Immune Responses Against the Tumor-Associated Antigens WT1, MUC-1, PRAME and HER2/Neu in 114 Prospectively Screened Healthy Donors: Effects of Gender and Prior Pregnancy and Implications for Immunotherapy

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 4115-4115 ◽  
Author(s):  
Mathias Lutz ◽  
Andrea Worschech ◽  
Sabine Gahn ◽  
Laura Bernhard ◽  
Michael Schwab ◽  
...  
Keyword(s):  
T Cells ◽  
Healthy Volunteer ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
High Avidity ◽  
Tumor Associated Antigens ◽  
Healthy Donors ◽  
Significant Difference ◽  
Ifn Γ

Abstract Abstract 4115 Background: The graft-versus-leukemia (GvL) effect is a central component of the stem cell allograft's ability to cure hematological malignancies. While it has become evident that donor-derived T lymphocytes targeting tumor-associated antigens (TAAs) contribute significantly to the GvL effect little is known about the frequency and the origin of TAA-directed immune responses in healthy donors. Here we investigate for the first time their frequency against three well-known and transplant-relevant TAAs (WT1, MUC-1, PRAME) and one well-described TAA in solid tumor immunotherapy (HER2/neu) in a prospective manner considering gender and former pregnancy as potential influencing factors. Material and Methods: To detect the very low frequencies of these antigen-specific CD8+ T cells we have used immunodominant peptides of WT1, MUC-1, PRAME and HER2/neu and a quantitative polymerase chain reaction (qPCR) to measure Interferon-gamma (IFN-γ) mRNA production by peptide-pulsed CD8+ T cells from HLA-A*0201-positive healthy volunteers. After obtaining approval by the local ethical committee and written informed consent 114 HLA-A*0201-positive healthy volunteer blood donors were enrolled in this prospective research study including males (median age 40.5 years), nulliparous women (median age 27.5 years) and women with at least one delivery (median age 45.5 years). Each group consisted of 38 individuals as planned in the original study design. Peripheral blood was drawn, peripheral blood mononuclear cells (PBMCs) and CD8+ lymphocytes isolated and stimulated with peptide-loaded (0.1 and 10 μM), irradiated T2 cells. IFN-γ mRNA expression was measured by qPCR. The irrelevant melanoma antigen gp100 was used as a negative control and a stimulation index was calculated accordingly. A two-fold change or more as compared to gp100 was considered a positive result. The polyclonal stimulator PMA and a HLA-A*0201 restricted CMV peptide were used as positive controls. Results: Of the screened 114 healthy volunteer donors 17 (15%) showed immune responses against WT1, 8 (7%) against PRAME, 16 (14%) against MUC-1 and 6 (5%) against HER2/neu with one or both peptide concentrations. Comparing nulli- and multiparous women there was no significant difference regarding the frequency of assessed positive immune responses. However, comparing female (n=76) and male donors (n=36) we found that positive immune responses were more frequently present in men. Using the Mann-Whitney test this difference between men and women was significant for HER2/neu (p=0.0478) and reached borderline significance for PRAME (p=0.0677). This data is presented in Figure 1. Conclusions: In this prospectively screened cohort of healthy volunteer donors we could detect positive responses against WT1, MUC-1, PRAME and HER2/neu containing both low and high avidity immune responses. Prior delivery did not increase the frequency of immune responses. Interestingly, men showed a general tendency towards higher frequencies of immune responses to TAAs, particularly to HER2/neu and PRAME. Thus, the exploitation of donor-derived autoimmunity against selected TAAs by improving donor selection and facilitating adoptive immunotransfer of donor-derived T cells may significantly contribute to the control of the malignant disease after allotransplantation. Disclosures: No relevant conflicts of interest to declare.

HLA-A*0201 Restricted Killing Activity of WT1-Specific CTL Generated From the Peripheral Blood Lymphocytes of Normal Healthy Donors.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3026-3026
Author(s):  
Deepa Kolaseri Krishnadas ◽  
Mindy Stamer ◽  
Kim Dunham ◽  
Lei Bao ◽  
Kenneth Lucas
Keyword(s):  
T Cells ◽  
Cell Line ◽  
Cd8 T Cells ◽  
Peripheral Blood ◽  
Peripheral Blood Lymphocytes ◽  
Target Cells ◽  
Cd8 Cells ◽  
Blood Lymphocytes ◽  
Healthy Donors ◽  
Ifn Γ

Abstract Abstract 3026 Poster Board II-1002 The Wilms' tumor antigen (WT1) is over-expressed on several human leukemia and solid tumors, and thus is considered as a potential target for cancer immunotherapy. Combating leukemia by targeting WT1 expressing leukemic cells using in vitro generated WT1-specific CTL is one potential approach, but it is difficult to generate an immune response against WT1 due to low T cell precursor frequency in normal healthy individuals. Earlier studies have shown the generation of WT1-A*0201 peptide specific CTL from CD8+ T cells by cloning. Another study reported the production of IFN- γ by WT-1 specific CD8+ T cells. However, the cytolytic killing ability of these IFN- γ producing cells was not further characterized. Here, we demonstrate the generation of WT1-A*0201 specific CTL from the peripheral blood lymphocytes (PBL) of normal healthy donors using CD137 selection. The PBL were stimulated once with RMFPNAPYL (WT1-A*0201 peptide) pulsed autologous dendritic cells and twice with WT1-A*0201 peptide pulsed irradiated peripheral blood mononuclear cells (PBMC). Following three stimulations, the PBL were selected for CD137+ expression and rapidly expanded with OKT3 and IL-2. The WT1-A*0201 specific CTL showed killing of target cells and production of IFN-γ in an antigen-specific manner. The percent killing of WT1-A*0201 peptide pulsed T2 cells (TAP−, HLA- A2+) and autologous B blast (BB) were significantly higher when compared with their control targets. T2 cells and BB either pulsed with an irrelevant A*0201 peptide or un-pulsed served as the control. We have observed similar results with WT1-A*0201 specific CTL generated from normal donor CD8+ cells. However, the efficiency of WT1-A*0201 CTL generated from PBL to kill target cells and produce IFN- γ was higher than CTL from CD8+ cells. The CTL generated from PBL killed BA25, a WT1 expressing A2+ leukemia cell line but failed to kill Molt-4, a WT1 expressing A2− cell line, clearly indicating HLA-A2 restricted CTL activity. The specificity of the generated CTL were further confirmed by staining with WT1-HLA-A*0201 tetramer. The percentage of WT1-specific CD3+CD8+Tetramer+ cells either remained same or higher in CTL generated from PBL when compared with those generated from CD8+ cells. CD137 selection leads to the generation of significant number of CTL in a shorter time when compared to conventional cloning methods. In addition, generation of WT1-A*0201 specific CTL from PBL avoids CD8+ selection. Currently, we are aiming to generate WT1-specific CTL using an overlapping WT1 peptide-mix in order to widen our ability to treat patients with different HLA types. This study has implications for cellular immunotherapy in leukemia patients who relapse following allogeneic stem cell transplantation. Disclosures No relevant conflicts of interest to declare.

Clinical Grade Generation of T-Helper-1-Driven Polyclonal T-Cell Populations for Adoptive Immunotherapy Against Tumor Associated Antigens

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4314-4314
Author(s):  
Simone Kayser ◽  
Cristina Boß ◽  
Vanya Icheva ◽  
Stefan Stevanovic ◽  
Peter Lang ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cell Therapy ◽  
Peripheral Blood ◽  
Adoptive T Cell Therapy ◽  
T Helper ◽  
T Cell Therapy ◽  
Tumor Associated Antigens ◽  
Healthy Donors ◽  
Ifn Γ

Abstract Abstract 4314 Adoptive T cell therapy has been shown an option to treat patients with malignancies. In contrast to vaccinations, T cells for adoptive T-cell therapy are generated ex vivo to be re-infused into the recipient. This enables treatment of immunocompromized hosts and use of allogeneic T cells to exploit graft versus tumor effects. Adoptive T-cell therapy involving CD4+ T-helper cells (Th cells), intends to induce sustained T-cell responses in vivo. The Th1 cytokine interferon-gamma (IFN-γ) has not only an effect in orchestrating cytotoxic T-cell reponses, IFN-γ by itself has antitumor effects. Transferring T cells in a lymphopenic host furthermore eliminates regulatory T cells (Tregs) and offers access to homeostatic cytokines. The aim of our study was the translation of preclinical data into a GMP conform clinical scale protocol to generate specific T cells for adoptive T-cell therapy against tumor associated antigens. Large scale generations of NY-ESO-1 specific T cells was performed according to current GMP regulations in a GMP facility. In brief, peripheral blood mononuclear cells from healthy donors were primed with an overlapping NY-ESO-1 15-mer peptide mix. The priming was done in the presence of IL-7 and IL-2. T cells were enriched using IFN-γ capture technique and expanded for two weeks in autologous culture conditions with IL-7, IL-15 and IL-2. T-cell specificity, function and proliferation capacity was analyzed by flow cytometry. The T-cell products showed high numbers of specifically IFN-γ+, TNF-alpha+ T cells. Tolerance inducing cytokines like IL-10 were absent. Enrichment of Tregs was excluded. Both, CD4+ and CD8+ T cells with an effector memory phenotype proliferated in response to NY-ESO-1. CD107a assays demonstrated cytotoxic capacities of T cells. The T-cell product did not include alloreactive T cells. In summary GMP-conform generation of NY-ESO-1 specific T cells was established. Although tumor associated antigens are potential self antigens, it is possible to induce a functional Th1 response in peripheral blood T cells from healthy donors. Adoptive T-cell therapy against tumor associated antigens could have implications for multiple tumor entities in autologous as well as allogeneic treatment approaches. Disclosures: No relevant conflicts of interest to declare.

scholarly journals The effect of Kefir on The Immune Response of Healthy Volunteers In Vitro

2017 ◽  
Vol 3 (2) ◽  
pp. 28
Author(s):  
Desie Dwi Wisudanti
Keyword(s):  
Immune Response ◽  
T Cells ◽  
Immune Responses ◽  
Healthy Volunteers ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Fermented Milk ◽  
Bioactive Components ◽  
Ifn Γ

Kefir is a functional foodstuff of probiotics, made from fermented milk with kefir grains containing various types of beneficial bacteria and yeast. There have been many studies on the effects of oral kefir on the immune system, but few studies have shown the effect of bioactive components from kefir (peptides and exopolysaccharides/ kefiran), on immune responses. The purpose of this study was to prove the effect of kefir supernatant from milk goat on healthy immune volunteer response in vitro. The study was conducted on 15 healthy volunteers, then isolated PBMC from whole blood, then divided into 5 groups (K-, P1, P2, P3 and P4) before culture was done for 4 days. The harvested cells from culture were examined for the percentage of CD4+ T cells, CD8+ T cells, IFN-γ, IL-4 using flowsitometry and IL-2 levels, IL-10 using the ELISA method. The results obtained that kefir do not affect the percentage of CD4+ T cells and CD8+ T cells. The higher the concentration of kefir given, the higher levels of secreted IFN- γ and IL-4, but a decrease in IL-2 levels. Significant enhancement occurred at levels of IL-10 culture PBMC given kefir with various concentrations (p <0.01), especially at concentrations of 1%. These results also show the important effects of kefir bioactive components on immune responses. The conclusion of this study is that kefir can improve the immune response, through stimulation of IL-10 secretion in vitro.

Identification of the AAV2 Capsid CD8+ T Cell Epitope in C57BL/6 Mice.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3188-3188
Author(s):  
Denise E. Sabatino ◽  
Federico Mingozzi ◽  
Haifeng Chen ◽  
Peter Colosi ◽  
Hildegund C.J. Ertl ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Capsid Protein ◽  
Cd8 T Cells ◽  
Cell Epitope ◽  
T Cell Response ◽  
Cd8 Cells ◽  
Media Control ◽  
Ifn Γ

Abstract Recently, a clinical trial for adeno-associated virus serotype 2 (AAV2) mediated liver directed gene transfer of human Factor IX to subjects with severe hemophilia B revealed that two patients developed transient asymptomatic transaminitis following vector administration. Immunology studies in the second patient demonstrated a transient T cell response to AAV2 capsid peptides suggesting that the immune response to the AAV capsid may be related to the transient transaminitis. We hypothesized that the observations made in the human subjects were due to a CD8 T cell response to AAV2 capsid protein. Preclinical studies in mice and dogs, which are not naturally infected by wild type AAV2 viruses, did not predict these findings in the clinical study. Thus, we developed a mouse model in which we were able to mimic this phenomenon (Blood 102:493a). In an effort to further characterize the immune responses to AAV2 capsid proteins in this mouse model, we identified the T cell epitope in the AAV capsid protein recognized by murine C57Bl/6 CD8 T cells. A peptide library of AAV2 VP1 capsid peptides (n=145) that were synthesized as 15mers overlapping by 10 amino acids were divided into 6 pools each containing 24–25 peptides. C57Bl/6 mice were immunized intramuscularly with an adenovirus expressing AAV2 capsid protein. Nine days later the spleen was harvested and intracellular cytokine staining (ICS) was used to assess release of IFN-γ from CD8 T cells in response to 6 AAV2 capsid peptide pools. ICS demonstrated CD8 cells from mice immunized with Ad-AAV2 produced IFN-γ (3.5% of the CD8 cells) in response to Pool F (amino acid 119–145) while no IFN-γ release in CD8 cells was detected with Pool A to E (mean 0.28%±0.25%) compared to the media control (0.16%). This detection of IFN-γ release from CD8 T cells indicates a specific proliferation to a peptide(s) within this peptide pool (Pool F). A matrix approach was used to further define which peptide(s) contained the immunodominant epitope. Eleven small peptide pools of Pool F were created in which each peptide was represented in 2 pools. ICS of splenocytes from immunized (Ad-AAV2 capsid) C57Bl/6 mice demonstrated IFN-γ response from CD8 cells to 3 of the matrix pools corresponding to peptide 140 (PEIQYTSNYNKSVNV) and 141 (TSNYNKSVNVDFTVD) compared with media controls. To determine the exact peptide sequence that binds to the MHC Class I molecule, 9 amino acid peptides (n=7) were created that overlap peptide 140 and 141. Peptide SNYNKSVNV showed positive staining for both CD8 and IFN- γ(3.2%) compared with the six other peptides (0.14%±0.08%), media control (0.08%) and mice that were not immunized (0.11%). This epitope lies in the C terminus of the AAV2 VP1 capsid protein. Current studies using strains of mice with different MHC H2 haplotypes will allow us to determine which of the C57Bl/6 MHC alleles the epitope binds. These findings will provide us with a powerful tool for assessing immune responses to AAV capsid in the context of gene therapy. Specifically, they will allow us to determine how long immunologically detectable capsid sequences persist in an animal injected with AAV vectors. This in turn will provide a basis for a clinical study in which subjects are transiently immunosuppressed, from the time of vector injection until capsid epitopes are no longer detectable by the immune system.

Donor DC Subsets Polarize Donor T-Cell Immune Responses in Allogeneic BMT.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 573-573
Author(s):  
Jian-Ming Li ◽  
Cynthia Giver ◽  
Doug McMillan ◽  
Wayne Harris ◽  
David L. Jaye ◽  
...  
Keyword(s):  
Stem Cells ◽  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Peripheral Blood ◽  
Immune Reconstitution ◽  
Hematopoietic Cell ◽  
Post Transplant ◽  
Donor T Cells ◽  
Ifn Γ

Abstract Introduction: Impaired or inappropriate immune reconstitution after allogeneic bone marrow transplantation (BMT) can lead to infection, graft-versus-host disease (GvHD) and leukemia relapse. We have previously reported that BM contains two populations of dendritic cell (DC) subsets, CD11b+ DC and CD11b− DC, and that CD11b depleted donor BM promoted increased donor T-cell chimerism and increased graft-versus-leukemia (GvL) activity in C57BL/6 → B10BR transplants [BBMT, 2004, 10: 540]. To explore the mechanism by which CD11b-depletion improved allo-reactivity, we performed allogeneic hematopoietic cell transplants using defined populations of donor stem cells, DCs, and T-cells in a MHC mis-matched BMT model. Methods: We transplanted FACS purified populations of 50,000 GFP+ CD11b- DC or CD11b+ DC in combination with 5,000 FACS purified Lin- Sca-1+ c-kit+ hematopoietic stem cells (HSC) and 300,000 or 1,000,000 congenic spleen T-cells from C57BL/6 donors into C57BL/6[H-2Kb], B10BR[H-2Kk] and PL/J[H-2Ku] recipients. Proliferation of CFSE stained donor T-cells was measured at 72 hours post-transplant. FACS cytometric bead array and intracellular cytokine staining measured serum and intracellular cytokines in donor T-cells. Results: The initial proliferation and Ki-67 expression of CFSE labeled donor T-cells in allogeneic recipients were much higher than in syngeneic recipients (homeostatic proliferation). Confocal microscopy showed co-localization of donor DC subsets with donor T-cells in the recipient spleens at 3 and 10 days post-transplant. In the allogeneic transplant settings, donor T-cells co-transplanted with CD11b- DC showed increased IFN-γ synthesis at 3 and 10 days post-transplant compared to donor T-cells co-transplanted with HSC plus CD11b+ DC or HSC alone. Increased proliferation of donor T-cells led to increased donor T-cell chimerism at day 10, 30, 60, and day105 post-transplant among recipients of CD11b- DC compared to recipients of HSC alone or HSC plus CD11b+ DC (Figure 1). Transplantation of spleen T-cells and CD11b- DC did not increase GvHD, but was associated with full donor chimerism. In contrast, transplantation of allogeneic CD11b+ DC led to persistence and expansion of residual host T-cells (Figure 2), increased numbers of donor CD4+CD25++Foxp3+ T-cells, and higher serum level of IL-10 supporting early post-transplant expansion of donor T regulatory cells (Treg). Conclusions: Donor CD11b- DC promoted immune reconstitution by polarizing donor T-cells to Th1 immune responses associated with increased IFN-γ synthesis and donor T-cell proliferation, while donor CD11b+ DC suppressed immune reconstitution by inhibiting donor T-cell allogeneic immune responses. These data support a novel paradigm for the regulation of post-transplant immunity and suggest clinical methods to test the hypothesis that manipulation of the DC content of a hematopoietic cell allograft regulates post transplant immunity in the clinical setting. Figure 1. Donor Spleen Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(+)DC and spleen T-cells] Figure 1. Donor Spleen Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(+)DC and spleen T-cells] Figure 2. Host Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(-)DC and spleen T-cells] Figure 2. Host Derived T-cells in Peripheral Blood [* p<0.05, v.s. recipients of HSC plus CD11b(-)DC and spleen T-cells]

Ex-Vivo Characterization of Polyclonal Memory CD8+ T-Cell Responses to PRAME-Specific Peptides in Patients with Acute Leukemia and Chronic Myeloid Leukemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2910-2910
Author(s):  
Katayoun Rezvani ◽  
Agnes S. M. Yong ◽  
Abdul Tawab ◽  
Behnam Jafarpour ◽  
Rhoda Eniafe ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Myeloid Leukemia ◽  
Ex Vivo ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
High Avidity ◽  
Cell Responses ◽  
Ifn Γ

Abstract PRAME (Preferentially expressed antigen of melanoma) is aberrantly expressed in hematological malignancies and may be a useful target for immunotherapy in leukemia. We studied CD8+ T-cell responses to four HLA-A*0201-restricted PRAME-derived epitopes (PRA100, PRA142, PRA300, PRA425) in HLA-A*0201-positive patients with acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and healthy donors, using PRA300/HLA-A*0201 tetramer staining, intracellular cytokine (IC) assay and ex-vivo and cultured ELISPOT analysis. CD8+ T-cells recognizing PRAME peptides were detected directly ex-vivo in 4/10 ALL, 6/10 AML, 3/10 CML patients and 3/10 donors. The frequency of PRAME-specific CD8+ T-cells was greater in patients with AML, CML and ALL than in healthy controls. All peptides were immunogenic in patients, whilst PRA300 was the only immunogenic peptide in donors. High PRAME expression in patient peripheral blood mononuclear cells was associated with responses to two or more PRAME epitopes (4/7 vs. 0/23 in individuals with low PRAME expression, P = 0.001), suggesting a PRAME-driven T-cell response. In 2 patients studied PRA300/HLA-A*0201+ CD8+T-cells were found to be a mixture of effector and central memory phenotypes. To determine the functional avidity of the PRAME T-cell response, the response of CD8+ T-cells to stimulation with 2 concentrations of peptide was measured by IC-IFN-γ staining. High-avidity CD8+ T-cells were defined as those capable of producing IFN-γ in response to the lower concentration of peptide (0.1μM), while low-avidity CD8+ T-cells were those that only produced IFN-γ in response to the higher concentration of peptide (10 μM). Both high and low-avidity CD8+ T-cell responses could be detected for all peptides tested (median 1.05, 0.90, 0.52, 0.40 high/lowavidity ratios for PRA100, PRA142, PRA300 and PRA425 respectively). In patients with high PRAME expression (&gt;0.001 PRAME/ABL) low-avidity CD8+ T-cell responses to PRAME peptides were more prominent than high-avidity responses, suggesting selective deletion of high-avidity T-cells. In contrast, in some patients with levels &lt;0.001 PRAME/ABL, we could detect the presence of high-avidity CD8+ T-cell responses to PRAME. PRAME-specific CD8+ T-cells were further characterized by IC staining for IL-2, IL-4 and IL-10 production and CD107a mobilization (as a marker of cytotoxicity). Following stimulation with the relevant PRAME peptide, there was no significant production of IL-2, IL-4 or IL-10, suggesting a Tc1 effector response but no significant CD107a mobilization was detected despite significant CD107a mobilization in the same patient in response to CMVpp65495. This finding suggests that patients with leukemia have a selective functional impairment of PRAME-specific CD8+ T-cells, consistent with PRAME-specific T cell exhaustion. However, PRAME-specific T-cells were readily expanded in the presence of cytokines in short-term cultures in-vitro to produce IFN-γ, suggesting that it may be possible to improve the functional capacity of PRAME-specific T-cells for therapeutic purposes. These results provide evidence for spontaneous T-cell reactivity against multiple epitopes of PRAME in ALL, AML and CML and support the usefulness of PRAME as a target for immunotherapy in leukemia. The predominance of low-avidity PRAME-specific CD8+ T-cells suggests that achievement of a state of minimal residual disease may be required prior to peptide vaccination to augment T-cell immune surveillance.

Phagocytosis May Be a Regulatory Mechanism for Myeloid Dendritic Cells to Terminate Type 1 CD8+ T Cells.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1654-1654
Author(s):  
Young-June Kim ◽  
Hal E. Broxmeyer
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Phagocytic Activity ◽  
Regulatory Mechanism ◽  
Gm Csf ◽  
T Cell Immune Responses ◽  
Ifn Γ

Abstract Abstract 1654 Poster Board I-680 CD8+ cytotoxic T cells are often ‘exhausted’ by programmed death-1 (PD-1) signaling, and subsequently the functions of these cells are terminated especially in a tumor environment or upon chronic HIV or HCV infection. Subsets of myeloid cells referred to as myeloid derived suppressor cells (MDSC) or regulatory dendritic cells (DCs) have been implicated in inducing exhaustion or termination of effector CD8+ T cells. To this end, we developed various myeloid-derived dendritic cell (DC) types in vitro from human CD14+ monocytes using M-CSF or GM-CSF in the presence of IL-4 with/without other cytokines, and characterized these DCs with respect to their capacity to induce PD-1 expression on and exhaustion of CD8+ T cells. We then assessed their impact on longevity of CD8+ T cells following coculture. Myeloid DCs developed in vitro with M-CSF and IL-4 for 5 days (referred to as M-DC) did not express ligand for PD-1 (PD-L1) nor did they induce PD-1 on CD8+ T cells. Thus, using M-DCs as starting cells, we sought determinant factors that could modulate M-DCs to express PD-L1 and thereby induce exhaustion of CD8+ T cells. In order to better monitor exhaustion processes, we incubated human peripheral CD8+ T cells for 5 days in the presence of IL-15, an important cytokine for maintaining viability, before coculture. M-DCs showed little impact on exhaustion or longevity of the CD8+ T cells. IL-10 converted M-DC into a distinct myeloid DC subset (referred to as M-DC/IL-10) with an ability to express PD-L1 as well as to induce PD-1 on cocultured CD8+ T cells. M-DC/IL-10 cells markedly suppressed proliferation of cocultured CD8+ T cells. M-DC/IL-10 cells were morphologically unique with many granules and filamentous structures around the cell periphery. These IL-10 effects on M-DC were completely abrogated in the presence of TNF-á. M-DC/IL-10 cells could be further differentiated into another myeloid DC subset in the presence of IFN-γ (referred to as M-DC/IL-10/IFN-γ) with an ability to express even higher levels of PD-L1 compared to M-DC/IL-10 cells. The most remarkable effect of M-DC/IL-10/IFN-γ cells on cocultured CD8+ T cells was a dramatic loss of CD8+ T cells. Light and confocal microscopic observations indicated that loss of CD8+ T cells was due to phagocytosis by M-DC/IL-10/IFN-γ cells. As IFN-γ, a type 1 cytokine which is induced in CD8+ T cells by IL-12 is essential for phagocytosis, we tested whether IL-12 treatment of CD8+ T cells could further enhance phagocytosis induced by M-DC/IL-10/IFN-γ cells. Indeed, IL-12 treatment greatly increased numbers of phagocytosed CD8+ T cells. In contrast, IL-4 treated CD8+ T cells became resistant to phagocytosis, suggesting IFN-γ producing (type1) CD8+ T cells may be primary target cells for the M-DC/IL-10 cells mediated phagocytosis. CD4+ T cells were not as susceptible as CD8+ T cells to phagocytosis. We failed to detect such phagocytic activity induced by prototype DCs generated with GM-CSF and IL-4. Phagocytic activity was not inhibited by various arginase-1 inhibitors suggesting that nitric oxide signaling may not mediate phagocytic activity. Neutralizing antibody to PD-L1 slightly but significantly lowered phagocytic activity suggesting that PD-L1/PD-1 interaction may be partially involved in this process. Myeloid DCs are thought to be immunogenic, actively inducing T cell immune responses. Our results demonstrate that myeloid DCs may play suppressive roles as well through induction of phagocytic activity, especially against IFN-γ producing CD8+ T cells. This may serve as a regulatory mechanism for type 1 CD8+ T cell immune responses in an IL-10 enriched microenvironment. Disclosures No relevant conflicts of interest to declare.

scholarly journals Differential Roles of Interleukin 15 mRNA Isoforms Generated by Alternative Splicing in Immune Responses in Vivo

2000 ◽  
Vol 191 (1) ◽  
pp. 157-170 ◽  
Author(s):  
Hitoshi Nishimura ◽  
Toshiki Yajima ◽  
Yoshikazu Naiki ◽  
Hironaka Tsunobuchi ◽  
Masayuki Umemura ◽  
...  
Keyword(s):  
T Cells ◽  
Alternative Splicing ◽  
Transgenic Mice ◽  
Immune Responses ◽  
Cd8 T Cells ◽  
Salmonella Infection ◽  
Mrna Isoforms ◽  
Interleukin 15 ◽  
Ifn Γ

At least two types of interleukin (IL)-15 mRNA isoforms are generated by alternative splicing at the 5′ upstream of exon 5 in mice. To elucidate the potential roles of IL-15 isoforms in immune responses in vivo, we constructed two groups of transgenic mice using originally described IL-15 cDNA with a normal exon 5 (normal IL-15 transgenic [Tg] mice) and IL-15 cDNA with an alternative exon 5 (alternative IL-15 Tg mice) under the control of an MHC class I promoter. Normal IL-15 Tg mice constitutionally produced a significant level of IL-15 protein and had markedly increased numbers of memory type (CD44high Ly6C+) of CD8+ T cells in the LN. These mice showed resistance to Salmonella infection accompanied by the enhanced interferon (IFN)-γ production, but depletion of CD8+ T cells exaggerated the bacterial growth, suggesting that the IL-15–dependent CD8+ T cells with a memory phenotype may serve to protect against Salmonella infection in normal IL-15 Tg mice. On the other hand, a large amount of intracellular IL-15 protein was detected but hardly secreted extracellularly in alternative IL-15 Tg mice. Although most of the T cells developed normally in the alternative IL-15 Tg mice, they showed impaired IFN-γ production upon TCR engagement. The alternative IL-15 transgenic mice were susceptible to Salmonella accompanied by impaired production of endogenous IL-15 and IFN-γ. Thus, two groups of IL-15 Tg mice may provide information concerning the different roles of IL-15 isoforms in the immune system in vivo.

Functional leukemia-associated antigen-specific memory CD8+ T cells exist in healthy individuals and in patients with chronic myelogenous leukemia before and after stem cell transplantation

Blood ◽  
2003 ◽  
Vol 102 (8) ◽  
pp. 2892-2900 ◽  
Author(s):  
Katayoun Rezvani ◽  
Matthias Grube ◽  
Jason M. Brenchley ◽  
Giuseppe Sconocchia ◽  
Hiroshi Fujiwara ◽  
...  
Keyword(s):  
T Cells ◽  
Stem Cell ◽  
Stem Cell Transplantation ◽  
Cell Transplantation ◽  
Cd8 T Cells ◽  
Healthy Individuals ◽  
Low Frequencies ◽  
Healthy Donors ◽  
Before And After ◽  
Ifn Γ

Abstract Antigens implicated in the graft-versus-leukemia (GVL) effect in chronic myeloid leukemia (CML) include WT1, PR1, and BCR-ABL. To detect very low frequencies of these antigen-specific CD8+ T cells, we used quantitative polymerase chain reaction (qPCR) to measure interferon-γ (IFN-γ) mRNA production by peptide-pulsed CD8+ T cells from HLA-A*0201+ healthy volunteers and from patients with CML before and after allogeneic stem cell transplantation (SCT). Parallel assays using cytomegalovirus (CMV) pp65 tetramers demonstrated the IFN-γ copy number to be linearly related to the frequency of tetramer-binding T cells, sensitive to frequencies of 1 responding CD8+ T cell/100 000 CD8+ T cells. Responses to WT1 and PR1 but not BCR-ABL were detected in 10 of 18 healthy donors. Responses to WT1, PR1, or BCR-ABL were observed in 9 of 14 patients with CML before SCT and 5 of 6 after SCT, often to multiple epitopes. Responses were higher in patients with CML compared with healthy donors and highest after SCT. These antigen-specific CD8+ T cells comprised central memory (CD45RO+CD27+CD57–) and effector memory (CD45RO–CD27–CD57+) T cells. In conclusion, leukemia-reactive CD8+ T cells derive from memory T cells and occur at low frequencies in healthy individuals and at higher frequencies in patients with CML. The increased response in patients after SCT suggests a quantitative explanation for the greater effect of allogeneic SCT.

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