Functional T Cell Array Reveals Pre-Treatment Expanded Terminal Effector Memory Response Is Associated with Lenalidomide Failure in Non-Del(5q) Myelodysplastic Syndrome.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1759-1759
Author(s):  
P.K. Epling-Burnette ◽  
JianXiang Zou ◽  
Jeffrey S. Painter ◽  
Dung-Tsa Chen ◽  
Jimmy Fulp ◽  
...  

Abstract Abstract 1759 Poster Board I-785 Lenalidomide (LEN) is a thalidomide derivative with proven efficacy for the treatment of patients with myelodysplastic syndrome (MDS). High rates of erythroid and cytogenetic response in patients with chromosome 5q deletion [del(5q)] produced the first FDA-approved karyotype-specific treatment for this disease. Transfusion-independence rates of approximately 25% have been reported previously for patients with non-[del(5q)] and efficacy in this population has been linked to the promotion of erythroid differentiation. Because impaired erythroid differentiation in lower-risk MDS may occur through several pathophysiological mechanisms, the identification of additional factors with predictive value for both response and failure to LEN are needed to optimize success of treatment. In addition to affecting erythroid differentiation, LEN has well-known potential for immune modulation and generates highly potent effector T cell responses in vitro and in vivo by potentiating T cell receptor signaling. Immune deregulation mediated by autoreactive effector T cells has been linked to impaired erythropoiesis and granulopoiesis in a distinct subset of MDS patients raising the question of whether LEN impacts the disease process in this subset of patients. To understand the relationship between T cell deregulation and LEN response, we conducted a pilot study of 13 low/INT-1-risk non-del (5q) MDS patients (7 responders and 6 non-responders) treated with LEN and determined 23 covariates related to functional T cell response measured prior to treatment and then correlated to treatment outcome. Of these 23 covariates, multiple T cell immune parameters were analyzed but were not associated with response including interferon-g (IFNg) production by CD4+ T cells (p=0.9) and CD8+ T cells (p=0.27), Tumor Necrosis Factor (TNF)-a production by CD4+ T cells (p=1.0) and CD8+ T cells (p=0.8), TCR-associated proliferation within the CD4+ (p=1.0) and CD8+ (p=0.4) compartment, CD4/CD8 ratio (p=0.3), percentage of CD4+ (p=0.5) and CD8+ (p=0.5) T lymphocytes, and the percentage of naïve and three different types of memory CD4+ T cells. Analysis was performed using two-group comparison statistical tests (two-sample t-test and Wilcoxon rank sum test) to compare responders (R) vs non-responders (NR). Only one factor was independently linked to LEN response. Results showed that a higher percentage of CD8 T cells (mean 56% in NR vs 32% in R) with a Terminal Effector Memory [TEM]) phenotype (CD45RA+/CD62L-) was associated with LEN failure (p=0.02). This population of T cells occurs at a low frequency in healthy individuals but can be induced to differentiate in vitro under constant exposure to long-term antigen and cytokine stimulation. We have shown previously that CD8+ TEM T cells are expanded in patients with impaired myelopoiesis due to immune dysregulation in Large Granular Lymphocyte (LGL) leukemia. In conclusion, these results suggest that CD8+ terminal effector memory expansion may be linked to immune deregulation in MDS and represents an important biomarker with negative predictive importance for LEN response in non-del(5q) low-risk MDS. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 61-61 ◽  
Author(s):  
Melissa D Docampo ◽  
Christoph K. Stein-Thoeringer ◽  
Amina Lazrak ◽  
Marina D Burgos da Silva ◽  
Justin Cross ◽  
...  

Abstract INTRODUCTION: The intestinal microbiota is essential for the fermentation of fibers into the short-chain fatty acids (SCFA) butyrate, acetate and propionate. SCFA can bind to G-protein-coupled receptors GPR41, GPR43 and GPR109a to activate downstream anti-inflammatory signaling pathways. In colitis or graft versus host disease (GVHD), GPR43 signaling has been reported as an important regulator of intestinal homeostasis by increasing the pool of regulatory T cells. In contrast to GPR43, which binds preferentially propionate and acetate, GPR109a is the major receptor for butyrate. We and others have demonstrated that butyrate can ameliorate gastrointestinal injury during GVHD through enterocyte protection. Therefore, we hypothesized that GPR109a plays an important role in the pathophysiology of intestinal GVHD, focusing specifically on alloreactive T cells. METHODS AND RESULTS: Using mouse models of GVHD, we examined the role of the butyrate/niacin receptor, GPR109a in allogeneic hematopoietic cell transplantation (allo-HCT). First, we studied whether a genetic knock-out (KO) of GPR109a in transplant recipient mice affected GVHD, but GPR109a-KO recipient mice did not exhibit increased mortality from GVHD compared to wild type (WT) mice. We next investigated the role of GPR109a in the donor compartment by transplanting either BM or T cells from WT or GPR109a-KO mice into major MHC mismatched BALB/c host mice. Mice transplanted with B6 BM, with T cells from a GPR109a-KO mouse into BALB/c hosts displayed a lower incidence of lethal GVHD (Fig. 1A). To determine whether the attenuation of GVHD is intrinsic to GPR109a-KO T cells, we established BM chimeras and performed a secondary transplant by transplanting B6 BM + (B6 à Ly5.1) or (GPR109a à Ly5.1) T cells into BALB/c hosts. We observed the same improvement in survival in mice that received GPR109a-KO T cells. This indicates an intrinsic role for GPR109a specifically in the donor hematopoietic compartment. Having identified a T-cell specific requirement for GPR109a we next examined expression of GPR109a on WT T cells in vitro at baseline and following stimulation with CD3/28 and found GPR109a significantly upregulated on both CD4+ and CD8+ T cells after 72 hours of stimulation (Fig 1B). At steady state in vivo, we observed the same numbers and percentages of splenic effector memory, central memory, and naïve CD4+ T cells as well as regulatory T cells in WT B6 mice and GPR109a-KO mice, suggesting normal T cell development in the knockout mice. In an in vitro mixed lymphocyte reaction (MLR), GPR109a-KO CD4+ T cells become activated, proliferate, polarize and secrete cytokine (specifically IFNg) to the same level as WT CD4+ T cells, suggesting normal functional capacity. However, after allo-HCT in mice we observed significantly fewer CD4+ and CD8+ T cells, and specifically fewer effector memory CD4+ T cells (Fig. C), in the small and large intestines of mice that received GPR109a-KO T cells at day 7 post transplant. In contrast, we found significantly more regulatory T cells in the intestines (Fig. 1D) and the spleen of GPR1091-KO T cell recipients, while numbers and percentages of polarized Th1 and Th17 T cells were similar between the two groups. We further 16S rRNA sequenced the gut microbiota of mice at day 7 after transplant and observed an increased relative abundance of bacteria from the genus Clostridium (Fig. 1D) along with an increased concentration of cecal butyrate as measured by GC-MS (Fig. 1E). In a preliminary graft versus tumor (GVT) experiment, we found that mice that received A20 tumor cells and GPR109a-KO T cells exhibited increased survival compared to mice that received A20 tumor cells and WT T cells. These preliminary findings suggest that GPR109a-KO T cells maintain their graft versus tumor response while causing less GVHD, and exclude a defective functional capacity. CONCLUSIONS: We report a novel role of the butyrate/niacin receptor GPR109a on donor T cells in allo-HCT as a genetic knock-out on T cells attenuates lethal GVHD. As these T cells are tested as functionally intact, we propose that the reduction in overall T cells of KO T cell recipients may underlie the attenuation in GVHD. Furthermore, such a reduction in allograft-induced gut injury is accompanied by maintenance of the gut commensal Clostridium and butyrate production, which is known to protect the intestinal epithelium and increases the regulatory T cell pool. Disclosures No relevant conflicts of interest to declare.


Author(s):  
Maud Wilhelm ◽  
Amandeep Kaur ◽  
Marion Wernli ◽  
Hans H Hirsch

Abstract Background BK polyomavirus (BKPyV) remains a significant cause of premature kidney transplant failure. In the absence of effective antivirals, current treatments rely on reducing immunosuppression to regain immune control over BKPyV replication. Increasing BKPyV-specific CD8 T cells correlate with clearance of BKPyV DNAemia in kidney transplant patients. We characterized a novel approach for expanding BKPyV-specific CD8 T cells in vitro using 27mer-long synthetic BKPyV peptides, different types of antigen-presenting cells, and CD4 T cells. Methods Langerhans cells and immature or mature monocyte-derived dendritic cells (Mo-DCs) were generated from peripheral blood mononuclear cells of healthy blood donors, pulsed with synthetic peptide pools consisting of 36 overlapping 27mers (27mP) or 180 15mers (15mP). BKPyV-specific CD8 T-cell responses were assessed by cytokine release assays using 15mP or immunodominant 9mers. Results BKPyV-specific CD8 T cells expanded using 27mP and required mature Mo-DCs (P = .0312) and CD4 T cells (P = .0156) for highest responses. The resulting BKPyV-specific CD8 T cells proliferated, secreted multiple cytokines including interferon γ and tumor necrosis factor α, and were functional (CD107a+/PD1–) and cytotoxic. Conclusions Synthetic 27mP permit expanding BKPyV-specific CD8 T-cell responses when pulsing mature Mo-DCs in presence of CD4 T cells, suggesting novel and safe approaches to vaccination and adoptive T-cell therapies for patients before and after kidney transplantation.


1990 ◽  
Vol 172 (4) ◽  
pp. 1065-1070 ◽  
Author(s):  
Y Kawabe ◽  
A Ochi

The cellular basis of the in vitro and in vivo T cell responses to Staphylococcus enterotoxin B (SEB) has been investigated. The proliferation and cytotoxicity of V beta 8.1,2+,CD4+ and CD8+ T cells were observed in in vitro response to SEB. In primary cytotoxicity assays, CD4+ T cells from control spleens were more active than their CD8+ counterparts, however, in cells derived from SEB-primed mice, CD8+ T cells were dominant in SEB-specific cytotoxicity. In vivo priming with SEB abrogated the response of V beta 8.1,2+,CD4+ T cells despite the fact that these cells exist in significant number. This SEB-specific anergy occurred only in V beta 8.1,2+,CD4+ T cells but not in CD8+ T cells. These findings indicate that the requirement for the induction of antigen-specific anergy is different between CD4+ and CD8+ T cells in post-thymic tolerance, and the existence of coanergic signals for the induction of T cell anergy is suggested.


2010 ◽  
Vol 207 (3) ◽  
pp. 505-520 ◽  
Author(s):  
Xiaoyuan Huang ◽  
Xiangyang Bai ◽  
Yang Cao ◽  
Jingyi Wu ◽  
Mei Huang ◽  
...  

Angiogenesis is increasingly recognized as an important prognosticator associated with the progression of lymphoma and as an attractive target for novel modalities. We report a previously unrecognized mechanism by which lymphoma endothelium facilitates the growth and dissemination of lymphoma by interacting with circulated T cells and suppresses the activation of CD4+ T cells. Global gene expression profiles of microdissected endothelium from lymphoma and reactive lymph nodes revealed that T cell immunoglobulin and mucin domain–containing molecule 3 (Tim-3) was preferentially expressed in lymphoma-derived endothelial cells (ECs). Clinically, the level of Tim-3 in B cell lymphoma endothelium was closely correlated to both dissemination and poor prognosis. In vitro, Tim-3+ ECs modulated T cell response to lymphoma surrogate antigens by suppressing activation of CD4+ T lymphocytes through the activation of the interleukin-6–STAT3 pathway, inhibiting Th1 polarization, and providing protective immunity. In a lymphoma mouse model, Tim-3–expressing ECs promoted the onset, growth, and dissemination of lymphoma by inhibiting activation of CD4+ T cells and Th1 polarization. Our findings strongly argue that the lymphoma endothelium is not only a vessel system but also a functional barrier facilitating the establishment of lymphoma immune tolerance. These findings highlight a novel molecular mechanism that is a potential target for enhancing the efficacy of tumor immunotherapy and controlling metastatic diseases.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1071-1071
Author(s):  
Melody M. Smith ◽  
Cynthia R. Giver ◽  
Edmund K. Waller ◽  
Christopher R. Flowers

Abstract Ex vivo modification of donor lymphocytes with purine analogs (mDL) may help to minimize graft versus host disease (GvHD) while providing beneficial graft versus leukemia (GvL) effects. In a murine model system, we have shown that allogeneic donor splenocytes, treated with fludarabine ex vivo have significantly reduced GvHD activity when transferred to irradiated recipient mice, and retain anti-viral and GvL activities (Giver, 2003). This effect appears to be mediated by relative depletion of donor CD4 CD44low, “naive” T-cells. As a first step toward developing mDL for use in patients, we sought to evaluate the effects of ex vivo fludarabine exposure on human T-cell subsets, and to determine the minimum dose of fludarabine required to achieve this effect. Methods: Peripheral blood mononuclear cell samples from 6 healthy volunteers were evaluated at 0, 24, 48, and 72 hour time points after ex vivo incubation in varying dosages of fludarabine: 2, 5, and 10(n=3) mcg/ml. Fludarabine incubated samples were compared to samples that received no fludarabine (untreated). The total viable cell number was determined and the fractions and absolute numbers of viable CD4 and CD8 naïve and memory T-cells were determined using flow cytometry after incubation with 7-AAD (dead cell stain), CD4, CD8, CD45RA, CD62L, and CCR7 antibodies, and measuring the total viable cells/ml. Results: The numbers of viable CD4 and CD8 T-cells remained relatively stable in control cultures. Without fludarabine, the average viability at 72 hr of naive and memory T-cells were 92% and 77% for CD4 and 86% and 63% for CD 8 (Fig. 1A). Naive CD4 T-cells were more sensitive to fludarabine-induced death than memory CD4 cells. At 72 hr, the average viability of fludarabine-treated naive CD4 T-cells was 33% at 2 mcg/ml (8.2X the reduction observed in untreated cells) and 30% at 5 mcg/ml, while memory CD4 T-cells averaged 47% viability at 2 mcg/ml (2.3X the reduction observed in untreated cells) (Fig. 1B) and 38% at 5 mcg/ml. The average viability of naive CD8 T-cells at 72 hr was 27% at 2 mcg/ml and 20% at 5 mcg/ml, while memory CD8 T-cell viability was 22% at 2 mcg/ml and 17% at 5 mcg/ml. Analyses on central memory, effector memory, and Temra T-cells, and B-cell and dendritic cell subsets are ongoing. The 5 and 10 mcg/ml doses also yielded similar results in 3 initial subjects, suggesting that 2 mcg/ml or a lower dose of fludarabine is sufficient to achieve relative depletion of the naive T-cell subset. Conclusions: Future work will determine the minimal dose of fludarabine to achieve this effect, test the feasibility of using ex vivo nucleoside analog incubation to reduce alloreactivity in samples from patient/donor pairs, and determine the maximum tolerated dose of mDL in a phase 1 clinical trial with patients at high risk for relapse and infectious complications following allogeneic transplantation. Figure Figure


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4962-4962
Author(s):  
JianXiang Zou ◽  
Jeffrey S. Painter ◽  
Fanqi Bai ◽  
Thomas P. Loughran ◽  
P.K. Epling-Burnette

Abstract Background: Clonal proliferation by mature Large Granular Lymphocytes is associated with LGL leukemia. This expansion of CD3− NK cells or CD3+ T cells may be the result of chronic antigen stimulation by autoantigens or viral antigens. In association with T cell lymphoproliferation, approximately 45% of patients with LGL leukemia have severe neutropenia (absolute neutrophil count <0.5×109/L) and 20% of patients have transfusion-dependent anemia. Homeostatic mechanisms normally modulate the generation of naïve and memory T cell pools and regulate the T cell repertoire; however, the pathways elicited during T memory differentiation, maintenance and expansion are not fully characterized. The goal of this work was to characterize the homeostatic mechanisms that regulate LGL leukemia. Methods: Peripheral blood mononuclear cells were isolated from patients with LGL leukemia and normal controls. We performed multiplex TCR-Vβ (CDR3) PCR on cells from 16 LGL patients to identify clonal T cell proliferation. The percentage of CD3+ T cells that expressed each of the TCR-Vβ families was determined in 20 healthy donors to establish the mean and standard deviation (S.D.) of the control population. Naïve and memory CD4 and CD8 T cell sub-populations were segregated by expression of CD45RA and CD62L expression by flow cytometry and T cell proliferation was assessed by Brdu incorporation in CD4+ and CD8+ T cells. Results: The absolute number of CD4+ T cells was reduced in LGL patients compared to normal donors and T cell clones were characterized by a CD8+ phenotype. By flow cytometry, expansion of a single Vβ clonal population occurred in 8 of 16 patients (50%), two clones were present in 4 of 16 patients (25%), and three clones in 4 of 16 patients (25%). The immunophenotype of TCR Vβ+ clonal T cells was CD8 positive, CD57 positive, CD28 negative, CD25 negative, and NKG2D (NKG2-family) positive and CD244 (2B4) positive. Three patients examined expressed Killer-Immunoglobulin-like (KIR) receptors. Further phenotype analysis showed that there were fewer than normal CD4+ naïve (CD4+/CD45RA+/CD62L+) T cells (23%±16 vs. 41%± 15, P=0.04 by a t test) in LGL patients. CD4+ T cells from patients had reduced proliferation in response to antigen stimulation. The reduction in CD4+ naïve T cells was associated with increased percentages of CD4+/CD45RA−/CD62L+ central memory T cells (P<0.05). Reduced percentage of naive CD8+ T cells in detected in LGL leukemia patients. In addition, CD4+ central memory cells were also significantly reduced in patients. CD8+ T cells were primarily characterized by a CD45RA+/CD62L− terminal effector memory phenotype that was significantly increased compared to normal donors (mean 75% ± 13 in patients vs 30% ± 13 in normal controls, P<0.0001). In the presence of a skewed repertoire and terminal effector memory cell accumulation, antigen-induced proliferation of CD8+ T cells in LGL did not differ from normal controls (13% ± 11 in patients vs. 9% ± 3 in normal controls, P=0.3). Conclusions: These results suggest that leukemic LGL represent the accumulation of CD8+ terminal effector memory cells with the capacity for increased proliferation. Our findings suggest that normal homeostatic signals are impaired in LGL leukemia that limits the terminal CD8 differentiation phase of an immune response.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3647-3647
Author(s):  
JianXiang Zou ◽  
Dana E Rollison ◽  
David Boulware ◽  
Elaine M. Sloand ◽  
Loretta Pfannes ◽  
...  

Abstract BACKGROUND: A subset of patients with Myelodysplastic Syndrome (MDS) responds well to immunosuppressive therapy (IST) and the only validated predictor of response is age, with younger patients faring much better than older patients. Hematologic improvement on immunosuppressive therapy is associated with a survival benefit with response rates ranging from 15% to 50%, clearly comparable or better than results with other existing therapies in MDS. Despite progress in the basic understanding of immune pathobiology of MDS and a clear therapeutic value, including improved long-term survival, IST including anti-thymocyte globulin (ATG) and/or cyclosporine A (CyA) is rarely offered to MDS patients in the U.S. due to uncertain criteria for selection of patients and potential toxicities. In addition, there is an underlying concern that inappropriate use of immunosuppressive therapy may negatively impact risk for leukemia progression, which occurs in 30–40% of MDS cases. The long-term goal of this study is to identify an immune signature that has postive predictive power for IST responsiveness. METHODS: To determine the effect of age on T-cell homeostasis and function and IST response, we performed a study of 54 MDS patients compared to 37 healthy controls. In a pilot study, T cell abnormalities associated with response to equine anti-lymphocyte globulin (eATG, lymphoglobulin, Pfizer, Inc) and/or CyA was studied in 12 younger MDS patients composed of 6 responders and 6 non-responders. RESULTS: CD4+ T-cells are normally present in the peripheral blood lymphocyte pool at 2 to 4 times greater than that of CD8+ T-cells, and diminished CD4:CD8 ratio has been previously shown to correlate with poor survival outcome in MDS. Similar to previous reports, we found that the age-adjusted CD4:CD8 ratio was reduced in MDS patients compared to healthy controls (p-value <0.0001) Interestingly, our analysis revealed that inadequate CD4+ rather than expansion of CD8+ T-cells was associated with a lower ratio in this group of MDS patients that included both lower and higher risk MDS patients defined by the International Prognostic Scoring System (IPSS). Analysis of the percentage of T-cells with naïve and memory phenoytpes using CD45RA and CD62L display, demonstrated positive correlations between age and both % CD62L positive naïve cells and central memory CD4+ T-cells (naïve: slope=0.39, p=0.12; central memory: slope=1.26, p=0.005). Furthermore, the proportions of CD62L- CD4+ T-cell populations, including effector memory and terminal effector memory T-cells, were greater in younger MDS patients (slope=−0.82, p=0.08 and slope=−0.83, p=0.015, respectively) suggesting a possible relationship to IST responsiveness. Specific characteristics associated with response to eATG in the pilot study of 12 younger patients included altered distribution of T cell populations (i.e., lower CD4/CD8 ratio, p<0.001) and higher constitutive proliferative index of the T cell populations (p=0.03 CD4+ and p=0.02 CD8+ T-cells, respectively). We also found that hematological response was associated with blockade of homeostatic proliferation of T cells associated with reconstitution of the naïve T cell pool. Reduction in CD4+ T-cells and expansion of autoreactive CD8+ T-cells suggests that apoptotic conditions may drive the expansion of cells through homeostatic cytokines such as IL-7, IL-15, and/or IL-21, which are all cytokines of the IL-2Rγc family that control homeostatic proliferation. Comparisons of the IL-7Ra, IL-15Ra, IL-2Ra, and IL-21Ra subunit demonstrated overexpression of IL-21Ra in patients 35.4% ± 3.4 in CD4+ T-cells and 31.8% ± 4.3 in CD8+ T-cells compared to healthy donors 0.9% ± 0.5 and 0.5% ± 0.5 (p<0.0001). CONCLUSIONS: Association between the T-cell abnormalities reported in this study and response to IST strongly suggests that aberrant T-cell homeostasis may represent a critical determinant of autoimmunity in MDS that may have positive predictive power for response to IST.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 206-206 ◽  
Author(s):  
Sonja Schmucker ◽  
Mario Assenmacher ◽  
Jurgen Schmitz ◽  
Anne Richter

Abstract Adoptive transfer of virus-specific T cells is a promising therapy for the treatment of infections in immunocompromised patients. Virus-specific T cells can readily be obtained from antigen-experienced, but not naïve donors. In this study we describe a cell culture system for the in vitro generation of CMV-specific T cells from naive T cells derived from CMV-seronegative donors. We isolated naïve T cells by magnetic depletion of non-T cells, CD25+ regulatory T cells, and CD45RO+ effector and memory T cells from peripheral blood mononuclear cells (PBMC) of CMV-seronegative donors. These naïve T cells were co-cultured with autologous mature monocyte-derived DC (MoDC) loaded with a pool of overlapping peptides from the CMV protein pp65. CD3-depleted autologous PBMC were used as feeder cells and CD28 antibody, IL-2, IL-7, and IL-15 were added to the culture. Already only 9–13 days after starting the priming culture, frequencies of 0.0024% and 0.009% pp65495–503/A2-tetramer+ cells among CD8+ T cells were found for 2 HLA-A2+ blood donors. In contrast pp65495–503/A2-tetramer+ T cells were not detectable when naive T cells were cultured with unpulsed MoDC. Tetramers are suitable tools for the identification of antigen-specific T cells but are restricted to single epitopes of mainly CD8+ T cells. To analyze primed CD4+ T cells as well as CD8+ T cells having specificities other than for the peptide pp65495–503, we looked for upregulation of the activation marker CD137 after a second stimulation and found increased frequencies of CD137+ CD4+ T cells as well as CD137+ CD8+ T cells in the pp65-primed cell cultures only when restimulated with the peptide pool of pp65. Because IFN-γ is important for the control of CMV infection, we studied the capability of the in vitro primed pp65-specific CD4+ and CD8+ T cells to produce this cytokine. Restimulation of the T cells with pp65 peptide pool induced IFN-γ secretion in up to 3.9% of the CD8+ T cells and up to 3.8% of the CD4+ T cells in each of six donors tested. No specific IFN-γ production was detected after restimulation with an irrelevant IE-1 peptide pool. As expected the frequency of pp65-specific T cells in the priming cultures is low. For generation of T cell lines, we magnetically enrich pp65- specific T cells according to their IFN-γ secretion using the cytokine secretion assay technology. After further cultivation for 2 weeks the antigen-specificity of the expanded T cells was again evaluated. Only if restimulated with the pp65 peptide pool 56.6% of the CD4+ T cells showed upregulated expression of the activation marker CD154 (CD40L). Cytokine analysis of the cells revealed IFN-γ production in 40.2% of the CD4+ T cells, of which 36% co-expressed IL-2, indicating the functionality of the in vitro primed and expanded T cells. In conclusion, we established a cell culture system for in vitro priming of CMV-specific CD4+ and CD8+ T cells derived from peripheral blood of donors not infected by CMV. This should extend the application of adoptive T cell therapy to patients for whom immune donors are not available.


Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 1373-1373
Author(s):  
JianXiang Zou ◽  
Jeffrey S Painter ◽  
Fanqi Bai ◽  
Lubomir Sokol ◽  
Thomas P. Loughran ◽  
...  

Abstract Abstract 1373 Introduction: LGL leukemia is associated with cytopenias and expansion of clonally-derived mature cytotoxic CD8+ lymphocytes. The etiology of LGL leukemia is currently unknown, however, T cell activation, loss of lymph node homing receptor L-selectin (CD62L), and increased accumulation of T cells in the bone marrow may lead to suppressed blood cell production. The broad resistance to Fas (CD95) apoptotic signals has lead to the hypothesis that amplification of clonal cells occurs through apoptosis resistance. However, the proliferative history has not been carefully studied. To define possible mechanism of LGL leukemia expansion, T cell phenotype, proliferative history, and functional-related surface marker expression were analyzed. Methods: Peripheral blood mononuclear cells (PBMCs) were obtained from 16 LGL leukemia patients that met diagnostic criteria based on the presence of clonal aβ T cells and >300 cells/ml CD3+/CD57+ T cells in the peripheral blood. Samples were obtained from 10 age-matched healthy individuals from the Southwest Florida Blood Services for comparisons. Multi-analyte flow cytometry was conducted for expression of CD3, CD4/8, CD45RA, CD62L, CD27, CD28, CD25, CD127, IL15Ra, IL21a, CCR7 (all antibodies from BD Biosciences). The proliferative index was determined by Ki67 expression in fixed and permeabilized cells (BD Biosciences) and the proliferative history in vivo was assessed by T-cell-receptor excision circle (TREC) measurement using real-time quantitative PCR (qRT-PCR) in sorted CD4+ and CD8+ T cells. TRECs are episomal fragments generated during TCR gene rearrangements that fail to transfer to daughter cells and thus diminish with each population doubling that reflects the in vivo proliferative history. Results: Compared to healthy controls, significantly fewer CD8+ naïve cells (CD45RA+/CD62L+, 8.4 ± 10.8 vs 24.48 ± 11.99, p=0.003) and higher CD8+ terminal effector memory (TEM) T cells (CD45RA+/CD62L-, 67.74 ± 28.75 vs 39.33 ± 11.32, p=0.007) were observed in the peripheral blood. In contrast, the percentage of CD4+ naïve and memory cells (naïve, central memory, effector memory, and terminal effector memory based on CD45RA and CD62L expression) was similar in patients as compared to controls. The expression of CD27 (31.32 ± 34.64 vs 71.73 ± 20.63, p=0.003) and CD28 (31.38 ± 31.91 vs 70.02 ± 22.93, p=0.002) were lower in CD8+ T cell from patients with LGL leukemia and this reduction predominated within the TEM population (17.63±24.5 vs 70.98±22.5 for CD27, p<0.0001 and 13±20.5 vs 69.43± 21.59 for CD28, p<0.0001). Loss of these markers is consistent with prior antigen activation. There was no difference in CD25 (IL2Ra, p=0.2) expression on CD4+ or CD8+ T cells, but CD127 (IL7Ra, p=0.001), IL15Ra, and IL21Ra (p=0.15) were overexpressed in TEM CD8+ T cell in patients vs controls. All of these cytokine receptors belong to the IL2Rβg-common cytokine receptor superfamily that mediates homeostatic proliferation. In CD8+ T cells in patients, the IL-21Ra was also overexpressed in naïve, central and effector memory T cells. The topography of the expanded CD8+ T cell population was therefore consistent with overexpression of activation markers and proliferation-associated cytokine receptors. Therefore, we next analyzed Ki67 expression and TREC DNA copy number to quantify actively dividing cells and determine the proliferative history, respectively. We found that LGL leukemia patients have more actively dividing CD8+ TEM T cells compared to controls (3.2 ± 3.12 in patients vs 0.44 ± 0.44 in controls, p=0.001). Moreover, the TREC copy number in CD8+ T cells was statistically higher in healthy individuals after adjusting for age (177.54 ± 232 in patients vs 1015 ± 951 in controls, p=0.019). These results show that CD8+ cells in the peripheral compartment have undergone more population doublings in vivo compared to healthy donors. In contrast, the TREC copies in CD4+ T-cells were similar between LGL patients and controls (534.4 ± 644 in patients vs 348.78 ± 248.16 in controls, p>0.05) demonstrating selective cellular proliferation within the CD8 compartment. Conclusions: CD8+ T- cells are undergoing robust cellular activation, contraction in repertoire diversity, and enhanced endogenous proliferation in patients with LGL leukemia. Collectively, these results suggest that clonal expansion is at least partially mediated through autoproliferation in T-LGL leukemia. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 782-782 ◽  
Author(s):  
Marcus Butler ◽  
Philip Friedlander ◽  
Mary Mooney ◽  
Linda Drury ◽  
Martha Metzler ◽  
...  

Abstract Abstract 782 The goal of cellular immunotherapy is to build long-lasting anti-tumor immunologic “memory” in patients and reject tumors for a lifetime. Previously, we and others demonstrated that IL-15 promotes the generation of T cells with a central memory (CM) phenotype which have the capacity to persist and establish effective anti-tumor memory in vivo. Furthermore, it has been shown that CD83 delivers a CD80-dependent T cell stimulatory signal that allows T cells to be long-lived. Based on these findings, we developed a system to generate large numbers of long-lived antigen-specific CD8+ T cells with a memory phenotype. This in vitro culture system utilizes IL-15 and a standardized, renewable artificial antigen presenting cell (aAPC) which was produced by transducing CD80, CD83, and HLA-A*0201 to the human cell line, K562. This aAPC can uniquely support the priming and prolonged expansion of large numbers of antigen-specific CD8+ CTL which display a central/effector memory (CM/EM) phenotype, possess potent effector function, and can be maintained in vitro for >1 year without any feeder cells or cloning. We hypothesized that adoptive transfer of these CTL with a CM/EM phenotype should result in anti-tumor memory in humans even without lymphodepletion or high dose IL-2. For our “first-in-human” clinical study, we chose the melanoma antigen MART1 as a target antigen, since MART1-specific HLA-A*0201+-restricted precursor CTL are detectable in some melanoma patients and can be immunophenotyped pre-infusion. Autologous CD8+ T cells were stimulated weekly with peptide-pulsed human cell-based aAPC and expanded with low dose IL-2 and IL-15. After three weeks, polyclonal MART1 CTL were reinfused without additional lymphodepletion, chemotherapy, IL-2, or vaccination. Eight study participants have enrolled and received a total of 15 MART1 CTL infusions (31% MART1 multimer positivity, median). All but one subject received two reinfusions where the 2nd graft was produced from CD8+ T cells harvested two weeks after the 1st reinfusion. To date, ≥2×109 CTL with potent effector function and a CM/EM phenotype were successfully generated for all subjects. No dose limiting toxicities were observed at either Dose Level 1 (2×108/m2) or Dose Level 2 (2×109/m2). Clinical activity was observed with a response by RECIST criteria in 1 subject, which was confirmed by a negative PET/CT 100 days following the last CTL infusion. In addition, 1 patient experienced a mixed response, 1 had stable disease, 3 had progression, and 2 are currently on active therapy. Multimer staining showed that, immediately post infusion, the percentage of CD8+ T cells specific for MART1 temporarily increased in all subjects, with the highest (6.5%) observed in subject #7. In 4 subjects, sustained increases in the frequency of MART1 specific T cells by more than two-fold (range 2.0-10x) for ≥21 days were observed despite the fact that no exogenous cytokines or vaccination was administered. Moreover, an increase of detectable MART1 specific T cells which display a CM phenotype was observed in all evaluable subjects and was observed for ≥35 days in 6 of 8 subjects. In subject #2, the conversion of MART1 CTL immunophenotype from a naïve to a mixture of naïve/memory phenotypes was observed for more than 6 months. We identified 10 individual MART1 T cell clonotypes from peripheral CD45RA- memory T cells on day 21. Clonotypic TCR Vbeta CDR3 analysis revealed that CTL grafts contained 7 out of 10 of these clonotypes. Furthermore, 6 clonotypes persisted in the peripheral CD45RA- memory fraction on days 39, 67 and/or 132. In Subject #3, who showed a mixed clinical response, 5 individual MART1 T cell clonotypes were isolated from lung metastases. 4 out of 5 clones were included in the CTL grafts. This finding supports the possibility that infused CTL can traffic and localize to sites of disease. Intriguingly, in both subjects, we were able to identify MART1 CTL clonotypes that were not detectable in the CTL grafts but possibly emerged after CTL infusion, indicating that adoptive transfer of MART1-specific CTL may provoke a de novo antitumor response. Taken together, these results suggest that CM/EM MART1 CTL generated ex vivo using our cell-based artificial APC in the presence of IL-15 may persist in vivo and induce de novo anti-tumor responses. Further enhancement of anti-tumor activity may be achieved through vaccination, cytokine administration, and/or removal of cytokine sinks and inhibitory factors following appropriate lymphodepletion. Disclosures: No relevant conflicts of interest to declare.


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