded CD8+ T cells and an increased ratio of CD8+ effector T cells to effector memory T cells characterized severe disease, while circulating follicular helper T cells accompanied mild disease. We observed a relative loss of IgA2 in symptomatic disease despite an overall expansion of plasmablasts and plasma cells. Our study highlights the coordinated immune response that contributes to COVID-19 pathogenesis and reveals discrete cellular components that can be targeted for therapy.


2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 1323.1-1323
Author(s):  
R. Reitsema ◽  
R. Hid Cadena ◽  
W. Abdulahad ◽  
A. Boots ◽  
P. Heeringa ◽  
...  

Background:Giant cell arteritis (GCA) is the most frequent form of systemic vasculitis affecting the large- and medium-sized vessels. The involvement of innate immune cells and CD4+ T cells in the pathogenesis of GCA has been extensively studied. Interestingly, recent findings suggest a role for CD8+ T cells in disease development (1). However, CD8+ subsets and their functional capacities have not yet been studied in detail.Objectives:This study aims to characterize the phenotype and proliferative capacity of CD8+ T cells in newly diagnosed GCA patients and GCA patients in remission compared to healthy age- and sex- matched controls.Methods:To determine the phenotype of CD8+ T cells in GCA, newly diagnosed, untreated GCA patients (baseline, n=14), GCA patients in stable glucocorticoid-free remission (GC-FR, n=10) and age- and sex-matched healthy controls (HCs, n=18) were enrolled. Peripheral blood mononuclear cells (PBMCs) were stained with fluorochrome-conjugated antibodies directed against CD3, CD4, CD8, CCR7, CD45RO, Ki-67, CD69 and CD25 and analyzed by flow cytometry. The following differentiation subsets were defined: CD8+ T naive (CD45RO-CCR7+), central memory (TCM, CD45RO+CCR7+), effector memory (TEM, CD45RO+CCR7-) and effector memory re-expressing CD45RA (TEMRA, CD45RO-CCR7-) cells. Secondly, the proliferative capacity of CD8+ T cells was determined in isolated CD3+ T cells of 10 GCA baseline, 10 GCA GC-FR patients and 19 HCs after 5 days of stimulation with plate-bound anti-CD3 or anti-CD3 plus soluble anti-CD28 using a dye-based proliferation assay.Results:A reduced frequency of CD8+ TEMcells was found in GCA baseline patients compared to HCs (p=0.025). Furthermore, a higher frequency of Ki-67+ cells was detected among CD8+ TEMcells in GCA baseline patients than in HCs (p=0.0007), suggesting a higher proliferative activityin vivo.In addition,in vitrostimulation with anti-CD3 and anti-CD3+anti-CD28 led to higher percentages of divided CD8+ T cells in GCA baseline and GC-FR patients than in HCs (p<0.05). Moreover, the frequencies of CD8+ TEMRAcells and the percentage of divided CD8+ T cells upon CD3 stimulation strongly correlated in GCA baseline patients (R=0.79, p=0.009) and GCA GC-FR patients (R=0.67, p=0.039) but not in HCs (R=0.31, p=0.25).Conclusion:GCA baseline patients demonstrate a higher frequency of proliferating circulating CD8+ TEMcells, defined by Ki-67 expression, than HCs. In addition, functional data on induced proliferative capacity suggest that CD8+ T cells from GCA baseline patients are more rapidly activated by crosslinking CD3 and CD3+CD28, suggesting either reduced regulation in these patients or more intrinsic threshold changes. Furthermore, the induced proliferative capacity is also elevated in patients in stable glucocorticoid-free remission. Whether the increased proliferative capacity of total CD8+ T cells in GCA patients is causally linked to the increased frequencies of CD8+ TEMRAcells in these patients requires further investigation.References:[1]Samson M, Ly KH, Tournier B, Janikashvili N, Trad M, Ciudad M, et al. Involvement and prognosis value of CD8+ T cells in giant cell arteritis. J Autoimmun. 2016;72:73–83.Disclosure of Interests:Rosanne Reitsema: None declared, Rebeca Hid Cadena: None declared, Wayel Abdulahad: None declared, Annemieke Boots Consultant of: Grünenthal Gmbh until 2017, Peter Heeringa: None declared, Elisabeth Brouwer Consultant of: Roche (consultancy fee 2017 and 2018 paid to the UMCG), Speakers bureau: Roche (2017 and 2018 paid to the UMCG)


Author(s):  
jia liu ◽  
Xuecheng Yang ◽  
Hua Wang ◽  
Ziwei Li ◽  
Hui Deng ◽  
...  

The coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects millions of people and killed hundred-thousands of individuals. While acute and intermediate interactions between SARS-CoV-2 and the immune system have been studied extensively, long-term impacts on the cellular immune system remained to be analyzed. Here, we comprehensively characterized immunological changes in peripheral blood mononuclear cells in 49 COVID-19 convalescent individuals (CI) in comparison to 27 matched SARS-CoV-2 unexposed individuals (UI). Despite recovery from the disease for more than 2 months, CI showed significant decreases in frequencies of invariant NKT and NKT-like cells compared to UI. Concomitant with the decrease in NKT-like cells, an increase in the percentage of Annexin V and 7-AAD double positive NKT-like cells was detected, suggesting that the reduction in NKT-like cells results from cell death months after recovery. Significant increases in regulatory T cell frequencies, TIM-3 expression on CD4 and CD8 T cells, as well as PD-L1 expression on B cells were also observed in CI, while the cytotoxic potential of T cells and NKT-like cells, defined by GzmB expression, was significantly diminished. However, both CD4 and CD8 T cells of CI showed increased Ki67 expression and were fully capable to proliferate and produce effector cytokines upon TCR stimulation. Collectively, we provide the first comprehensive characterization of immune signatures in patients recovering from SARS-CoV-2 infection, suggesting that the cellular immune system of COVID-19 patients is still under a sustained influence even months after the recovery from disease.


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