scholarly journals Conditional deletion of cytokine receptor chains reveals that IL-7 and IL-15 specify CD8 cytotoxic lineage fate in the thymus

2012 ◽  
Vol 209 (12) ◽  
pp. 2263-2276 ◽  
Author(s):  
Tom M. McCaughtry ◽  
Ruth Etzensperger ◽  
Amala Alag ◽  
Xuguang Tai ◽  
Sema Kurtulus ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Conditional Knockout ◽  
Cytokine Receptor ◽  
T Cell Subsets ◽  
Cytotoxic T Cell ◽  
Lineage Specification ◽  
Class I Mhc ◽  
Mhc I

The thymus generates T cells with diverse specificities and functions. To assess the contribution of cytokine receptors to the differentiation of T cell subsets in the thymus, we constructed conditional knockout mice in which IL-7Rα or common cytokine receptor γ chain (γc) genes were deleted in thymocytes just before positive selection. We found that γc expression was required to signal the differentiation of MHC class I (MHC-I)–specific thymocytes into CD8+ cytotoxic lineage T cells and into invariant natural killer T cells but did not signal the differentiation of MHC class II (MHC-II)–specific thymocytes into CD4+ T cells, even into regulatory Foxp3+CD4+ T cells which require γc signals for survival. Importantly, IL-7 and IL-15 were identified as the cytokines responsible for CD8+ cytotoxic T cell lineage specification in vivo. Additionally, we found that small numbers of aberrant CD8+ T cells expressing Runx3d could arise without γc signaling, but these cells were developmentally arrested before expressing cytotoxic lineage genes. Thus, γc-transduced cytokine signals are required for cytotoxic lineage specification in the thymus and for inducing the differentiation of MHC-I–selected thymocytes into functionally mature T cells.

scholarly journals CRTAM determines the CD4+ cytotoxic T lymphocyte lineage

2015 ◽  
Vol 213 (1) ◽  
pp. 123-138 ◽  
Author(s):  
Arata Takeuchi ◽  
Mohamed El Sherif Gadelhaq Badr ◽  
Kosuke Miyauchi ◽  
Chitose Ishihara ◽  
Reiko Onishi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cytotoxic Activity ◽  
Cd4 T Cells ◽  
Intracellular Signaling ◽  
Ectopic Expression ◽  
T Cell Subsets ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Ifn Γ

Naive T cells differentiate into various effector T cells, including CD4+ helper T cell subsets and CD8+ cytotoxic T cells (CTL). Although cytotoxic CD4+ T cells (CD4+CTL) also develop from naive T cells, the mechanism of development is elusive. We found that a small fraction of CD4+ T cells that express class I–restricted T cell–associated molecule (CRTAM) upon activation possesses the characteristics of both CD4+ and CD8+ T cells. CRTAM+ CD4+ T cells secrete IFN-γ, express CTL-related genes, such as eomesodermin (Eomes), Granzyme B, and perforin, after cultivation, and exhibit cytotoxic function, suggesting that CRTAM+ T cells are the precursor of CD4+CTL. Indeed, ectopic expression of CRTAM in T cells induced the production of IFN-γ, expression of CTL-related genes, and cytotoxic activity. The induction of CD4+CTL and IFN-γ production requires CRTAM-mediated intracellular signaling. CRTAM+ T cells traffic to mucosal tissues and inflammatory sites and developed into CD4+CTL, which are involved in mediating protection against infection as well as inducing inflammatory response, depending on the circumstances, through IFN-γ secretion and cytotoxic activity. These results reveal that CRTAM is critical to instruct the differentiation of CD4+CTL through the induction of Eomes and CTL-related gene.

scholarly journals Relationship between Multiple Sclerosis-Associated IL2RA Risk Allele Variants and Circulating T Cell Phenotypes in Healthy Genotype-Selected Controls

Cells ◽  
2019 ◽  
Vol 8 (6) ◽  
pp. 634 ◽  
Author(s):  
Sophie Buhelt ◽  
Helle Bach Søndergaard ◽  
Annette Oturai ◽  
Henrik Ullum ◽  
Marina Rode von Essen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Interleukin 2 ◽  
T Cell Subsets ◽  
Multiparameter Flow Cytometry ◽  
Risk Genotype ◽  
Increased Risk ◽  
New Findings

Single nucleotide polymorphisms (SNPs) in or near the IL2RA gene, that encodes the interleukin-2 (IL-2) receptor α (CD25), are associated with increased risk of immune-mediated diseases including multiple sclerosis (MS). We investigated how the MS-associated IL2RA SNPs rs2104286 and rs11256593 are associated with CD25 expression on T cells ex vivo by multiparameter flow cytometry in paired genotype-selected healthy controls. We observed that MS-associated IL2RA SNPs rs2104286 and rs11256593 are associated with expression of CD25 in CD4+ but not CD8+ T cells. In CD4+ T cells, carriers of the risk genotype had a reduced frequency of CD25+ TFH1 cells (p = 0.001) and an increased frequency of CD25+ recent thymic emigrant cells (p = 0.006). Furthermore, carriers of the risk genotype had a reduced surface expression of CD25 in post-thymic expanded CD4+ T cells (CD31−CD45RA+), CD39+ TReg cells and in several non-follicular memory subsets. Our study found novel associations of MS-associated IL2RA SNPs on expression of CD25 in CD4+ T cell subsets. Insight into the associations of MS-associated IL2RA SNPs, as these new findings provide, offers a better understanding of CD25 variation in the immune system and can lead to new insights into how MS-associated SNPs contribute to development of MS.

scholarly journals The critical role of CD4+ T cells in PD-1 blockade against MHC-II–expressing tumors such as classic Hodgkin lymphoma

2020 ◽  
Vol 4 (17) ◽  
pp. 4069-4082
Author(s):  
Joji Nagasaki ◽  
Yosuke Togashi ◽  
Takeaki Sugawara ◽  
Makiko Itami ◽  
Nobuhiko Yamauchi ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Critical Role ◽  
Cd4 T Cell ◽  
Antitumor Effects ◽  
Cell Axis ◽  
Mhc I ◽  
Mhc Ii

Abstract Classic Hodgkin lymphoma (cHL) responds markedly to PD-1 blockade therapy, and the clinical responses are reportedly dependent on expression of major histocompatibility complex class II (MHC-II). This dependence is different from other solid tumors, in which the MHC class I (MHC-I)/CD8+ T-cell axis plays a critical role. In this study, we investigated the role of the MHC-II/CD4+ T-cell axis in the antitumor effect of PD-1 blockade on cHL. In cHL, MHC-I expression was frequently lost, but MHC-II expression was maintained. CD4+ T cells highly infiltrated the tumor microenvironment of MHC-II–expressing cHL, regardless of MHC-I expression status. Consequently, CD4+ T-cell, but not CD8+ T-cell, infiltration was a good prognostic factor in cHL, and PD-1 blockade showed antitumor efficacy against MHC-II–expressing cHL associated with CD4+ T-cell infiltration. Murine lymphoma and solid tumor models revealed the critical role of antitumor effects mediated by CD4+ T cells: an anti-PD-1 monoclonal antibody exerted antitumor effects on MHC-I−MHC-II+ tumors but not on MHC-I−MHC-II− tumors, in a cytotoxic CD4+ T-cell–dependent manner. Furthermore, LAG-3, which reportedly binds to MHC-II, was highly expressed by tumor-infiltrating CD4+ T cells in MHC-II–expressing tumors. Therefore, the combination of LAG-3 blockade with PD-1 blockade showed a far stronger antitumor immunity compared with either treatment alone. We propose that PD-1 blockade therapies have antitumor effects on MHC-II–expressing tumors such as cHL that are mediated by cytotoxic CD4+ T cells and that LAG-3 could be a candidate for combination therapy with PD-1 blockade.

Ex Vivo Fludarabine Selectively Depletes Human Naive T-Cell Subsets: A Step Toward Modifying Donor Lymphocyte Infusion.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1071-1071
Author(s):  
Melody M. Smith ◽  
Cynthia R. Giver ◽  
Edmund K. Waller ◽  
Christopher R. Flowers
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
Memory T Cells ◽  
Ex Vivo ◽  
T Cell Subsets ◽  
Effector Memory ◽  
Naïve T Cell ◽  
Naive T Cell

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

Development of a Cell Based Vaccine for the Immunotherapy of Acute and Chronic Leukemia by the Use of Autologous Dendritic Cells Loaded with Monoclonal Antibody Treated or Irradiated Leukemia Cells.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 4889-4889
Author(s):  
Caroline J. Duncan ◽  
Peter R.E. Johnson ◽  
Patrick H. Roddie
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Monoclonal Antibodies ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Subsets ◽  
Leukemia Cells ◽  
Cytotoxic T Cell ◽  
Dc Vaccine ◽  
Ctl Responses

Abstract Dendritic cell (DC) vaccines in leukemia show promise as a novel treatment modality however to date clinical evidence of efficacy has been limited. This is likely to be as a consequence of a combination of factors, which include insufficient immunogenicity of the DC vaccine and vaccination taking place in an environment adverse for generation of effective immune responses i.e. in patients with active disease. Our study aims to generate more efficient cytotoxic T cell (CTL) responses by improving DC uptake and presentation of leukemia cells in the remission state and will be applicable to both acute and chronic leukemias. Monoclonal antibodies (MoAbs) have been used to treat malignant cells prior to co-culture with DCs to enhance cross-presentation and generation of specific CTLs. We investigated whether this approach could improve DC induction of CTL responses in comparison to DCs loaded with UVB irradiated apoptotic leukemia cells. In this in vitro study we generated dendritic cells from adherent mononuclear cells (differentiation with GM-CSF and IL-4) of patients in remission following chemotherapy for acute myeloid leukemia (AML), chronic myeloid leukemia (CML) and chronic lymphocytic leukemia (CLL). The immature DCs were loaded with autologous leukemia cells from the patients’ presentation samples. The presentation leukemia cells were treated with either UVB irradiation or appropriate monoclonal antibodies (the anti-CD33 MoAb Mylotarg in AML and CML; the anti CD20 MoAb Rituximab or the anti-CD 52 MoAb Alemtuzumab in CLL). Apoptosis was assessed by Annexin/Propidium iodide labelling. Treatment of the leukemia cells by different MoAbs induced varying degrees of apoptosis. DC uptake of antibody treated or apoptotic leukemia cells was assessed by dual colour staining. Leukemia cells were stained with PKH and DCs labelled with FITC-CD80 or CD86. DC uptake was more efficient with MoAb treated cells irrespective of the degree of apoptosis induced by the MoAb. DCs were matured with TNFa for two days then co-cultured with autologous T cells for one week. T cell subsets and Regulatory T cells were assessed on the presentation and remission samples.The T cells were harvested and their cytoxicity assessed in an Interferon Gamma (IFNg) ELISPOT assay where the unmodified blasts were used as stimulators. Initial results show enhanced anti-leukemia activity in the MoAb treated group as compared to the irradiated group. A similar set up using allogeneic DCs and T cells confirmed the augmentation of CTL responses with MoAb treatment of leukemia cells.The use of MoAb in this setting shows promise for improvement in the success and applicability of DC vaccine strategies in leukemia.

PD-1+ T Cell Subsets in Follicular Lymphoma Tumor Microenvironment and Their Implications for Prognosis and Therapy

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 2648-2648
Author(s):  
Fuliang Chu ◽  
Wencai Ma ◽  
Tomohide Yamazaki ◽  
Myriam Foglietta ◽  
Durga Nattama ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Follicular Lymphoma ◽  
Cd8 T Cells ◽  
Cd4 T Cells ◽  
T Cell Subsets ◽  
Prognostic Impact ◽  
T Cell Exhaustion ◽  
Cell Exhaustion

Abstract Abstract 2648 Background: Programmed death (PD)-1, a coinhibitory receptor expressed by effector T cells (Teffs) is highly expressed on intratumoral T cells (mean 61%, range 34–86% for CD4+ T cells and mean 44%, range 31–69% for CD8+ T cells) in follicular lymphoma (FL), a finding associated with impaired ability to recognize autologous tumor (Nattamai et al, ASH 2007). Hence, PD-1 expression would be expected to confer an unfavorable prognosis in FL. However, correlation of PD-1 with clinical outcome in FL has been inconsistent with two studies showing favorable (Carreras et al, J Clin Oncol 2009; Wahlin et al, Clin Cancer Res 2010) and one study showing unfavorable (Richendollar et al, Hum Pathol 2011) outcome. While differences in method of analysis and type of treatment may explain the disparate results, a more complex model may be necessary to understand the prognostic impact of PD-1 in FL as PD-1 is expressed not only on antitumor Teffs but also on protumor follicular helper T cells (Tfh) and regulatory T cells (Tregs). Methods: To determine the nature of PD-1+ T cells in FL we performed comprehensive genomic and immunologic studies. By flow cytometry, we observed that the intratumoral CD4+ T cells in FL may be categorized into 3 subsets based on PD-1 expression - PD-1 high (PD-1hi), intermediate (PD-1int), and low (PD-1lo). The intratumoral CD8+ T cells consisted of PD-1int and PD-1lo subsets. The 3 CD4+ T cell subsets were FACSorted from FL tumors (n=3) and whole genome gene expression profiling (GEP) was performed. T cell subsets sorted similarly from tonsils served as controls for reactive follicular hyperplasia (FH) (n=3). Differentially expressed genes in GEP studies were confirmed at the mRNA level by real-time PCR (n=5) and at the protein level by flow cytometry when antibodies were available (n=5–10). Results: Our results suggested that CD4+PD-1hi T cells are Tfh cells (CXCR5hiBcl6hi ICOShiCD40LhiSAPhiPRDM1loIL-4hiIL-21hi); the CD4+PD-1int T cells consisted of a mixture of activated Teffs (CD45RO+CD45RA−) including Th1 (Tbet+IFNg+), Th2 (IL-10+), and Th17 cells (RORc+IL-17+), and Tregs (Foxp3+CD25hiCD127lo); and the CD4+PD-1lo T cells consisted of a mixture of activated Teffs (CD45RO+CD45RA− but IFNg−IL-4−IL-10−IL-17−), Tregs, and naïve T cells (CD45RO−CD45RA+CCR7+). Although these subsets were present in both FL and FH, there were important differences. IL-4 expression was significantly higher in Tfh in FL vs. FH and may play a role in the pathogenesis of FL. IL-17 expression was low and expression of coinhibitory molecules BTLA and CD200 was high in CD4+PD-1int T cells in FL vs. FH. BTLA and CD200 were also increased in CD8+PD-1int T cells in FL vs. FH. However, other coinhibitory molecules (LAG-3, Tim-3, CD160, CTLA-4, CD244, KLRG1) were not significantly different between FL and FH. CD4+PD-1int T cells also had higher expression of BATF, a transcription factor associated with T cell exhaustion in FL vs. FH. Together, these results suggest that the CD4+PD-1int T cells in FL may be in a state of T cell exhaustion whereas the CD4+PD-1int T cells in FH may represent recently activated Teffs. Consistent with this, blocking PD-1 with anti-PD-1 blocking antibody significantly enhanced proliferation and the production of Th1 (IFNg, TNFa) but not Th2 (IL-4, IL-5, IL-10, IL-13) cytokines by intratumoral CD4+ and CD8+ T cells in response to stimulation with autologous FL tumor cells (n=3). As expected, Tregs were increased in number in FL vs. FH and were present in the PD-1int and PD-1lo T cell subsets. We found 74% (range 40–97%) of FL Tregs expressed PD-1. Among the CD4+PD-1lo and CD8+PD-1lo T cells, there were more activated Teffs and fewer naïve T cells in FL vs. FH. Conclusions: Our results suggest that the PD-1+ T cells in FL are comprised of a mixture of antitumor Teffs and protumor Tfh and Tregs. The prognostic impact of PD-1+ T cells in FL may dependent on the relative frequency of these subsets as ligation of PD-1 may produce favorable (inhibition of protumor Tfh and Tregs) or unfavorable (inhibition of antitumor Teffs) outcomes by inhibiting or promoting tumor growth, respectively. Conversely, our results imply that agents that block PD-1/PD-ligand pathway may have the opposite effect on these T cell subsets and enumeration of the intratumoral PD-1+ T cell subsets may serve as biomarker to predict response to these agents in FL and possibly other B-cell malignancies. Disclosures: Dong: GSK: Consultancy; Genentech: Honoraria; Tempero: Consultancy; Ono: Consultancy; AnaptysBio: Consultancy. Neelapu:Cure Tech Ltd: Research Funding.

A Variety of T-Cell Subsets Contribute to CD4+ T-Cell Infiltration in Diffuse Large B-Cell Lymphoma and Both Total CD4+ and CD4+FoxP3+ T-Cell Numbers Predict Clinical Outcome,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3684-3684
Author(s):  
Matthew J Ahearne ◽  
Kaljit S Bhuller ◽  
Roger Hew ◽  
Giovanna Roncador ◽  
Martin J.S. Dyer ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Clinical Outcome ◽  
Cd4 T Cells ◽  
T Cell Subsets ◽  
Cd4 T Cell ◽  
Cell Infiltration ◽  
Good Clinical Outcome ◽  
Logrank Test ◽  
Tfh Cells

Abstract Abstract 3684 CD4+ T-cells can be distinguished into subsets on the basis of surface marker expression and growth factor production. Follicular helper T-cells (Tfh cells) are characterized by the co-expression of surface markers (CD4, ICOS, PD1 and CXCR5) and nuclear BCL6. Normal germinal centre formation requires Tfh cells but is repressed by another CD4+ T-cell subset, Tregs, (demonstrating CD4 and CD25 expression with nuclear FoxP3). The numbers and architecture of infiltrating T-cells predict clinical outcome in follicular lymphoma but although T-cells are a component of diffuse large B cell lymphoma (DLBCL), the relative numbers of CD4+ T-cells and their Tfh and Treg subsets or their association with clinical outcome is not known. We used immunohistochemistry to investigate infiltration by total CD4+, Treg and Tfh cells in cases (n=23) from one centre. The male:female was 1.3:1.0, the age range was 30 to 78 years (median 65 years) and the anticipated association between overall survival and LDH (logrank test, P=0.02) was observed. Patients were treated with R-CHOP with a 21-day cycle. Histological sections were stained with anti-CD4, anti-PD1 and anti-FoxP3 antibodies. For each antibody the area of staining was measured using ImageJ software from 10 high power fields from the same area of each histological section. Tfh cells were identified by strong surface expression of PD1 and Tregs by nuclear expression of FoxP3. CD4+ T-cell infiltration varied by ∼50-fold, and could be diffuse or focal. In 13 cases (57%) the majority of CD4+ T-cells were neither FoxP3+ nor PD1+. Total CD4+ T-cell numbers were positively correlated with FoxP3 (P=0.04) (Figure 1) and with PD1 (P=0.009) (Figure 2) expressing cells suggesting that these subsets were expanded as part of a reaction to the lymphoma capable of stimulating several CD4+ T-cell subsets. High CD4+ (Figure 3) and PD1+ staining predicted good clinical outcome (logrank test, P=0.08) with median survival not being reached at 5 years, but the amount of FoxP3+ staining appeared to be a superior prognostic marker (logrank test, P=0.0069) (Figure 4). There was no association between the cell of origin classification of DLBCL (GCB or ABC) as defined immunohistochemically, and CD4, FoxP3 or PD1 expression. In summary, we have shown that numbers of infiltrating CD4+ T-cells vary between cases of DLBCL and comprises several T-cell subsets including Treg and Tfh cells. No consensus has been reached on the clinical significance of FoxP3+ cell infiltration in DLBCL. Whilst some workers have shown FoxP3 to be associated with a good clinical outcome (Tzankov A., et al. 2008; Lee N., et al. 2008), others have not found a relationship to prognosis (Hasselblom S. et al., 2007). Our data shows that the FoxP3+ Treg cell subset is associated with good clinical outcome but surprisingly we found that both increased total CD4+ T-cells and PD1+ Tfh cells also carry a good prognosis. Disclosures: Wagner: Roche: Honoraria.

Therapy of B Cell Malignancies with CD19-Specific Chimeric Antigen Receptor-Modified T Cells of Defined Subset Composition

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 384-384 ◽  
Author(s):  
Cameron J Turtle ◽  
Daniel Sommermeyer ◽  
Carolina Berger ◽  
Michael Hudecek ◽  
David M Shank ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
B Cell ◽  
Cd4 T Cells ◽  
Research Funding ◽  
T Cell Subsets ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Car T Cells ◽  
Car T

Abstract BACKGROUND: The adoptive transfer of CD19-specific chimeric antigen receptor-modified (CD19 CAR) T cells is a promising strategy for treating patients with CD19+ B cell acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), and non-Hodgkin lymphoma (NHL). Dramatic responses have been observed in a subset of patients receiving CD19 CAR T cell therapy, and prior studies suggest that persistence of transferred T cells may correlate with the extent of tumor regression. The use of unselected T cells to prepare CAR T cells results in variation in the phenotypic composition of the infused product in individual patients, making it difficult to determine whether particular T cell subsets contribute to efficacy and/or toxicity. Studies in our lab demonstrated that genetically modified effector T cells derived from purified T cell subsets differ in the capacity to persist in vivo after adoptive transfer, and that a combination of CAR-modified CD8+ central memory (TCM) and CD4+ T cells provides optimal antitumor activity in tumor xenograft models. Based on these data, we designed the first clinical trial in which patients with CD19+ B cell malignancies receive CD19 CAR T cells comprised of a defined composition of CD8+ TCM and CD4+T cells engineered to express a CD19 CAR. METHODS: Patients with relapsed or refractory CD19+ ALL, CLL or NHL are eligible for this phase I/II study. CD8+ TCM and CD4+ T cells were separately enriched by immunomagnetic selection from a leukapheresis product from each patient, and cryopreserved. The CD8+ TCM and CD4+ T cells were stimulated in independent cultures with anti-CD3/anti-CD28 paramagnetic beads, and transduced with a lentivirus encoding the murine FMC63 anti-CD19 scFv, 4-1BB and CD3 zeta signaling domains. After in vitro expansion, the cell product for infusion was formulated in a 1:1 ratio of CD4+:CD8+ CAR+ T cells. A truncated non-functional human epidermal growth factor receptor (EGFRt) encoded in the transgene cassette allowed identification of transgene-expressing T cells by flow cytometry. Lymphodepleting chemotherapy was administered followed by infusion of EGFRt+ CAR T cells at one of three dose levels (2 x 105 EGFRt+ cells/kg, 2 x 106 EGFRt+ cells/kg, 2 x 107 EGFRt+cells/kg). RESULTS: Twenty patients with relapsed or refractory ALL (n = 9), NHL (n = 10) or CLL (n = 1), including those who failed prior autologous (n = 4) or allogeneic (n = 4) stem cell transplant have been treated on the trial. Fifteen of 20 treated patients received a product that conformed to the prescribed CD8+ T­CM:CD4 composition. Five patients received a product manufactured using a modified strategy either due to low blood lymphocyte counts (n = 3) or due to failure to propagate T cells in culture (n = 2). CD8+ TCM and CD4+ T cells have been isolated from 12 additional patients and cryopreserved for therapy. Patients have been treated at all three dose levels without acute infusional toxicity. Severe cytokine release syndrome (sCRS) consisting of fever, hypotension, and reversible neurotoxicity associated with elevated serum IFN-γ and IL-6 was only observed in ALL patients with a high tumor burden. One ALL patient treated at the highest cell dose died of complications associated with sCRS. None of the NHL patients had sCRS. Of patients who are >6 weeks after CD19 CAR T cell therapy, best responses included complete (n=1) or partial (n=5) remission in 6/9 patients with NHL and complete remission in 5/7 patients with ALL. Both CD4+ and CD8+ CAR-T cells expanded in vivo and could be detected in blood, marrow and CSF. The peak level and duration of persistence of both CD4+ and CD8+ EGFRt+ T cells were associated with clinical response. TCRBV gene sequencing of flow sorted CD4+ and CD8+ EGFRt+CAR T cells from 2 patients showed that proliferating CAR T cells were polyclonal. A subset of NHL patients in whom CAR T cells became undetectable developed a T cell immune response to sequences in the murine CD19-specific scFv component of the CAR transgene. CONCLUSION: Adoptive immunotherapy with CD19 CAR T cells of defined subset composition is feasible and safe in a majority of heavily pretreated patients with refractory B cell malignancies and has potent anti-tumor activity. Persistence of CAR-T cells may be limited in some patients by transgene product immunogenicity. Data from this ongoing clinical trial will be updated at the meeting. Disclosures Turtle: Juno Therapeutics: Research Funding. Berger:Juno Therapeutics: Patents & Royalties. Hudecek:Juno Therapeutics: Patents & Royalties. Jensen:Juno: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Riddell:Juno Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Maloney:Juno Therapeutics: Research Funding.

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