scholarly journals CD137 stimulation enhances the antilymphoma activity of anti-CD20 antibodies

Blood ◽  
2011 ◽  
Vol 117 (8) ◽  
pp. 2423-2432 ◽  
Author(s):  
Holbrook E. Kohrt ◽  
Roch Houot ◽  
Matthew J. Goldstein ◽  
Kipp Weiskopf ◽  
Ash A. Alizadeh ◽  
...  
Keyword(s):  
B Cell ◽  
Nk Cells ◽  
Costimulatory Molecule ◽  
Host Immune System ◽  
Sequential Administration ◽  
Dependent Cell ◽  
Human Lymphoma ◽  
Anti Cd20 ◽  
Stimulation Of

Abstract Antibody-dependent cell-mediated cytotoxicity (ADCC), which is largely mediated by natural killer (NK) cells, is thought to play an important role in the efficacy of rituximab, an anti-CD20 monoclonal antibody (mAb) used to treat patients with B-cell lymphomas. CD137 is a costimulatory molecule expressed on a variety of immune cells after activation, including NK cells. In the present study, we show that an anti-CD137 agonistic mAb enhances the antilymphoma activity of rituximab by enhancing ADCC. Human NK cells up-regulate CD137 after encountering rituximab-coated tumor B cells, and subsequent stimulation of these NK cells with anti-CD137 mAb enhances rituximab-dependent cytotoxicity against the lymphoma cells. In a syngeneic murine lymphoma model and in a xenotransplanted human lymphoma model, sequential administration of anti-CD20 mAb followed by anti-CD137 mAb had potent antilymphoma activity in vivo. These results support a novel, sequential antibody approach against B-cell malignancies by targeting first the tumor and then the host immune system.

Immunomodulation of NK Cells through 4-1BB (CD137) to Improve the Anti-Lymphoma Activity of Rituximab: Antibody-Based Anti-Lymphoma Synergy

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 422-422
Author(s):  
Holbrook E Kohrt ◽  
Roch Houot ◽  
Matthew J Goldstein ◽  
Kipp Weiskopf ◽  
Mark Chao ◽  
...  
Keyword(s):  
B Cell ◽  
Nk Cells ◽  
Nk Cell ◽  
Primary Lymphoma ◽  
Murine Lymphoma ◽  
Chromium Release ◽  
Sequential Administration ◽  
Anti Cd20 ◽  
Stimulation Of

Abstract Abstract 422 Background: Antibody-dependent cell-mediated cytotoxicity (ADCC), largely mediated by natural killer (NK) cells, is thought to play an important role in the efficacy of rituximab, an anti-CD20 monoclonal antibody (mAb) used to treat patients with B cell lymphomas. CD137 is a costimulatory molecule expressed on a variety of immune cells following activation, including NK cells. We hypothesized that the anti-lymphoma activity of rituximab could be enhanced by stimulation of NK cells with an anti-CD137 agonistic mAb. Methods: Rituximab induced upregulation of CD137 on NK cells was assessed using lymphoma cell lines and primary lymphoma patient samples. In-vitro NK cell degranulation and cytotoxicity were assessed by CD107a mobilization and chromium release. A murine lymphoma tumor model targeted by mouse anti-mouse CD20 mAb was used to assess in-vivo synergy of anti-CD20 and anti-CD137 mAbs. Mechanism of synergy was explored by T cell, NK cell, and macrophage depletion in the immune competent mouse model. A xenotransplant model in SCID mice with disseminated, luciferase-labeled lymphoma was used to demonstrate efficacy of anti-CD137 mAb and rituximab, and sufficiency of an innate immune response. Results: NK cells in human primary lymphoma samples do not express CD137 at baseline, however these cells highly upregulate CD137 when encountering rituximab-coated tumor B cells. Rituximab-induced NK cell degranulation and cytotoxicity as measured by CD107a mobilization (p=.006) and chromium release (p=.01) are enhanced by anti-CD137 agonistic mAb. In a murine lymphoma model, anti-CD137 mAb significantly enhances anti-tumor activity of anti-CD20 mAb leading to complete tumor resolution (p<.001) and prolonged survival (p=.048). Sequential administration of anti-CD20 mAb followed by anti-CD137 mAb (p=.027) is required for the synergistic effect. In-vivo administration of anti-CD20 mAb induces upregulation of CD137 on mouse NK cells (p=0.001), allowing subsequent targeting with anti-CD137 mAb. NK cell depletion completely abrogates the therapeutic effect of anti-CD20 plus anti-CD137 mAb combination (p<.001). In a xenotransplant disseminated lymphoma model (Figure 1A), rituximab plus anti-CD137 mAb provided superior reduction in tumor burden, as quantified by bioluminescence (p=.001; Figure 1B), and prolonged overall survival (p=.013; Figure 1C). Conclusions: Our results demonstrate the synergy of anti-CD137 mAb and rituximab by stimulation of rituximab-activated NK cells with anti-CD137 mAb to enhance ADCC. These results support a novel, sequential antibody approach against B cell malignancies by targeting first the tumor and then the host immune system. Disclosures: No relevant conflicts of interest to declare.

Lenalidomide (Revlimid®) Enhances Monoclonal Antibody-Associated Anti-Tumor Activity Against Rituximab-Sensitive and Rituximab-Resistant B-Cell Lymphoma Cell Lines.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2522-2522 ◽  
Author(s):  
Nishitha Reddy ◽  
Raymond Cruz ◽  
Francisco Hernandez-Ilizaliturri ◽  
Joy Knight ◽  
Myron S. Czuczman
Keyword(s):  
B Cell ◽  
Cell Lines ◽  
Scid Mouse ◽  
In Vitro Exposure ◽  
Human Lymphoma ◽  
Scid Mouse Model ◽  
Anti Cd20 ◽  
Anti Tumor Activity

Abstract Background: Lenalidomide is a potent thalidomide analogue shown to activate both the innate and adoptive immune system, inhibit angiogenesis, and modify the tumor microenvironment. While lenalidomide has received approval by the U.S. Federal Drug Administration (FDA) for the treatment of various hematological conditions, ongoing clinical trials are addressing its role in the treatment of B-cell lymphomas. There is a dire need to develop novel well-tolerated, therapies which combine various target-specific agents such as lenalidomide and monoclonal antibodies (mAbs). We previously demonstrated that lenalidomide is capable of expanding natural killer (NK) cells in a human-lymphoma-bearing SCID mouse model and improve rituximab anti-tumor activity in vivo. Methods: In our current work we studied the effects of lenalidomide on the biological activity of a panel of mAbs against various B-cell lymphomas, utilizing various rituximab-sensitive (RSCL) and rituximab-resistant cell lines (RRCL) generated in our laboratory from Raji and RL cell lines. Functional assays including antibody-dependant cellular cytotoxicity (ADCC) and complement-mediated cytotoxicity (CMC) were performed to demonstrate changes in sensitivity to rituximab. RSCL and RRCL (1′105 cells/well) were exposed to either lenalidomide (5 μg/ml) or vehicle with or without mAb at a final concentration of 10μg/ml. The mAb panel consisted of two anti-CD20 mAbs: rituximab (Biogen IDEC, Inc.) and hA20, a humanized anti-CD20 mAb (Immunomedics, Inc.); an anti-CD80 mAb (galixumab, Biogen IDEC Inc.), and an anti-CD52 antibody (Alemtuzumab, Berlex Inc.). Changes in DNA synthesis and cell proliferation were determined at 24 and 48 hrs by [3H]-thymidine uptake. For ADCC/CMC studies, NHL cells were exposed to lenalidomide or vehicle for 24 hrs and then labeled with 51Cr prior to treatment with one of various mAbs (10 mg/ml) and peripheral blood mononuclear cells (Effector: Target ratio, 40:1) or human serum, respectively. 51Cr-release was measured and the percentage of lysis was calculated. Changes in antigen (CD20, CD80, and CD52) expression following in vitro exposure to lenalidomide were studied by multicolor flow cytometric analysis. Results: Concomitant in vitro exposure of various RSCL and RRCL cells to lenalidomide and either galixumab, hA20 or alemtuzumab for 24 hrs resulted in improved anti-tumor activity when compared to controls. In addition, pre-incubation of both RSCL and RRCL with lenalidomide rendered cells more susceptible to alemtuzumab-, hA20- and galixumab-mediated ADCC and CMC. No antigen modulation (i.e., upregulation) was observed following in vitro exposure of lenalidomide to NHL cell lines, suggesting an alternative mechanism involved in the improvement antitumor activity observed. Conclusions: Our data suggest that the augmented antitumor effect of lenalidomide is not limited to its combination with rituximab, but also that it augments the antiproliferative and biological activity of alemtuzumab, hA20 and galixumab. Furthermore, these interactions are observed even in our RRCL. Future studies will be directed towards evaluating whether similar activity will be seen in vivo using a human lymphoma-bearing SCID mouse model. (Supported by USPHS grant PO1-CA103985 from the National Cancer Institute.)

scholarly journals Activation of natural killer cells by rituximab in granulomatosis with polyangiitis

2019 ◽  
Vol 21 (1) ◽  
Author(s):  
Doris Urlaub ◽  
Shuyang Zhao ◽  
Norbert Blank ◽  
Raoul Bergner ◽  
Maren Claus ◽  
...  
Keyword(s):  
B Cells ◽  
B Cell ◽  
Nk Cells ◽  
Natural Killer ◽  
Mechanism Of Action ◽  
Granulomatosis With Polyangiitis ◽  
Color Flow ◽  
Cd20 Antibody ◽  
Anti Cd20

Abstract Objective In the last few years, anti-CD20 antibody rituximab profoundly changed the therapeutic landscape of granulomatosis with polyangiitis (GPA). Here, we investigated whether natural killer (NK) cells may play a role in rituximab’s mechanism of action in GPA. Methods B cell depletion, NK cell degranulation, and the expression of CD69 and CD16 on NK cells were measured in a series of in vitro experiments using peripheral blood mononuclear cells (PBMCs). In vivo activation of NK cells was investigated in patients receiving rituximab infusions. Cells were analyzed by seven-color flow cytometry. Results NK cells from GPA patients were activated by immobilized rituximab. Also soluble rituximab activated NK cells, provided that B cells were present. NK cells degranulated and expressed the activation marker CD69 while CD16 expression was decreased. This activation of NK cells by soluble rituximab was accompanied by a reduction of B cells. The next-generation anti-CD20 antibody obinutuzumab showed stronger effects compared to rituximab on both the reduction of B cells and the activation of NK cells. Finally, we found that rituximab led to the activation of NK cells in vivo, provided that B cells were not depleted due to prior rituximab infusions. Conclusion B cell-bound rituximab activates NK cells in GPA. While NK cells therefore participate in rituximab’s mechanism of action in humans, their potential may be more efficiently exploited, e.g., by Fc engineering of therapeutic antibodies.

An ADCC-Independent Mechanism of Rituximab-Mediated B-NHL Cells Depletion Via Sensitization to Cell Death through the Expression of TRAIL on NK Cells

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 4919-4919
Author(s):  
Mario I. Vega ◽  
Sara Huerta-Yepez ◽  
Melisa Martinez-Paniagua ◽  
Stavroula Baritaki ◽  
Benjamin Bonavida
Keyword(s):  
B Cell ◽  
Cytotoxic Activity ◽  
Nk Cells ◽  
Tumor Cells ◽  
Cell Lines ◽  
Fas Ligand ◽  
Cytotoxic Cells ◽  
Induced Apoptosis ◽  
Anti Cd20

Abstract Abstract 4919 Rituximab, a chimeric anti-CD20 mAb, has being used, alone or in combination with chemotherapy, in the treatment of patients with B-NHL and rheumatoid arthritis. It is also being tested clinically in the treatment of other B cell malignancies. The mechanisms by which the antibody depletes the B cells have been shown to be mediated via ADCC, CDC, and apoptosis. In addition, the antibody also signals the cells and modifies various survival pathways and sensitizes the resistant tumor cells to various apoptotic stimuli (Jazirehi and Bonavida, Oncogene 24:2121, 2005). The role of the host innate cytotoxic cells, such as NK cells, in cooperation with rituximab in the depletion of B-NHL cells has been poorly explored. Studies by us and others have reported that rituximab sensitizes resistant B-NHL tumor cells to both Fas ligand and TRAIL-induced apoptosis (Bonavida, Oncogene 26:3629, 2007; Daniel, D. et al., Blood 110:4037, 2007). Since NK cells express on the surface TRAIL, we hypothesized that rituximab may also sensitize the TRAIL-resistant tumor cells to NK-mediated cytotoxicity. Accordingly, we have examined various TRAIL-resistant B-NHL cell lines and used peripheral blood-derived purified human NK cells. Treatment of various B-NHL cell lines with rituximab sensitized the cells to TRAIL-induced apoptosis. The mechanism of TRAIL-induced cytotoxicity was found to be the result of TRAIL-induced inhibition of NF-κB and downstream inhibition of the DR5 transcription repressor Yin Yang 1 (YY1) as well as inhibition of anti-apoptotic gene products such as Bclxl. Treatment of various B-NHL cell lines with rituximab, unlike treatment with control IgG1, resulted in significant cytotoxicity in the presence of purified NK cells. The extent of the cytotoxic activity was a function of the E:T ratios used. We then examined the contribution of TRAIL expressed on the NK cell surface for its role in NK-mediated cytotoxicity of rituximab-pretreated B-NHL cells. We used a neutralizing TRAIL antibody that was added in the reaction mixture and demonstrated that the NK cytotoxic activity was significantly reduced compared to controls. These studies with rituximab were also confirmed with other CD20 mAbs. We are currently examining the sensitization of freshly-derived B-NHL and CLL cells that are treated with rituximab and other anti-CD20 mAbs to NK-mediated cytotoxicity for validation of the findings with cell lines. The present findings suggest that, in vivo, patients who are treated with rituximab may recruit NK and other effector cells to mediate, independently of ADCC, cytotoxicity via the TNF-family ligands (e.g. TNF-α, Fas-L, TRAIL). The studies also suggest that this B cell-depletion mechanism by NK cells may contribute to the mechanism of rituximab- mediated depletion of B-NHL cells in vivo. Noteworthy, the proposed host cytotoxic mechanism may not be functional if the therapeutic treatment consists of the combination of rituximab and immunosuppressive chemotherapeutic drugs that may lead to depletion or inactivation of host cytotoxic cells. Disclosures: No relevant conflicts of interest to declare.

Targeting B-Cell Malignancies With Anti-CD20-Interleukin-21 Fusokine

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 377-377 ◽  
Author(s):  
Shruti Bhatt ◽  
Daxing Zhu ◽  
Xiaoyu Jiang ◽  
Seung-uon Shin ◽  
John M Timmerman ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Nk Cells ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cd20 Antibody ◽  
Anti Cd20

Abstract The anti-CD20 antibody rituximab has revolutionized the treatment for B cell non-Hodgkin lymphomas (NHLs). However, rituximab has limited effectiveness as a single agent in some NHL subtypes and its clinical efficacy is compromised by acquired drug resistance. As a result, many patients still succumb to NHLs. Hence, strategies that enhance the activity of anti-CD20 antibody may improve patient outcome. Interleukin-21 (IL21), a member of the IL2 cytokine family, exerts diverse regulatory effects on natural killer (NK), T and B cells. IL21 has been reported to possess potent anti-tumor activity against a variety of cancers not expressing IL21 receptor (IL21R) through activation of the immune system and is in clinical trials for renal cell carcinoma and metastatic melanoma. We have recently reported that apart from immuno-stimulatory effects, IL21 exerts direct cytotoxicity on IL21R expressing diffuse large B cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) cell lines and primary tumors both in vitro as well in vivo (Sarosiek et al Blood 2010; Bhatt et al AACR 2013). Herein we designed a fusion protein comprising IL21 linked to the N-terminus of anti-CD20 antibody (αCD20-IL21 fusokine) to improve efficacy of its individual components and prolong IL21 half-life. We have verified the expression of full length fusion protein and demonstrated that αCD20-IL21 fusokine retained binding ability to its individual components; CD20 and IL21R, as analyzed by immunofluorescence and flow-cytometry analyses. Similar to our previous study of IL21 in DLBCL, treatment of B cell lymphoma cell lines with fusokine lead to phosphorylation of STAT1 and STAT3, upregulation of cMYC and BAX and downregulation of BCL-2 and BCL-XL, implying the activation of IL21R dependent signaling to trigger cytotoxic effects. In vitro, direct cell death induced by αCD20-IL21 fusokine in DLBCL (RCK8, WSU and Farage) and MCL (Mino, HBL2 and SP53) cell lines was markedly increased compared to its individual components (IL21 and parent αCD20-IgG1 antibody). More importantly, fusokine treatment resulted in cell death of MCL cell lines (L128, G519 and UPN1) that were found to be resistant to IL21 alone treatment. Furthermore, treatment of freshly isolated primary NHL cells with the αCD20-IL21 fusokine also exhibited a 40-50% increase in direct cell death compared to its individual components. Previous studies reported that IL21 enhances antibody-dependent cellular cytotoxicity (ADCC) of therapeutic antibodies by activation of NK cells. ADCC assays using chromium release with purified human NK cells demonstrated that ADCC induced by the parent antibody was enhanced in the presence of IL21 while IL21 alone had minimal effect on the lysis of Raji, Daudi, and Jeko1 target cells. Notably, αCD20-IL21 fusokine demonstrated increased ADCC activity in comparison to parent antibody plus IL21 in Raji, Daudi and Jeko-1 cells (p<0.001, p<0.005 and p<0.001, respectively). Similar results were obtained in primary MCL tumor cells. Consistent with this finding, fusokine treatment resulted in enhanced activation of the NK cells as assessed by CD69 upregulation and CD16 downregulation using flow-cytometry. Complement dependent cytotoxicity (CDC) of the fusokine was similar to the parent antibody and rituximab in Raji cells. Studies analyzing in vivo effects of the fusokine are in progress and will be presented at the meeting. These data strongly suggest that together with direct apoptotic potential, an anti-CD20 IL21 fusokine retains the ability to trigger indirect cell killing mediated via activation of immune effector cells. These dual effects may give remarkable advantage to the fusokine over existing anti-CD20 antibodies for the treatment of NHL tumors. Collectively, our study demonstrates that anti-tumor effects of IL21 and anti-CD20 antibodies can be enhanced by conjugation of IL21 with anti-CD20 antibody that may serve as a novel anti-lymphoma therapy. Disclosures: Rosenblatt: Seattle Genetics, Inc.: Research Funding.

Effect of stimulation of natural killer cells with an anti-CD137 mAb on the efficacy of trastuzumab, cetuximab, and rituximab.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. 2514-2514 ◽  
Author(s):  
Holbrook Edwin Kohrt ◽  
Roch Houot ◽  
Kipp Weiskopf ◽  
Matthew Goldstein ◽  
Peder Lund ◽  
...  
Keyword(s):  
Nk Cells ◽  
Head And Neck ◽  
Natural Killer ◽  
Nk Cell ◽  
Cell Depletion ◽  
Release Mechanism ◽  
Host Immune System ◽  
Sequential Administration ◽  
Anti Tumor Activity ◽  
Stimulation Of

2514 Background: Antibody-dependent cell-mediated cytotoxicity (ADCC), mediated by natural killer (NK) cells, plays an important role in the efficacy of monoclonal antibodies (mAb)s. CD137 is a costimulatory molecule expressed on immune cells following activation, including NK cells. We hypothesize that as the antitumor efficacy of mAbs is due to ADCC, their activity can be enhanced by stimulation of NK cells with an anti-CD137 agonistic mAb. Methods: Upregulation of CD137 on NK cells was assessed using CD20+lymphoma, HER2+breast, and EGFR+head and neck cell lines and primary patient samples. NK cell degranulation, cytokine release and cytotoxicity were assessed by CD107a mobilization, IFN-γ secretion, and chromium release. Mechanism of synergy was explored by cell depletion in an immune competent mouse model. Xenotransplanted models were used to demonstrate anti-tumor activity and sufficiency of an innate immune response. Results: NK cells in human primary patient samples do not express CD137 at baseline, however CD137 is highly upregulated when encountering mAb-coated tumor cells. MAb-induced NK cell degranulation and cytotoxicity are enhanced by anti-CD137 agonistic mAb. In a murine lymphoma model, anti-CD137 mAb significantly enhances anti-tumor activity of anti-CD20 mAb leading to complete tumor resolution and prolonged survival. NK cell depletion completely abrogates the therapeutic effect. In seven xenotransplant models, sequential administration of rituximab, trastuzumab or cetuximab plus anti-CD137 mAb provided superior reduction in tumor burden and prolonged overall survival. In a phase 0 biomarker study, level of CD137 expression on circulating and intratumoral NK cells was influenced by disease burden, prior treatment, FcγRIII polymorphism, and time since mAb therapy. Conclusions: Our results demonstrate the synergy of anti-CD137 mAb and a tumor-targeting mAb by stimulation of mAb-activated NK cells with anti-CD137 mAb to enhance ADCC. These results support a novel, sequential antibody approach against CD20+B cell, HER2+breast, and EGFR+head and neck malignancies by targeting first the tumor and then the host immune system.

scholarly journals The IL-15 Superagonist ALT-803 Enhances NK Cell ADCC and in Vivo Clearance of B Cell Lymphomas Directed By an Anti-CD20 Monoclonal Antibody

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 807-807 ◽  
Author(s):  
Maximillian Rosario ◽  
Bai Liu ◽  
Lin Kong ◽  
Stephanie E Schneider ◽  
Emily K Jeng ◽  
...  
Keyword(s):  
B Cell ◽  
Nk Cells ◽  
Nk Cell ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Vehicle Treatment ◽  
Anti Cd20

Abstract Anti-CD20 monoclonal antibodies (mAbs) have provided an important therapeutic passive immunotherapy approach for B cell malignancies. Typically anti-CD20 mAbs are combined with traditional chemotherapy and/or radiation therapy that have the potential for serious long term adverse complications. Novel approaches are needed to improve anti-CD20 mAb anti-lymphoma efficacy with agents that do not result in long term toxicity. ALT-803 is a super agonist IL-15 variant bound to an IL-15Ralpha – Fc fusion and represents a novel immunostimulatory agent for NK and T cells. Notably, ALT-803 exhibits extended in vivo pharmacokinetics and altered biodistribution compared to recombinant human IL-15. We hypothesized that ALT-803 would enhance anti-CD20-mAb-(rituximab) directed NK cell antibody dependent cellular cytotoxicity (ADCC) against B cell lymphomas. ALT-803 at concentrations of 0.35-35 ng/mL potentiated rituximab-triggered NK cell ADCC against the Raji (27% vs. 74%, E:T 25:1, P<0.01) and Daudi (39% vs. 84%, E:T 2:1, P<0.05) B cell lymphoma lines in vitro. Moreover, the activation of NK cells with ALT-803 significantly increased ADCC against primary human follicular lymphoma cells in vitro (11% vs. 33% at a 2.5:1 E:T ratio, P<0.001, N=5 primary follicular lymphomas, N=15 NK cell donors). One mechanism whereby ALT-803 may be modulating human NK cells is via the induction of cytotoxic effector molecules. After 24-48 hour in vitro activation with ALT-803 (0.35-350 ng/mL) an increased expression of granzyme B and perforin were observed in primary human NK cells (P<0.05). The effectiveness of ALT-803 enhancement of NK cell ADCC against B cell lymphoma cell lines was assessed with two in vivo mouse models. First, Daudi cells were engrafted into SCID mice (that have an intact NK cell compartment), and groups were treated with vehicle, rituximab (10 mg/kg), ALT-803 (0.2 mg/kg), or ALT-803+rituximab at day 15 and 18, and assessed for lymphoma percentages in the bone marrow at day 22. Mice treated with ALT-803+rituximab had significantly reduced Daudi B cell burden, compared to rituximab, ALT-803, or vehicle treatment (vehicle versus ALT-803+rituximab, 38% vs. 5%, P<0.01). At doses of 0.2-0.02 mg/kg the effect of ALT-803 on rituximab mediated lymphoma clearance was demonstrated (P<0.02 compared to vehicle treatment). Further, the survival of mice treated with ALT-803+rituximab was significantly longer compared vehicle control, rituximab alone, and ALT-803 alone groups (see KM survival curves, Figure, P<0.05). In our second in vivo model, malignant Raji B cells expressing luciferase were injected into immunodeficient NOD-SCID-gamma-c-/- (NSG) mice (100,000/mouse, day 0) followed by primary human NK cells (4 million / mouse, day 3), and treated (initiated on day 3) with vehicle, ALT-803 (0.05 mg/kg q3-4 days), rituximab (10 mg/kg day 3), or ALT-803+rituximab. At day 16, ALT-803+rituximab exhibited a significant reduction in Raji signal compared to the control groups (P<0.05). These results were confirmed in a second approach where an increased Raji cell numbers were engrafted (1 million / mouse, day 0), primary human NK cells (4 million / mouse) were infused on day 3, and groups of mice were treated with rituximab (5 mg/kg) or ALT-803 (0.2 mg/kg q3-4 days)+rituximab (mean photons per second at day 34, 3.8x109 versus 3.1x108, respectively, P<0.05). ALT-803 was well tolerated at all of the administered dose levels in combination with rituximab. Thus, ALT-803 represents an effective immunostimulatory agent that augments NK cell cytotoxic potential and ADCC against malignant follicular lymphoma and B cell lines in vitro, and significantly increases rituximab-directed clearance of B cell lymphoma by NK cells in two in vivo models. Based on these findings, a phase 1/2 clinical trial of ALT-803 plus rituximab is planned for patients with relapsed/refractory indolent non-Hodgkin lymphomas. Figure 1 Figure 1. Disclosures Liu: Altor BioScience Corporation: Employment. Kong:Altor BioScience Corporation: Employment. Jeng:Altor BioScience Corporation: Employment. Rhode:Altor BioScience Corporation: Employment. Wong:Altor BioScience Corporation: Employment.

562 SO-C101 induces NK cell cytotoxicity and potentiates antibody-dependent cell cytotoxicity and anti-tumor activity

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A596-A596
Author(s):  
Zuzana Antosova ◽  
Nada Podzimkova ◽  
Marketa Jiratova ◽  
Eva Nedvedova ◽  
Guy de Martynoff ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Nk Cells ◽  
Nk Cell ◽  
Therapeutic Antibodies ◽  
Cell Cytotoxicity ◽  
Sequential Administration ◽  
Dependent Cell ◽  
Anti Tumor Activity

BackgroundSO-C101 is a superagonist fusion protein of interleukin (IL)-15 and the IL-15 receptor α (IL-15Rα) sushi+ domain, representing a promising clinical candidate for the treatment of cancer. SO-C101 specifically stimulates natural killer (NK) cells and memory CD8+ T cells with no significant expansion and activation of regulatory T cell compartment.MethodsHuman NK cell proliferation, the expression of NK cell receptors and ADCC activity of human PBMC after stimulation with SO-C101 in vitro in combination with monoclonal antibodies were detected by flow cytometry. The anti-tumor efficacy of SO-C101 in combination with Daratumumab was assessed in a multiple myeloma SCID xenograft mouse model in vivo.ResultsIn this study, we show that SO-C101 induced proliferation and expansion of both major subsets of human NK cells, CD56brightCD16- and CD56dimCD16+. Furthermore, SO-C101 induced expression of the cytotoxic receptors NKp30 and NKG2D whereas no upregulation of the inhibitory receptors CD158a, CD158b and NKG2A was detected. Both NK cell subsets activated by SO-C101 exhibited cytotoxicity towards cancer cells in vitro. Using human PBMCs, we show that SO-C101 potentiated killing of tumor cells induced by several clinically approved therapeutic monoclonal antibodies such as Cetuximab, Daratumumab and Obinutuzumab in vitro. SO-C101 and Daratumumab monotherapy treatment inhibited tumor growth in vivo, however, their combination showed the strongest anti-tumor efficacy. Specifically, sequential administration of Daratumumab, followed by SO-C101 promoted complete tumor regression, compared to partial anti-tumor responses induced by the respective monotherapies.ConclusionsSO-C101 augments the anti-tumor activity of therapeutic antibodies by increasing NK cells mediated antibody-dependent cell cytotoxicity. These results support the evaluation of SO-C101 in combination with monoclonal therapeutic antibodies in clinical studies.Ethics ApprovalThe anti-tumor efficacy studies in mice were approved by the internal ethics board of the respective contract research organization (CRO).

scholarly journals Imaging the mechanisms of anti-CD20 therapy in vivo uncovers spatiotemporal bottlenecks in antibody-dependent phagocytosis

2021 ◽  
Vol 7 (8) ◽  
pp. eabd6167
Author(s):  
Capucine L. Grandjean ◽  
Zacarias Garcia ◽  
Fabrice Lemaître ◽  
Béatrice Bréart ◽  
Philippe Bousso
Keyword(s):  
B Cell ◽  
Cell Lymphoma ◽  
Critical Path ◽  
B Cell Lymphoma ◽  
Antibody Dependent Cellular Cytotoxicity ◽  
Fluorescent Reporter ◽  
Cd20 Antibody ◽  
Anti Cd20 ◽  
Partial Depletion

Anti-CD20 antibody (mAb) represents an effective strategy for the treatment of B cell malignancies, possibly involving complement activity, antibody-dependent cellular cytotoxicity and phagocytosis (ADP). While ADP by Kupffer cells deplete circulating tumors, mechanisms targeting non-circulating tumors remain unclear. Using intravital imaging in a model of B cell lymphoma, we establish here the dominance and limitations of ADP in the bone marrow (BM). We found that tumor cells were stably residing in the BM with little evidence for recirculation. To elucidate the mechanism of depletion, we designed a dual fluorescent reporter to visualize phagocytosis and apoptosis. ADP by BM-associated macrophages was the primary mode of tumor elimination but was no longer active after one hour, resulting in partial depletion. Moreover, macrophages were present at low density in tumor-rich regions, targeting only neighboring tumors. Overcoming spatiotemporal bottlenecks in tumor-targeting Ab therapy thus represents a critical path towards the design of optimized therapies.

Unique Toxicities and Resistance Mechanisms Associated with Monoclonal Antibody Therapy

Hematology ◽  
2005 ◽  
Vol 2005 (1) ◽  
pp. 329-334 ◽  
Author(s):  
Jonathan W. Friedberg
Keyword(s):  
Follicular Lymphoma ◽  
Single Agent ◽  
Antibody Therapy ◽  
Resistance Mechanisms ◽  
Complement Dependent Cytotoxicity ◽  
Dependent Cell ◽  
Impact On Treatment ◽  
Anti Cd20 ◽  
In Vivo Cytotoxicity

Abstract Anti-CD20 therapy has had a truly dramatic impact on treatment and outcome of patients with follicular lymphoma. Unfortunately, the majority of responses to single-agent rituximab are incomplete, and all patients with follicular lymphoma will experience disease progression at some point following rituximab therapy. Rituximab has multiple mechanisms of inducing in vivo cytotoxicity, including antibody-dependent cell-mediated cytotoxicity, complement-dependent cytotoxicity, direct apoptotic signaling, and possible vaccinal effects. The cellular microenvironment within follicular lymphoma has a profound impact on which mechanism is dominant, and confers resistance in many situations. Both tumor-associated and host-associated factors also contribute to rituximab resistance. There are multiple potential approaches to overcoming rituximab resistance, including rational biologic combination immunotherapy, engineered antibodies, and radioimmunoconjugates. Improved ability to overcome resistance will require further elucidation of critical signaling pathways involved in rituximab induced cytotoxicity and a comprehensive understanding of interactions between its multiple mechanisms of action.

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