451 Combining Bempegaldesleukin (CD122-preferential IL-2 pathway agonist) and NKTR-262 (TLR7/8 agonist) pairs local innate activation with systemic CD8+ T cell expansion to enhance anti-tumor immunity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A478-A478
Author(s):  
Annah Rolig ◽  
Daniel Rose ◽  
Saul Kivimae ◽  
Werner Rubas ◽  
William Redmond
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Cd8 T Cells ◽  
Cell Expansion ◽  
Nk Cell ◽  
Tumor Regression ◽  
Cell Activity ◽  
Cd8 T Cell ◽  
Post Treatment

BackgroundPreviously, we demonstrated that radiation therapy (RT) combined with Bempegaldesleukin (BEMPEG;NKTR-214), a first-in-class CD122-preferential IL-2 pathway agonist, led to enhanced anti-tumor efficacy through a T cell-dependent mechanism. However, we observed only modest systemic responses to BEMPEG/RT across several murine tumor models. Therefore, we explored alternative approaches to improve systemic tumor-specific immunity. We evaluated whether intratumoral NKTR-262, a polymer-modified toll-like receptor (TLR) 7/8 agonist, combined with systemic BEMPEG treatment resulted in improved tumor-specific immunity and survival compared to BEMPEG combined with RT. We hypothesized that BEMPEG/NKTR-262 immunotherapy would promote synergistic activation of local immunostimulatory innate immune responses followed by systemic adaptive immunity to significantly improve tumor regression and overall survival.MethodsTumor-bearing mice (CT26; EMT6) received BEMPEG (0.8 mg/kg; iv), RT (12 Gy x 1), and/or intratumoral NKTR-262 (0.5 mg/kg). Flow cytometry was used to evaluate CD4+ and CD8+ T cell activation status in the blood and/or tumor (7 days post-treatment) and NK cell activity in the tumor (1, 3 days post-treatment). The contribution of specific immune subsets was determined by depletion of CD4+, CD8+, or NK cells. CD8+ T cell activity was determined in vitro by tracking apoptosis in an Incucyte assay. Data are representative of 1–2 independent experiments (n=5–14/group) and statistical significance was determined by 1-way ANOVA (p-value cut-off of 0.05).ResultsBEMPEG/NKTR-262 resulted in significantly improved survival compared to BEMPEG/RT. BEMPEG/NKTR-262 efficacy was NK and CD8+ T cell-dependent, while BEMPEG/RT primarily relied on CD8+ T cells. Response to BEMPEG/NKTR-262 was characterized by a significant expansion of activated CD8+ T cells (GzmA+; Ki-67+; ICOS+; PD-1+) in the blood, which correlated with reduced tumor size (p<0.05). In the tumor, NKTR-262/BEMPEG induced higher frequencies of GzmA+ CD8+ T cells exhibiting reduced expression of suppressive molecules (PD-1+, TIM-3+), compared to BEMPEG/RT. Indeed, CD8+ T cells isolated from BEMPEG/NKTR-262-treated tumors had greater cytolytic capacity than those from BEMPEG/RT-treated mice. CD8+ T cell expansion (blood) and activity (tumor) depended upon the initial NK response, as neither occurred in the absence of NK cells. BEMPEG/NKTR-262 uniquely induced the expansion of early and high effector NK cells.ConclusionsCombining BEMPEG with NKTR-262 lead to an early and robust NK cell expansion not observed in the BEMPEG/RT combination. The improved tumor regression and survival was dependent on the NKTR-262 driven expansion of NK cells. A clinical trial of BEMPEG/NKTR-262 for patients with metastatic solid tumors is in progress (NCT03435640).

scholarly journals Role of Recipient CD8+ T Cell Exhaustion in the Rejection of Adoptively Transferred Haploidentical NK Cells

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 503-503
Author(s):  
Robin Williams ◽  
Sarah Cooley ◽  
Veronika Bachanova ◽  
Thomas A Waldmann ◽  
Bruce R. Blazar ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Cd8 T Cells ◽  
Cell Expansion ◽  
Nk Cell ◽  
Cd8 T Cell ◽  
T Cell Exhaustion ◽  
Cell Exhaustion ◽  
Refractory Aml

Natural killer (NK) cells are cytotoxic innate lymphoid cells, which play a major role in tumor surveillance. We have tested the safety and efficacy of allogeneic NK cell adoptive transfer from heathy haploidentical donors and demonstrate that in vivo expansion and persistence of the adoptively transferred NK cells at Day 14 after infusion correlates with 30-50% remission in patients with refractory AML. However, the factors that influence successful persistence of donor-derived NK cells are unclear. We hypothesized that recipient T cells play a role in the rejection of allogeneic NK cells and a correlation could exist between persistence of donor-derived NK cells and exhaustion in recipient T cells. T cell exhaustion, a well-established state of T-cell dysfunction occurring in response to chronic and continuous antigen stimulation, is well-documented in human cancer, and characterized by progressive and hierarchical loss of effector functions including sustained up-regulation and co-expression of multiple inhibitory receptors such as PD-1 and Tim-3 and altered expression of key transcription factors including the gain of Eomes and T-bet. We used samples from a phase I/II trial of CD3/CD19 depleted, IL-15-activated, haploidentical donor NK cells delivered following conditioning with cyclophosphamide (50mg/kg) and fludarabine (35 mg/m2 x 3days) in adults with chemotherapy refractory AML. Patients received donor NK cells on Day 0 followed by 10 doses of recombinant human (rh) IL-15 (2 mcg/kg/day) manufactured by the NCI and delivered SQ on Days 1-5 and 8-12. A significant proportion of patients experienced donor NK cell expansion at Day 14 (expanders), but there were some that did not (non-expanders). Therapeutic benefit has only been noted among the expanders. We examined samples from a total of 10 patients with refractory AML, 5 expanders and 5 non-expanders, along with their 10 respective donors. Cryopreserved patient PBMCs were thawed and rested overnight in RPMI-1640 with 2% FBS. The cells were stained for viability, for surface markers using antibodies against CD3, CD8, CD56, PD-1, and Tim-3, intracellularly stained for Eomes and T-bet. We evaluated CD8+ T cell expression of PD-1 and Tim-3, in expanders and non-expanders, prior to chemotherapy and at Day 14. Paired donor T cells from the non-mobilized apheresis products served as controls. Prior to chemotherapy, both patient groups had equivalently elevated expression of both PD1 and Tim-3 on CD8+ T cells. However, at Day 14, the expanders had persistence of PD-1 and Tim-3 while expression on non-expander CD8+ T cells fell to donor level (Figure 1A). Furthermore, expanders had a significantly higher proportion of CD8+ T cells that either co-expressed PD-1 and Tim-3 (p=0.017) or had a PD-1high phenotype (p=0.032) at Day 14, both of which are suggestive of an exhausted state, as opposed to an activated one (Figure 1B,C). Next, we examined Eomes and T-bet expression in recipient T cells. While generally low among healthy T cell populations, as T cells become exhausted, they gain expression of these transcription factors. We looked specifically at the expression of these transcription factors in the recipient CD8+ T cell populations with the highest likelihood of being exhausted, i.e. those co-expressing PD-1 and Tim-3 or those with the PD-1high phenotype. Eomes expression in recipient PD-1high CD8+ T cells and in PD-1+Tim-3+ CD8+ T cells at Day 14 was significantly higher (p=0.01 and p=0.04, respectively) among expanders compared to non-expanders (Figure 2A,B). Likewise, T-bet expression was greater (p=0.004) among expanders in the PD-1high population (Figure 2A). There was no difference in the T-bet expression in PD-1+Tim-3+ CD8+ T cells between groups (Figure 2B). While all patients with refractory AML receiving NK cell adoptive transfer had an elevated percentage of CD8+ T cells with an exhausted phenotype prior to therapy, only patients with donor-derived NK cell expansion had persistence of the exhausted T cell phenotype at Day 14. Thus, T cell mediated rejection is a major obstacle to overcome for successful adoptive NK cell transfer which could in part be aided by a link between recipient T cell exhaustion and expansion of NK cells. This might further suggest that IL-15 reverses T cell exhaustion among those who failed to achieve donor-derived NK cell expansion. Disclosures Miller: Fate Therapeutics: Consultancy, Research Funding; Oxis Biotech: Consultancy, Other: SAB.

scholarly journals DNAM-1 promotes activation of cytotoxic lymphocytes by nonprofessional antigen-presenting cells and tumors

2008 ◽  
Vol 205 (13) ◽  
pp. 2965-2973 ◽  
Author(s):  
Susan Gilfillan ◽  
Christopher J. Chan ◽  
Marina Cella ◽  
Nicole M. Haynes ◽  
Aaron S. Rapaport ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Adhesion Molecules ◽  
Cd8 T Cells ◽  
Nk Cell ◽  
Cd8 T Cell ◽  
Antigen Presenting

Natural killer (NK) cells and CD8 T cells require adhesion molecules for migration, activation, expansion, differentiation, and effector functions. DNAX accessory molecule 1 (DNAM-1), an adhesion molecule belonging to the immunoglobulin superfamily, promotes many of these functions in vitro. However, because NK cells and CD8 T cells express multiple adhesion molecules, it is unclear whether DNAM-1 has a unique function or is effectively redundant in vivo. To address this question, we generated mice lacking DNAM-1 and evaluated DNAM-1–deficient CD8 T cell and NK cell function in vitro and in vivo. Our results demonstrate that CD8 T cells require DNAM-1 for co-stimulation when recognizing antigen presented by nonprofessional antigen-presenting cells; in contrast, DNAM-1 is dispensable when dendritic cells present the antigen. Similarly, NK cells require DNAM-1 for the elimination of tumor cells that are comparatively resistant to NK cell–mediated cytotoxicity caused by the paucity of other NK cell–activating ligands. We conclude that DNAM-1 serves to extend the range of target cells that can activate CD8 T cell and NK cells and, hence, may be essential for immunosurveillance against tumors and/or viruses that evade recognition by other activating or accessory molecules.

scholarly journals Synergy of IL-21 and IL-15 in regulating CD8+ T cell expansion and function

2005 ◽  
Vol 201 (1) ◽  
pp. 139-148 ◽  
Author(s):  
Rong Zeng ◽  
Rosanne Spolski ◽  
Steven E. Finkelstein ◽  
SangKon Oh ◽  
Panu E. Kovanen ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Cd8 T Cells ◽  
Cell Expansion ◽  
Tumor Regression ◽  
Severe Combined Immunodeficiency ◽  
Cd8 T Cell ◽  
T Cell Expansion

Interleukin (IL)-21 is the most recently recognized of the cytokines that share the common cytokine receptor γ chain (γc), which is mutated in humans with X-linked severe combined immunodeficiency. We now report that IL-21 synergistically acts with IL-15 to potently promote the proliferation of both memory (CD44high) and naive (CD44low) phenotype CD8+ T cells and augment interferon-γ production in vitro. IL-21 also cooperated, albeit more weakly, with IL-7, but not with IL-2. Correspondingly, the expansion and cytotoxicity of CD8+ T cells were impaired in IL-21R−/− mice. Moreover, in vivo administration of IL-21 in combination with IL-15 boosted antigen-specific CD8+ T cell numbers and resulted in a cooperative effect on tumor regression, with apparent cures of large, established B16 melanomas. Thus, our studies reveal that IL-21 potently regulates CD8+ T cell expansion and effector function, primarily in a synergistic context with IL-15.

scholarly journals NK cells negatively regulate CD8 T cells to promote immune exhaustion and chronic Toxoplasma gondii infection

2019 ◽  
Author(s):  
Daria L. Ivanova ◽  
Ryan Krempels ◽  
Stephen L. Denton ◽  
Kevin D. Fettel ◽  
Giandor M. Saltz ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Toxoplasma Gondii ◽  
Nk Cells ◽  
Cell Population ◽  
Cd8 T Cells ◽  
Nk Cell ◽  
Chronic Phase ◽  
Cd8 T Cell ◽  
Cell Compartment

AbstractNK cells regulate CD4+ and CD8+ T cells in acute viral infection, vaccination and the tumor microenvironment. NK cells also become exhausted in chronic activation settings. The mechanisms causing these ILC responses and their impact on adaptive immunity are unclear. CD8+ T cell exhaustion develops during chronic Toxoplasma gondii (T. gondii) infection resulting in parasite reactivation and death. How chronic T. gondii infection impacts the NK cell compartment is not known. We demonstrate that NK cells do not exhibit hallmarks of exhaustion. Their numbers are stable and they do not express high PD1 or LAG3. NK cell depletion with anti-NK1.1 is therapeutic and rescues chronic T. gondii infected mice from CD8+ T cell exhaustion dependent death, increases survival after lethal secondary challenge and reduces parasite reactivation. Anti-NK1.1 treatment increased polyfunctional CD8+ T cell responses in spleen and brain and reduced CD8+ T cell apoptosis. Chronic T. gondii infection promotes the development of a modified NK cell compartment, which does not exhibit normal NK cell behavior. This splenic CD49a-CD49b+NKp46+ NK cell population develops during the early chronic phase of infection and increases through the late chronic phase of infection. They are Ly49 and TRAIL negative and are enriched for expression of CD94/NKG2A and KLRG1. They do not produce IFNγ, are IL-10 negative, do not increase PDL1 expression, but do increase CD107a on their surface. They are also absent from brain. Based on the NK cell receptor phenotype we observed NKp46 and CD94-NKG2A cognate ligands were measured. Activating NKp46 (NCR1-ligand) ligand increased and NKG2A ligand Qa-1b expression was reduced. Blockade of NKp46 also rescued the chronically infected mice from death. Immunization with a single dose non-persistent 100% protective T. gondii vaccination did not induce this cell population in the spleen, suggesting persistent infection is essential for their development. We hypothesize chronic T. gondii infection induces an NKp46 dependent modified NK cell population that reduces functional CD8+ T cells to promote persistent parasite infection in the brain. NK cell targeted therapies could enhance immunity in people with chronic infections, chronic inflammation and cancer.

scholarly journals A DNA-based cancer vaccine enhances lymphocyte cross talk by engaging the NKG2D receptor

Blood ◽  
2006 ◽  
Vol 107 (8) ◽  
pp. 3251-3257 ◽  
Author(s):  
He Zhou ◽  
Yunping Luo ◽  
Charles D. Kaplan ◽  
Jörg A. Krüger ◽  
Sung-Hyung Lee ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Dna Vaccine ◽  
Cross Talk ◽  
Cd8 T Cells ◽  
Nk Cell ◽  
Cell Activity ◽  
Nk Cell Activity ◽  
Nkg2d Receptor

Abstract The NKG2D receptor is a stimulatory receptor expressed on NK cells and activated CD8 T cells. We previously demonstrated that engaging the NKG2D receptor markedly improved the efficacy of a survivin-based DNA vaccine. The combination vaccine, encoding both the NKG2D ligand H60 and survivin, activates innate and adaptive antitumor immunity and results in better protection against tumors of different origin and NKG2D expression levels. Here we demonstrate that the enhanced vaccine efficacy is in part attributable to increased cross talk between lymphocytes. Depletion of CD8 T cells during priming reduces the vaccine-induced activation of dendritic cells (DCs) and NK cell activity. Depletion of NK cells during priming leads to reduced DC activation and CTL activity. However, depletion of CD4 T cells results in the activation of DCs, NK cells, and CD8 T cells and enhances NK cell activity. The pH60/Survivin vaccine also increases DCs and NK cells but decreases CD4 T cell homing to Peyer patches, presumably as a result of changes in the homing receptor profile. Thus, by preferentially activating and attracting positive regulators and reducing negative regulators in Peyer patches, this dual-function DNA vaccine induces a microenvironment more suitable for NK cell activation and T cell priming.

scholarly journals Anti-tumor effects of RTX-240: an engineered red blood cell expressing 4-1BB ligand and interleukin-15

2021 ◽  
Author(s):  
Shannon L. McArdel ◽  
Anne-Sophie Dugast ◽  
Maegan E. Hoover ◽  
Arjun Bollampalli ◽  
Enping Hong ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Blood Cell ◽  
Nk Cells ◽  
Red Blood Cell ◽  
Safety Profile ◽  
Nk Cell ◽  
Cell Activity ◽  
In Vivo Studies

AbstractRecombinant agonists that activate co-stimulatory and cytokine receptors have shown limited clinical anticancer utility, potentially due to narrow therapeutic windows, the need for coordinated activation of co-stimulatory and cytokine pathways and the failure of agonistic antibodies to recapitulate signaling by endogenous ligands. RTX-240 is a genetically engineered red blood cell expressing 4-1BBL and IL-15/IL-15Rα fusion (IL-15TP). RTX-240 is designed to potently and simultaneously stimulate the 4-1BB and IL-15 pathways, thereby activating and expanding T cells and NK cells, while potentially offering an improved safety profile through restricted biodistribution. We assessed the ability of RTX-240 to expand and activate T cells and NK cells and evaluated the in vivo efficacy, pharmacodynamics and tolerability using murine models. Treatment of PBMCs with RTX-240 induced T cell and NK cell activation and proliferation. In vivo studies using mRBC-240, a mouse surrogate for RTX-240, revealed biodistribution predominantly to the red pulp of the spleen, leading to CD8 + T cell and NK cell expansion. mRBC-240 was efficacious in a B16-F10 melanoma model and led to increased NK cell infiltration into the lungs. mRBC-240 significantly inhibited CT26 tumor growth, in association with an increase in tumor-infiltrating proliferating and cytotoxic CD8 + T cells. mRBC-240 was tolerated and showed no evidence of hepatic injury at the highest feasible dose, compared with a 4-1BB agonistic antibody. RTX-240 promotes T cell and NK cell activity in preclinical models and shows efficacy and an improved safety profile. Based on these data, RTX-240 is now being evaluated in a clinical trial.

scholarly journals 584 Powerful synergistic effects of a STING agonist and the IL-2 superkine, H9, in eliciting NK and T cell responses against MHC I- and MHC I+ tumors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A614-A614
Author(s):  
Natalie Wolf ◽  
Cristina Blaj ◽  
Lora Picton ◽  
Gail Snyder ◽  
Li Zhang ◽  
...  
Keyword(s):  
T Cell ◽  
Combination Therapy ◽  
Nk Cells ◽  
Nk Cell ◽  
Tumor Regression ◽  
T Cell Responses ◽  
Cd8 T Cell ◽  
Mhc I ◽  
Therapy Regimen ◽  
Cell Responses

BackgroundMost current cancer immunotherapies are based on mobilizing CD8 T cell responses. However, many types of tumors evade CD8 T cell recognition by displaying few or no antigens, or losing expression of MHC I. These considerations underlie the need for complementary therapies that mobilize other antitumor effector cells, such as NK cells, which preferentially kill MHC I-deficient cells. Cyclic dinucleotides (CDNs) activate the cGAS-STING pathway of the innate immune system and are candidates as immunotherapy agents. Intratumoral CDN injections induce type I IFNs and other mediators that amplify the CD8 T cell response and induce tumor regression [1]. CDN therapy also induces long-term tumor regressions in some MHC I-deficient tumor models, mediated primarily by NK cells [2].MethodsTo extend the efficacy of CDN therapy, we combined the IL-2 superkine, H9, or half-life extended H9, with CDNs to target and activate NK cells in the tumor microenvironment and prevent or delay the onset of NK cell desensitization [3,4]. In these studies, we utilized B16-F10 and MC38 tumor cells lacking B2m to examine effects of the combination therapy on MHC I-deficient tumor growth as well as to examine the activation of NK cells by flow cytometry and cytotoxicity assays. We also utilized B16-F10 WT and the spontaneous tumor model, MCA, to assess the effect of the combination therapy on MHC I+ tumors.ResultsHere we show that H9 synergized with CDN therapy to mobilize much more powerful antitumor responses against MHC I-deficient tumors than CDN alone. The responses were mediated by NK cells and in some cases CD4 T cells, and were accompanied by increased recruitment to and sustained activation of NK cells in the tumor. This combination therapy regimen activated NK cells systemically, as shown by antitumor effects distant from the site of CDN injection and enhanced cytolytic activity of splenic NK cells against tumor cell targets ex vivo. Finally, the same combination therapy regimen synergistically mobilized powerful CD8 T cell responses in the case of MHC I+ tumor cells, suggesting the generality of the approach. The approach was effective against primary sarcomas, as well, especially when combined with checkpoint therapy, leading to tumor regressions and long-term survival of many mice with MCA-induced sarcoma.ConclusionsOverall, our work demonstrates the impact of a novel combination therapy in mobilizing powerful NK and T cell-mediated antitumor activity, providing important justification for evaluating this approach for treating cancers that are refractory to available treatment options.ReferencesCorrales, L., Glickman, L.H., McWhirter, S.M., Kanne, D.B., Sivick, K.E., Katibah, G.E., Woo, S.R., Lemmens, E., Banda, T., Leong, J.J., et al. (2015). Direct Activation of STING in the Tumor Microenvironment Leads to Potent and Systemic Tumor Regression and Immunity. Cell Rep 11, 1018–1030.Nicolai, C.J., Wolf, N., Chang, I.C., Kirn, G., Marcus, A., Ndubaku, C.O., McWhirter, S.M., and Raulet, D.H. (2020). NK cells mediate clearance of CD8(+) T cell-resistant tumors in response to STING agonists. Science immunology 5, eaaz2738.Levin, A.M., Bates, D.L., Ring, A.M., Krieg, C., Lin, J.T., Su, L., Moraga, I., Raeber, M.E., Bowman, G.R., Novick, P., et al. (2012). Exploiting a natural conformational switch to engineer an interleukin-2 ‘superkine’. Nature 484, 529–533.Ardolino, M., Azimi, C.S., Iannello, A., Trevino, T.N., Horan, L., Zhang, L., Deng, W., Ring, A.M., Fischer, S., Garcia, K.C., and Raulet, D.H. (2014). Cytokine therapy reverses NK cell anergy in MHC-deficient tumors. J Clin Invest 124, 4781–4794.

scholarly journals Transient and persistent effects of IL-15 on lymphocyte homeostasis in nonhuman primates

Blood ◽  
2010 ◽  
Vol 116 (17) ◽  
pp. 3238-3248 ◽  
Author(s):  
Enrico Lugli ◽  
Carolyn K. Goldman ◽  
Liyanage P. Perera ◽  
Jeremy Smedley ◽  
Rhonda Pung ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Cell Activation ◽  
Nk Cell ◽  
The Body ◽  
Effector Memory ◽  
Memory Cd8 T Cells

Abstract Interleukin-15 (IL-15) is a cytokine with potential therapeutic application in individuals with cancer or immunodeficiency to promote natural killer (NK)– and T-cell activation and proliferation or in vaccination protocols to generate long-lived memory T cells. Here we report that 10-50 μg/kg IL-15 administered intravenously daily for 12 days to rhesus macaques has both short- and long-lasting effects on T-cell homeostasis. Peripheral blood lymphopenia preceded a dramatic expansion of NK cells and memory CD8 T cells in the circulation, particularly a 4-fold expansion of central memory CD8 T cells and a 6-fold expansion of effector memory CD8 T cells. This expansion is a consequence of their activation in multiple tissues. A concomitant inverted CD4/CD8 T-cell ratio was observed throughout the body at day 13, a result of preferential CD8 expansion. Expanded T- and NK-cell populations declined in the blood soon after IL-15 was stopped, suggesting migration to extralymphoid sites. By day 48, homeostasis appears restored throughout the body, with the exception of the maintenance of an inverted CD4/CD8 ratio in lymph nodes. Thus, IL-15 generates a dramatic expansion of short-lived memory CD8 T cells and NK cells in immunocompetent macaques and has long-term effects on the balance of CD4+ and CD8+ T cells.

T Cell Responses during Long-Term Continuous Infusion of MT103 (MEDI-538; Anti-CD19 BiTE) in Patients with Relapsed B-NHL: Data from Dose-Escalation Study MT103-104.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2725-2725 ◽  
Author(s):  
Matthias Klinger ◽  
Peter Kufer ◽  
Petra Kirchinger ◽  
Ralf Lutterbüse ◽  
Eugen Leo ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
T Cell Activation ◽  
Cd8 T Cells ◽  
Dose Escalation ◽  
Cell Expansion ◽  
Cell Activation ◽  
Cd8 T Cell ◽  
Cell Counts ◽  
T Cell Expansion

Abstract MT103 (MEDI-538) is a bispecific single-chain antibody construct directed at CD3 on human T cells and CD19 on human B lymphoma and normal B cells. Transient linkage of B and T cells by MT103 provides T cells with a T cell receptor (TCR)-like signal leading to redirected lysis of B cell targets without apparent need of costimulation and inducing T cells to proliferate, secrete cytokines and upregulate surface activation markers. TCR-like signalling by MT103 is strictly dependent on the presence of target cells. Redirected lysis of CD19-positive cells by MT103 is seen at low picomolar concentrations and at low effector-to-target ratios. The in-vivo half-life of MT103 is approximately two hours. In the ongoing dose escalation study MT103-104, patients with relapsed B-NHL have so far received continuous infusion of MT103 at maintenance flow-rates of 0.5, 1.5, 5 and 15 μg/m2/24h for 4 or 8 weeks following a 3+3 dose escalation design. Serum concentrations of MT103 remained constant over the entire treatment period at a level depending on the respective maintenance flow-rate. Depletion of circulating B (lymphoma) cells could be observed more frequently with increasing dose levels (DL) from DL1 to DL3, and in all evaluable patients at DL4. Three of six evaluable patients at DL4 showed clinical responses (2 PR, 1 CR) according to standardized Cheson criteria, but no patient of DL1-3. The time courses of absolute CD4 and CD8 T cell counts in peripheral blood were determined by flow cytometry. CD8 T lymphocytes were further subdivided for analysis into naïve T cells, TCM (central memory T cells), TEM (effector memory T cells) and TEMRA (non-proliferating terminally differentiated CTL), and CD4 T lymphocytes into naïve T cells, TCM and TEM. Activation of CD4 and CD8 T cell subsets was determined by measuring upregulation of CD69, CD25 and HLA-DR. Serum levels of cytokines were determined as additional biomarkers for T cell activation. In 50% of patients at DL1 to DL3, CD4 and CD8 T cell counts increased during the course of treatment - over pre-treatment levels. The TEM subset from both CD4 and CD8 T cells accounted for most of the observed increases, while the naïve T cell subsets showed no increase but also no signs of apoptosis. The non-proliferative TEMRA subset of CD8 T cells also remained unchanged in most patients. This indicated that the selective increase of proliferation-competent TEM subsets was attributed to MT103-induced T cell proliferation. At DL4, all evaluable patients showed signs of T cell expansion after 2 weeks of MT103 infusion, which was most pronounced in those who developed a partial or complete remission. The increase of CD8 T cell counts was more pronounced than that of CD4 T cells. T cell expansion was accompanied by upregulation of T cell activation markers as well as by increases in serum concentrations of cytokines like IFN-γ. T cell expansion and activation reverted in all cases when the infusion of MT103 was stopped. In summary, MT103 induced a reversible secondary T cell response involving T cell activation and proliferation as well as T cell cytotoxicity against circulating B cells and lymphoma tissue. The dose-dependent T cell expansion observed during long-term infusion of MT103, particularly within the cytotoxic TEM subset of CD8 T cells, appears to play a key role for clinical activity.

Natural Killer Cell Immune Reconstitution Predicts Outcomes for Patients with Chronic Lymphocytic Leukemia Undergoing Allogeneic Stem Cell Transplantation

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3300-3300
Author(s):  
Don Benson ◽  
Leslie Andritsos ◽  
Mehdi Hamadani ◽  
Thomas Lin ◽  
Joseph Flynn ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Nk Cells ◽  
Cd8 T Cells ◽  
Immune Reconstitution ◽  
Nk Cell ◽  
Disease Status ◽  
Lymphocytic Leukemia ◽  
T Cell Subsets ◽  
Cell Recovery

Abstract Introduction: Chronic lymphocytic leukemia (CLL), the most common form of leukemia in the Western hemisphere, is associated with severe innate, adaptive and humoral immune dysregulation. CLL remains essentially incurable, with the potential exception of allogeneic stem cell transplantation (ASCT). Natural killer (NK) cells are CD56(+), CD3(−) large granular lymphocytes that comprise a key cellular subset of the innate immune system. Preliminary in vitro data suggest an NK cell versus CLL effect exists, similar to that observed in acute myeloid leukemia (AML) and other blood cancers. Novel immune therapies for CLL (e.g., rituximab, alemtuzumab) likely exert anti-tumor effect, in part, through NK cells, in fact. Although NK cells contribute to the graft-versus-tumor effect following ASCT for other blood cancers, little is known regarding the potential role NK cells may play in the clinical allogeneic transplant setting for CLL. Herein, we provide, to our knowledge, the first report regarding NK cell immune reconstitution following ASCT for CLL. Methods: 27 CLL patients underwent reduced intensity conditioning (RIC) with ASCT. Median age was 52 years (43–69), median number of prior therapies was 3 (2–11). 55% had chemotherapy-refractory disease, and 55% had “high-risk” cytogenetics by FISH (deletion 17p or 11q22-23 abnormality). 14 patients had sibling donors, 15 had volunteerunrelated donors. Conditioning regimens included Fludarabine/TBI/Alemtuzumab (n=8), Fludarabine/Busulfan with (n=9) or without ATG (n=6), and Fludarabine/Cyclophosphamide (n=4). GVHD prophylaxis consisted of tacrolimus/MMF (n=8) or tacrolimus/methotrexate (n=19). Patients underwent bone marrow assessment prior to day +75 following ASCT. Marrow was studied for engraftment, donor chimerism, and disease status as well as lymphoid immune reconstitution by percentage of total lymphocytes and absolute lymphocyte counts by multi-color flow cytometry. Results: NK cell immune reconstitution was predicted by disease status at transplantation. Patients in complete or partial remission at the time of ASCT had more robust NK cell recovery (mean = 45% of total lymphocytes +/− SEM 5%) as compared to patients entering transplant with refractory disease (16% +/− 1, p < 0.01). No differences were observed in CD4(+) or CD8(+) T cells and no lymphocyte subset recovery was associated with CD34(+) or CD3(+) cell dosage. Achieving complete donor chimerism by day +60 was associated with robust NK cell recovery (55% +/− 1 versus 7% +/−1, p = 0.02), recovery of CD4 and CD8 T cells was not associated with chimerism status, however. Patients who went onto exhibit a complete response to ASCT had greater early NK cell reconstitution (31% +/− 3) as compared to those who had no response (8% +/− 1, p = 0.01). No differences in T cell subsets were associated with response. Patients who ultimately achieved complete remission following transplant had a lower CLL:NK cell ratio in marrow (0.35 +/− 0.07) than those who did not (8.1 +/− 1, p = 0.01). However, differences in CLL:CD4(+) and CLL:CD8(+) T cells were not predictive of response. Trends to improvement in progression free survival and overall survival were observed for patients with NK cell reconstitution above the median for the group as compared to those below; no such trends were observed regarding T cell subsets. Greater NK cell reconstitution trended towards ultimate eradication of minimal residual disease following ASCT, but no such trends were observed for T cell subsets. Conclusions: Early NK cell recovery predicts survival following autologous and allogeneic SCT in a number of hematologic malignancies; however, little is known regarding this phenomenon in CLL. To our knowledge, these are the first findings to implicate a potentially important therapeutic role for early NK cell compartment recovery in CLL following ASCT. Further research into restoring and augmenting NK cell function following RIC/ASCT for CLL is warranted.

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