scholarly journals Improving immunotherapy for high grade glioma

2021 ◽  
Author(s):  
◽  
Martin Kent Hunn
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Mouse Model ◽  
Mononuclear Cells ◽  
Tumour Cells ◽  
Treatment Modalities ◽  
Full Potential ◽  
Promising Alternative ◽  
Tumour Immunity

<p>Glioblastoma multiforme (GBM) is a malignant primary brain tumour that is almost always fatal. Conventional treatment modalities are limited by toxicity. T cell-based immunotherapy is a promising alternative that has the potential to specifically target tumour cells.  The author of this thesis was a principal investigator for a recently completed Phase I clinical trial in which patients with recurrent GBM were treated with surgery, dendritic cell-based immunotherapy and chemotherapy. In addition to conducting the trial in collaboration with others, the author used peripheral blood mononuclear cells from trial participants to assess anti-tumour immune responses before and after treatment. A broad correlation was observed between clinical outcome and anti-tumour immunity, with sustained progression-free survival occurring in two patients with baseline responses that persisted or increased after treatment. However, the overall clinical benefit was modest. For progress to be made, there is a need to develop a more potent vaccine.  With this in mind, a novel “Glioma-Gal” vaccine was devised and tested in an orthotopic mouse model of glioma, This simple vaccine consisted of irradiated autologous tumour cells pulsed with the glycolipid alpha-galactosylceramide, an immunoadjuvant that induces invariant Natural Killer T cells to licence endogenous dendritic cells. The vaccine was shown to be effective in a therapeutic setting when accompanied by depletion of regulatory T cells. Mechanistically, vaccine efficacy was dependent on CD4 T cells and the mediastinal lymph node was shown to be an important site of T cell priming. It was further shown that components of the immune system necessary for the vaccine to work were present and competent in a cohort of GBM patients.  The final chapters explore the idea of enhancing the therapeutic benefit of this vaccine by targeting certain tumour cell subsets or phenotypes. Cancer stem cells (CSC) are proposed to be a subset of tumour cells with a unique capacity for initiating and maintaining tumours. Eliminating these cells may therefore be both necessary and sufficient to achieve cure. Using the same mouse model, a variety of methods were assessed for their ability to isolate or enrich for a CSC subset. Of these, culture in serum-free medium in the presence of certain growth factors was shown to enrich for a more stem cell-like phenotype. However, a vaccine constructed from these stem cell-like cells was not more effective than the standard vaccine. Next, the author tested the hypothesis that a vaccine manipulated to target chemoresistant cells would be more effective than standard vaccine when used in combination with chemotherapy. However, the modified vaccine showed no advantage over standard vaccine in this model. In the course of these experiments, synergy was observed between the vaccine and the chemotherapy agent doxorubicin. The mechanism responsible for this supra-additive effect remains undetermined but is most likely due to an immunomodulatory effect of low dose doxorubicin.  The Glioma-Gal vaccine design holds promise but more studies are needed to realise the full potential of this approach. The data presented in the thesis did not support targeting CSC or chemoresistant cells as ways of achieving this. In contrast, combining the vaccine with immunomodulation was effective and merits further exploration.</p>

scholarly journals Improving immunotherapy for high grade glioma

2021 ◽  
Author(s):  
◽  
Martin Kent Hunn
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Mouse Model ◽  
Mononuclear Cells ◽  
Tumour Cells ◽  
Treatment Modalities ◽  
Full Potential ◽  
Promising Alternative ◽  
Tumour Immunity

<p>Glioblastoma multiforme (GBM) is a malignant primary brain tumour that is almost always fatal. Conventional treatment modalities are limited by toxicity. T cell-based immunotherapy is a promising alternative that has the potential to specifically target tumour cells.  The author of this thesis was a principal investigator for a recently completed Phase I clinical trial in which patients with recurrent GBM were treated with surgery, dendritic cell-based immunotherapy and chemotherapy. In addition to conducting the trial in collaboration with others, the author used peripheral blood mononuclear cells from trial participants to assess anti-tumour immune responses before and after treatment. A broad correlation was observed between clinical outcome and anti-tumour immunity, with sustained progression-free survival occurring in two patients with baseline responses that persisted or increased after treatment. However, the overall clinical benefit was modest. For progress to be made, there is a need to develop a more potent vaccine.  With this in mind, a novel “Glioma-Gal” vaccine was devised and tested in an orthotopic mouse model of glioma, This simple vaccine consisted of irradiated autologous tumour cells pulsed with the glycolipid alpha-galactosylceramide, an immunoadjuvant that induces invariant Natural Killer T cells to licence endogenous dendritic cells. The vaccine was shown to be effective in a therapeutic setting when accompanied by depletion of regulatory T cells. Mechanistically, vaccine efficacy was dependent on CD4 T cells and the mediastinal lymph node was shown to be an important site of T cell priming. It was further shown that components of the immune system necessary for the vaccine to work were present and competent in a cohort of GBM patients.  The final chapters explore the idea of enhancing the therapeutic benefit of this vaccine by targeting certain tumour cell subsets or phenotypes. Cancer stem cells (CSC) are proposed to be a subset of tumour cells with a unique capacity for initiating and maintaining tumours. Eliminating these cells may therefore be both necessary and sufficient to achieve cure. Using the same mouse model, a variety of methods were assessed for their ability to isolate or enrich for a CSC subset. Of these, culture in serum-free medium in the presence of certain growth factors was shown to enrich for a more stem cell-like phenotype. However, a vaccine constructed from these stem cell-like cells was not more effective than the standard vaccine. Next, the author tested the hypothesis that a vaccine manipulated to target chemoresistant cells would be more effective than standard vaccine when used in combination with chemotherapy. However, the modified vaccine showed no advantage over standard vaccine in this model. In the course of these experiments, synergy was observed between the vaccine and the chemotherapy agent doxorubicin. The mechanism responsible for this supra-additive effect remains undetermined but is most likely due to an immunomodulatory effect of low dose doxorubicin.  The Glioma-Gal vaccine design holds promise but more studies are needed to realise the full potential of this approach. The data presented in the thesis did not support targeting CSC or chemoresistant cells as ways of achieving this. In contrast, combining the vaccine with immunomodulation was effective and merits further exploration.</p>

Impaired Alloantigen Presenting Activity of Cord Blood Nucleated Cells.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2203-2203
Author(s):  
Sandeep Chunduri ◽  
Dolores Mahmud ◽  
Javaneh Abbasian ◽  
Damiano Rondelli
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Cord Blood ◽  
Mononuclear Cells ◽  
Ex Vivo ◽  
Solid Organ Transplantation ◽  
T Cell Response ◽  
Solid Organ ◽  
Cd34 Cells

Abstract Transplantation of HLA-mismatched cord blood (CB) nucleated cells has limited risk of severe acute graft-versus-host disease and graft rejection. This may depend on naïve T cells not yet exposed to many antigens and on immature antigen-presenting cells (APC) not delivering appropriate signals to allogeneic T cells. In order to test the APC activity of human circulating CB cells in-vitro, we initially used irradiated CB mononuclear cells (MNC) or immunomagnetically selected CD34+ cells, CD133+ cells, or CD14+ monocytes to stimulate the proliferative response of incompatible blood T cells in mixed leukocyte culture (MLC). CB MNC failed to induce allogeneic T cell proliferation, while CD34+ and CD133+ progenitors or CD14+ monocytes induced potent T cell alloresponses. Nevertheless, since allogeneic T cell response was not restored after depletion of CD3+ cells in the CB, nor the add-back of irradiated CB MNC to CD34+ or CD14+ stimulators inhibited allo-T cells, a direct suppressive effect of CB MNC was excluded. Allogeneic peripheral blood cytotoxic T-lymphocyte (CTL) responses were not induced after 7 days of stimulation with irradiated CB MNC, although after 4 weekly rechallenges with CB MNC, on average a 23% lysis of antigen-specific CB PHA-blasts was observed at the highest effector:target ratio (50:1). To test the tolerogenic potential of CB MNC, T cells initially exposed to CB MNC were rechallenged in secondary MLC with CB MNC, or CD34+ cells, or monocyte-derived dendritic cells (Mo-DC) generated in liquid culture with GM-CSF and IL-4. Allogeneic T cells were still unresponsive upon rechallenge with CB MNC, but proliferated upon 3 days of restimulation with CD34+ cells or Mo-DC from the same CB. Surprisingly, the supernatant of these latter MLCs did inhibit completely a 3rd party MLC. Instead, the supernatant of blood T cells that had been activated by CB CD34+ cells or Mo-DC both in primary and secondary MLC did not. These results show an impaired allo-APC activity of CB MNC but not CB CD34+ cells, and suggest that T cells releasing immunosuppressive cytokines may be activated by CB MNC and then expanded by a second more potent stimulation with professional APC. This hypothesis could explain the sustained engraftment of HLA-mismatched CB stem cell transplants in humans. Based on these results, the in-vivo or ex-vivo downregulation of T cell alloreactivity induced by CB MNC will be tested in experimental models of stem cell, as well as solid organ transplantation.

scholarly journals The Role of γδ T Cells as a Line of Defense in Viral Infections after Allogeneic Stem Cell Transplantation: Opportunities and Challenges

Viruses ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 117
Author(s):  
Anke Janssen ◽  
Eline van Diest ◽  
Anna Vyborova ◽  
Lenneke Schrier ◽  
Anke Bruns ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Allogeneic Stem Cell Transplantation ◽  
Therapeutic Potential ◽  
Γδ T Cells ◽  
Full Potential ◽  
Γδ T Cell

In the complex interplay between inflammation and graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (allo-HSCT), viral reactivations are often observed and cause substantial morbidity and mortality. As toxicity after allo-HSCT within the context of viral reactivations is mainly driven by αβ T cells, we describe that by delaying αβ T cell reconstitution through defined transplantation techniques, we can harvest the full potential of early reconstituting γδ T cells to control viral reactivations. We summarize evidence of how the γδ T cell repertoire is shaped by CMV and EBV reactivations after allo-HSCT, and their potential role in controlling the most important, but not all, viral reactivations. As most γδ T cells recognize their targets in an MHC-independent manner, γδ T cells not only have the potential to control viral reactivations but also to impact the underlying hematological malignancies. We also highlight the recently re-discovered ability to recognize classical HLA-molecules through a γδ T cell receptor, which also surprisingly do not associate with GVHD. Finally, we discuss the therapeutic potential of γδ T cells and their receptors within and outside the context of allo-HSCT, as well as the opportunities and challenges for developers and for payers.

Expression of RHAMM and WT1 As Well As T Cell Responses to These Antigens Before and After Allogeneic Stem Cell Transplantation in Patients with Leukemia

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4315-4315
Author(s):  
Rosaely Casalegno-Garduño ◽  
Claudia Meier ◽  
Jiju Mani ◽  
Kersten Borchert ◽  
Inken Hilgendorf ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Complete Remission ◽  
Stem Cell Transplantation ◽  
Mononuclear Cells ◽  
T Cell Responses ◽  
T Cell Response ◽  
Cell Responses ◽  
Before And After

Abstract Abstract 4315 Introduction: Patients with leukemia undergo chemotherapy as first treatment. Approximately 70–80% of patients with acute myeloid leukemia (AML) reach complete remission. However, most of them will relapse and only 25% survive more than five years. Therefore, there is a need for novel approaches in the treatment of leukemia, such as immunotherapy. Leukemic blasts have an aberrant expression of antigens. They are called leukemia-associated antigens (LAAs) like the receptor for hyaluronan acid-mediated motility (RHAMM) and the Wilms’ tumor gene 1 product (WT1). Epitopes of these LAAs can be recognized by CD8+ T cells. MATERIAL AND METHODS: In the present study, we analyzed the correlation between the clinical course of 18 patients suffering from leukemia (10 AML, 5 MDS, 1 ALL and 2 B-CLL) with the expression of RHAMM and WT1 transcripts before and after allogeneic stem cell transplantation (allo-SCT). Gene transcripts were measured by quantitative real time PCR (RQ-PCR) from RNA of peripheral blood mononuclear cells (PBMC) and bone marrow mononuclear cells (BMMC) samples. Antigen specific T cells were enriched in a mixed lymphocyte-peptide culture (MLPC) and antigen specific T cell responses were measured by enzyme-linked immunosorbent spot (ELISPOT). Results: We observed a reduction in WT1 transcripts in both PBMC and BMMC after transplantation in all of the WT1 positive patients (6/18 patients: 33%). Four of these six WT1+ patients (67%) remained in complete remission (CR) with low transcripts of WT1 (PBMC: lower than 14 WT1 copies/104 ABL copies, BMMC: lower than 202 WT1 copies/104 ABL copies). In contrast, 2 of 6 WT1+ patients (33%) showed an increase (PBMC: up to 98 WT1 copies/104 ABL copies, BMMC: up to 920 WT1 copies/104 ABL copies) of WT1 transcripts eventually resulting in a relapse. Specific T cell responses were detected against WT1 in two of three WT1+ patients in the presence of blasts (before transplantation or in relapse). However, these specific responses vanished while the patients reached a CR. Furthermore, RHAMM+ patients (12/18: 67%) showed different patterns when correlated with clinical status. Five patients (42%) showed gradually increased levels of RHAMM transcripts during CR. No RHAMM specific T cells could be detected in this group (2/2 MLPCs). Four patients (33%) showed a decrease in the transcripts of RHAMM when they reached a CR. One of these patients developed a T cell response to RHAMM three months after allo-SCT (2/2 MLPCs). One patient showed high transcripts of RHAMM and WT1 during the diagnosis, WT1 transcripts were reduced after allo-SCT. Both RHAMM and WT1 transcripts gradually increased until the patients died. We could detect in this patient both WT1 and RHAMM-specific T cells before transplantation. After allo-SCT the T cell response vanished. CONCLUSION: Taken together, WT1 is a suitable marker for minimal residual disease after allo-SCT. One might speculate that T cells specific for WT1 vanished during the CR due to the absence of the antigen to stimulate the proliferation of specific T cell population. Moreover, the presence of RHAMM-specific T cells may help to maintain a CR. In both cases vaccination with RHAMM and WT1 derived peptide might enhance T cell responses in the patient leading to a better outcome of the patient. Disclosures: Freund: Medac: Honoraria, Research Funding.

Efficient Generation of Tumor-Specific, Cytotoxic T Cells by Genetic Transfer of allo-MHC.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2755-2755
Author(s):  
Erlend Stronen ◽  
Ingerid Abrahamsen ◽  
Finn-Eirik Johansen ◽  
Gustav Gaudernack ◽  
Fridtjof Lund-Johansen ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Cell Lines ◽  
Mononuclear Cells ◽  
Cytotoxic T Cell ◽  
Target Cells ◽  
Melanoma Tumor ◽  
Peripheral Blood Mononuclear ◽  
Mhc Class I Molecule

Abstract Immune responses to established cancer are difficult to evoke by vaccination of patients due to various mechanisms of tolerance. In contrast, T cells in allogeneic stem cell grafts can contribute to cure of a number of hematological malignancies by the graft-versus-leukemia (GvL) effect. However, unknown T cell specificities causing life-threatening graft-versus-host disease (GvHD) limit the applicability of this treatment. Selection of GvL activity would increase the efficiency, safety and applicability of allogeneic stem cell transplantation. Here, we describe a novel method for overcoming tolerance by generation of allo-restricted, antigen-specific T cells. These cells specifically recognize and kill melanoma tumor cells presenting the melanoma-associated MART-1 in context of the prevalent major histocompatibility complex (MHC) class I molecule HLA-A*0201. HLA-A*0201-negative peripheral blood mononuclear cells were co-cultured with autologous, monocyte-derived dendritic cells transfected with HLA-A*0201 mRNA and subsequently pulsed with the peptide ELAGIGILTV from the melanoma-associated antigen MART-1. Antigen-specific T cells were detected in 8/10 donors on day 12 using peptide-MHC-pentamers (median 0.28% of CD8+ T cells, range 0-4.17%), and in all donors by day 19. When needed, cells were restimulated on day 12 with HLA-A*0201 mRNA-transfected and peptide pulsed autologous EBV-transformed lymphoblastoid cell lines (EBV-LCL). MART-1 pentamer+ T cells from five donors were sorted and expanded. The cytotoxic T cell lines (CTLs) responded with production of interferon-γ, degranulation and lysis of target cells when stimulated with peptide-pulsed EBV-LCL, even at low peptide concentrations (10−5 M). Similar responses were seen to melanoma cell lines expressing HLA-A*0201 and MART-1 (FM-57, Malme3M). In contrast, MART-1+ melanoma cells lacking HLA-A*0201 (Mel202) induced responses only when transfected with HLA-A*0201. Starting out with 0.5×106 pentamer+ T cells, a potential number of 3.0×109 pentamer+ T cells could be reached four weeks later, representing a 7800-fold expansion Our data show that allo-restricted T cells with high specificity for tumor-associated antigens can be rapidly generated, sorted and expanded to clinically applicable numbers. Figure Figure

An in-Vivo Model of T Cell-Mediated Rejection of Human Hematopoietic CD34+ Stem Cells Using NOD/SCID γnull (NOG) Mice.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 4474-4474
Author(s):  
Benedetta Nicolini ◽  
Dolores Mahmud ◽  
Nadim Mahmud ◽  
Giuseppina Nucifora ◽  
Damiano Rondelli
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Mouse Model ◽  
Hematopoietic Stem ◽  
Human Cd34 ◽  
Cell Engraftment ◽  
Cd34 Cells ◽  
Nog Mice

Abstract Abstract 4474 We have previously demonstrated that human CD34+ cells include subsets of antigen presenting cells capable of stimulating anti-stem cell T cell alloreactivity in-vitro. In this study we transplanted human CD34+ cells and allogeneic T cells in a NOD/SCID γnull (NOG) mouse model and evaluated the occurrence of stem cell rejection as well as xenogeneic graft-versus-host disease (GVHD) following the infusion of different doses of T cells. After sublethal irradiation NOG mice were cotransplanted with 2×105 CD34+ cells and HLA mismatched CD4+CD25- T cells at 1:0 (control), 1:2 or 1:10 CD34+ cell: T cell ratio (n=5-10 mice per group). Hematopoietic stem cell and T cell engraftment was assessed in the bone marrow and in the spleen 6 weeks following transplantation or earlier in case the animals died. Control mice transplanted with CD34+ cells alone showed a high level of stem cell engraftment (huCD45+ cells: 60±10%) in the bone marrow, encompassing CD19+ B cells (64±4%), CD34+ cells (18±1%), CD33+ myeloid cells (7±1%), CD14+ monocytes (3±1%), and no T cells within huCD45+ cells. In contrast, mice that were transplanted with CD34+ cells and 4×105 (1:2 ratio) or 2×106 (1:10 ratio) T cells had only 9±2% and 3±1% huCD45+ cells, respectively, in the bone marrow (p=0.01). Moreover, marrow samples of mice cotransplanted with CD34+ cells and T cells at 1:2 or 1:10 ratio included >98% huCD3+ T cells and no CD34+ cells. Spleen engraftment of huCD45+ cells was lower (25±8%) in control mice (1:0 ratio) as compared to 66±10% and 36±11% in 1:2 and 1:10 groups, respectively (p=0.05). As observed in the marrow, also the spleen of animals receiving CD34+ and T cells included >98% CD3+ T cells. Among the T cells, both in the marrow and in the spleen of mice in the 1:2 and 1:10 ratio groups, 60-70% were CD4+CD8- cells, 22-25% CD8+CD4- cells, 1-3% CD56+ cells, and 2-5% CD4+CD25+ cells. In mice receiving 4 ×105 T cells (1:2 ratio), on average 12±6% of the T cells in the bone marrow and spleen were CD4+CD8+. Only mice receiving 2×106 T cells (1:10 ratio) showed GVHD. This was demonstrated by fur changes, reduced survival (p=0.02) and weight loss (p=0.0001) compared to control mice or mice receiving a lower dose of T cells (1:2 ratio). The marrow engraftment of CD3+ cells with disappearance of CD34+ cells in mice receiving low doses of allogeneic T cells, in the absence of evident xenogeneic GVHD, suggests that NOG mouse model represents a useful tool to study human stem cell rejection. This model will be also utilized to investigate new strategies of immunosuppressive cell therapy applied to stem cell transplantation in an HLA mismatched setting. Disclosures: No relevant conflicts of interest to declare.

Stem Cell Factor (SCF) Improves Thymopoiesis After Experimental Hematopoietic Stem Cell Transplantation In Both a Murine BMT Model and In “human Immune system” (HIS) Mice, Receiving a Human Stem Cell Graft.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3725-3725
Author(s):  
Elwin J Rombouts ◽  
Evert-Jan Wils ◽  
Irene Van Mourik ◽  
Nicolas Legrand ◽  
Hergen Spits ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
T Cell ◽  
Mouse Model ◽  
Fetal Liver ◽  
Immune Competence ◽  
Cell Recovery ◽  
Post Transplantation ◽  
Hematopoietic Stem ◽  
Human Fetal Liver

Abstract Abstract 3725 Deficient thymopoiesis, due to epithelial injury by chemo- and/or radiotherapy, age-associated thymic involution and by graft-versus-host disease, is an important determinant of the impaired immune competence following allogeneic transplantation. Therefore, strategies to improve thymopoiesis are considered pivotal to improve T cell recovery and immune competence after transplantation. As SCF is a cytokine produced by thymic stroma and its receptor, c-kit, is expressed by the earliest thymocytes, we evaluated whether SCF administration would improve thymic recovery following stem cell transplantation in immuno-deficient mice receiving: (1) a T-cell depleted bone marrow (BM) graft of congenic mice, or (2) a CD34+CD38low-selected xenogenic hematopoietic stem cell (HSC) graft of human fetal liver origin (HIS) mice model). In the mouse-mouse model, 10–12 week old rag-1−/− mice were 3 Gy irradiated (137Cs -source) and received 2×105 T-cell depleted C57Bl/6 (CD45.1) congeneic bone marrow cells intravenously. Recipient mice received either PBS or recombinat rat SCF (Amgen, USA, 100μg/kg per injection) by subcutaneous injection 3 times a week from day 1 until the end of the experiment. In this model, SCF enhanced thymopoiesis and peripheral T-cell recovery. BM lymphoid progenitor recovery was not affected. Median thymic cellularity increased from 0.9 in PBS- to 266 × 104/thymus in SCF-treated mice (p=0.05), which increase was similarly distributed over the thymocyte subsets of double negative (DN), double positive (DP), and CD4+, CD8+ single positive thymocytes. Next, we assessed whether SCF-induced improved thymic recovery also translated into improved T-cell recovery in the periphery. Absolute numbers of donor-derived newly developed CD4+ and CD8+ T-cells were quantified in peripheral blood, spleen and lymph nodes at weeks 4 and 6 post-transplantation. T-cell numbers were low at 4 weeks after transplantation and did not differ between PBS or SCF treated animals. However, at 6 weeks T-cell numbers were significantly increased in spleen and lymph nodes of SCF treated animals (p<0.05). Next, we studied the effect of recombinant human (rh) SCF in our HIS mouse model. In short, newborn (days 3–7) Rag-2−/−gc−/− mice were 3.5 Gy irradiated and transplanted with 5–10 × 104 CD34+CD38low human fetal liver (FL) cells intra-hepatically. CD34+CD38low cells were isolated via a two step procedure. CD34+− FL cells were isolated using a CD34 human progenitor cell-isolation kit and further sorted as CD38low using a FACS Aria (BD biosciences). In HIS mice, PBS or rhSCF (Amgen, USA) 100μg/kg per injection) was administered intraperitoneally (i.p.) 3 times weekly as of day 14 following transplantation. Similar to the murine BMT model, a higher thymic cellularity was observed in SCF treated mice (Fig. 1) in the HIS model. DN and early DP thymocyte subsets were enhanced, albeit not significantly. In contrast, lateDP, CD4SP and CD8SP thymocyte subset recovery was significantly enhanced in thymi of SCF-treated HIS mice. As the HIS model remains a hybrid human–mouse system with limited cytokine cross reactivity and in which MHC-HLA mismatch compromises peripheral T-cell survival (Legrand et al J IMMUNOL 2009), the model did not allow us to study the effect of SCF on T-cells in the peripheral lymphoid organs. Figure 1: SCF improves thymic recovery following human SCT in an HIS mouse model. Newborn rag-2−/− γc−/− mice were 3.5 Gy irradiated and received 5–10 × 104 CD34+CD38low human fetal liver cells intra-hepatically and were treated with PBS or SCF. At indicated times post transplantation, thymi were harvested analyzed for the human thymocyte subsets: TN (CD3-CD4-CD8-), early DP (CD3- CD4+CD8+), late DP (CD3+CD4+CD8+), CD4SP and CD8SP (CD3+CD4-CD8+). Figure 1:. SCF improves thymic recovery following human SCT in an HIS mouse model. Newborn rag-2−/− γc−/− mice were 3.5 Gy irradiated and received 5–10 × 104 CD34+CD38low human fetal liver cells intra-hepatically and were treated with PBS or SCF. At indicated times post transplantation, thymi were harvested analyzed for the human thymocyte subsets: TN (CD3-CD4-CD8-), early DP (CD3- CD4+CD8+), late DP (CD3+CD4+CD8+), CD4SP and CD8SP (CD3+CD4-CD8+). Collectively, these results show that SCF may significantly improve post-transplant thymopoiesis after both experimental murine BMT and human fetal liver HSC transplantation in HIS mice. While peripheral T-cell recovery was significantly enhanced in the murine BMT model, it remains to be established whether improved human thymopoiesis will also translate into better peripheral T-cell recovery and enhanced immune competence towards opportunistic infections as well as a better recovery of regulatory T cells. These studies now set the stage for studying SCF, either alone or combined with other thymopoietic cytokines, in a larger pre-clinical animal model. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Targeting CD38 is lethal to Breg-like chronic lymphocytic leukemia cells and Tregs, but restores CD8+ T-cell responses

2020 ◽  
Vol 4 (10) ◽  
pp. 2143-2157 ◽  
Author(s):  
Alak Manna ◽  
Timothy Kellett ◽  
Sonikpreet Aulakh ◽  
Laura J. Lewis-Tuffin ◽  
Navnita Dutta ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Chronic Lymphocytic Leukemia ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Transforming Growth Factor ◽  
Ex Vivo ◽  
Xenograft Model ◽  
Lymphocytic Leukemia ◽  
Dependent Manner

Abstract Patients with chronic lymphocytic leukemia (CLL) are characterized by monoclonal expansion of CD5+CD23+CD27+CD19+κ/λ+ B lymphocytes and are clinically noted to have profound immune suppression. In these patients, it has been recently shown that a subset of B cells possesses regulatory functions and secretes high levels of interleukin 10 (IL-10). Our investigation identified that CLL cells with a CD19+CD24+CD38hi immunophenotype (B regulatory cell [Breg]–like CLL cells) produce high amounts of IL-10 and transforming growth factor β (TGF-β) and are capable of transforming naive T helper cells into CD4+CD25+FoxP3+ T regulatory cells (Tregs) in an IL-10/TGF-β-dependent manner. A strong correlation between the percentage of CD38+ CLL cells and Tregs was observed. CD38hi Tregs comprised more than 50% of Tregs in peripheral blood mononuclear cells (PBMCs) in patients with CLL. Anti-CD38 targeting agents resulted in lethality of both Breg-like CLL and Treg cells via apoptosis. Ex vivo, use of anti-CD38 monoclonal antibody (mAb) therapy was associated with a reduction in IL-10 and CLL patient-derived Tregs, but an increase in interferon-γ and proliferation of cytotoxic CD8+ T cells with an activated phenotype, which showed an improved ability to lyse patient-autologous CLL cells. Finally, effects of anti-CD38 mAb therapy were validated in a CLL–patient-derived xenograft model in vivo, which showed decreased percentage of Bregs, Tregs, and PD1+CD38hiCD8+ T cells, but increased Th17 and CD8+ T cells (vs vehicle). Altogether, our results demonstrate that targeting CD38 in CLL can modulate the tumor microenvironment; skewing T-cell populations from an immunosuppressive to immune-reactive milieu, thus promoting immune reconstitution for enhanced anti-CLL response.

Class I–unrestricted noncytotoxic anti–HTLV-I activity of CD8+ T cells

Blood ◽  
2000 ◽  
Vol 96 (5) ◽  
pp. 1994-1995 ◽  
Author(s):  
Masako Moriuchi ◽  
Hiroyuki Moriuchi
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Mononuclear Cells ◽  
Membrane Filter ◽  
Cd8 T Cell ◽  
Class I ◽  
Type I ◽  
Peripheral Blood Mononuclear ◽  
Permeable Membrane

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.

scholarly journals The Worm-Specific Immune Response in Multiple Sclerosis Patients Receiving Controlled Trichuris suis Ova Immunotherapy

Life ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 101
Author(s):  
Ivet A. Yordanova ◽  
Friederike Ebner ◽  
Axel Ronald Schulz ◽  
Svenja Steinfelder ◽  
Berit Rosche ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
Clinical Efficacy ◽  
Mononuclear Cells ◽  
Phase 1 ◽  
Th2 Cells ◽  
Continuous Increase ◽  
Trichuris Suis ◽  
Multiple Sclerosis Patients

Considering their potent immunomodulatory properties, therapeutic applications of Trichuris suis ova (TSO) are studied as potential alternative treatment of autoimmune disorders like multiple sclerosis (MS), rheumatoid arthritis (RA), or inflammatory bowel disease (IBD). Clinical phase 1 and 2 studies have demonstrated TSO treatment to be safe and well tolerated in MS patients, however, they reported only modest clinical efficacy. We therefore addressed the cellular and humoral immune responses directed against parasite antigens in individual MS patients receiving controlled TSO treatment (2500 TSO p.o. every 2 weeks for 12 month). Peripheral blood mononuclear cells (PBMC) of MS patients treated with TSO (n = 5) or placebo (n = 6) were analyzed. A continuous increase of serum IgG and IgE antibodies specific for T. suis excretory/secretory antigens was observed up to 12 months post-treatment. This was consistent with mass cytometry analysis identifying an increase of activated HLA-DRhigh plasmablast frequencies in TSO-treated patients. While stable and comparable frequencies of total CD4+ and CD8+ T cells were detected in placebo and TSO-treated patients over time, we observed an increase of activated HLA-DR+CD4+ T cells in TSO-treated patients only. Frequencies of Gata3+ Th2 cells and Th1/Th2 ratios remained stable during TSO treatment, while Foxp3+ Treg frequencies varied greatly between individuals. Using a T. suis antigen-specific T cell expansion assay, we also detected patient-to-patient variation of antigen-specific T cell recall responses and cytokine production. In summary, MS patients receiving TSO treatment established a T. suis-specific T- and B-cell response, however, with varying degrees of T cell responses and cellular functionality across individuals, which might account for the overall miscellaneous clinical efficacy in the studied patients.

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