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Eldesouki RE, Wu C, Saleh FM, Mohammed EAM, Younes S, Hassan NE, Brown TC, Alt EU, Robinson JE, Badr FM, Braun SE. Identification and Targeting of Thomsen-Friedenreich and IL1RAP Antigens on Chronic Myeloid Leukemia Stem Cells Using Bi-Specific Antibodies. Onco Targets Ther 2021; 14:609-621. [PMID: 33519209 PMCID: PMC7837560 DOI: 10.2147/ott.s255299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Accepted: 11/09/2020] [Indexed: 12/12/2022] Open
Abstract
Introduction Quiescent leukemia stem cells (LSCs) play a major role in therapeutic resistance and disease progression of chronic myeloid leukemia (CML). LSCs belong to the primitive population; CD34+CD38-Lin-, which does not distinguish normal hematopoietic stem cells (HSC) from CML LSCs. Because Thomsen–Friedenreich/CD176 antigen is expressed on CD34+ HSC and IL1RAP is tightly correlated to BCR-ABL expression, we sought to increase the specificity towards LSC by using additional biomarkers. Methods We evaluated the co-expression of both antigens on CD34+ peripheral blood mononuclear cells (PBMCs) from both healthy volunteers and CML patients, using flow cytometry. Then, we used site-directed mutagenesis to induce knob-in-hole mutations in the human IgG heavy chain and the human lambda light chain to generate the bi-specific antibody (Bis-Ab) TF/RAP that binds both antigens simultaneously. We measured complement-directed cytotoxicity (CDC) in CML samples with the Bis-Ab by flow cytometry. Results In contrast to healthy volunteers, CML samples displayed a highly significant co-expression of CD176 and IL1RAP. When either a double-positive cell line or CML samples were treated with increasing doses of Bis-Ab, increased binding and CDC was observed indicating co-operative binding of the Bis-Ab as compared to monoclonal antibodies. Discussion These results show that the bi-specific antibody is capable of targeting IL1RAP+ and CD176+ cell population among CML PBMCs, but not corresponding normal cells in CDC assay. We hereby offer a novel strategy for the depletion of CML stem cells from the bulk population in clinical hematopoietic stem cell transplantation.
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Affiliation(s)
- Raghda E Eldesouki
- Genetics Unit, Department of Histology and Cell Biology, School of Medicine, Suez Canal University, Ismailia, Egypt.,Division of Immunology, Tulane National Primate Research Center, Covington, LA, USA
| | - Chengxiang Wu
- Division of Immunology, Tulane National Primate Research Center, Covington, LA, USA
| | - Fayez M Saleh
- Division of Immunology, Tulane National Primate Research Center, Covington, LA, USA.,Department of Medical Microbiology, Faculty of Medicine, University of Tabuk, Tabuk, Kingdom of Saudi Arabia
| | - Eman Abdel-Moemen Mohammed
- Genetics Unit, Department of Histology and Cell Biology, School of Medicine, Suez Canal University, Ismailia, Egypt
| | - Soha Younes
- Department of Clinical pathology, Faculty of Medicine, Suez Canal University, Ismailia, Egypt
| | | | - Theresa C Brown
- Hayward Genetics Center, Tulane University School of Medicine, New Orleans, LA, USA
| | - Eckhard U Alt
- Applied Stem Cell Laboratory, Departments of Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - James E Robinson
- Sections of Infectious Disease, Departments of Pediatrics and Internal Medicine, Tulane University School of Medicine, New Orleans, LA, USA
| | - Fouad Mohamed Badr
- Genetics Unit, Department of Histology and Cell Biology, School of Medicine, Suez Canal University, Ismailia, Egypt
| | - Stephen E Braun
- Division of Immunology, Tulane National Primate Research Center, Covington, LA, USA.,Departments of Pharmacology, Tulane University School of Medicine, New Orleans, LA, USA
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The Role of Complement in the Mechanism of Action of Therapeutic Anti-Cancer mAbs. Antibodies (Basel) 2020; 9:antib9040058. [PMID: 33126570 PMCID: PMC7709112 DOI: 10.3390/antib9040058] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 09/04/2020] [Accepted: 09/21/2020] [Indexed: 02/07/2023] Open
Abstract
Unconjugated anti-cancer IgG1 monoclonal antibodies (mAbs) activate antibody-dependent cellular cytotoxicity (ADCC) by natural killer (NK) cells and antibody-dependent cellular phagocytosis (ADCP) by macrophages, and these activities are thought to be important mechanisms of action for many of these mAbs in vivo. Several mAbs also activate the classical complement pathway and promote complement-dependent cytotoxicity (CDC), although with very different levels of efficacy, depending on the mAb, the target antigen, and the tumor type. Recent studies have unraveled the various structural factors that define why some IgG1 mAbs are strong mediators of CDC, whereas others are not. The role of complement activation and membrane inhibitors expressed by tumor cells, most notably CD55 and CD59, has also been quite extensively studied, but how much these affect the resistance of tumors in vivo to IgG1 therapeutic mAbs still remains incompletely understood. Recent studies have demonstrated that complement activation has multiple effects beyond target cell lysis, affecting both innate and adaptive immunity mediated by soluble complement fragments, such as C3a and C5a, and by stimulating complement receptors expressed by immune cells, including NK cells, neutrophils, macrophages, T cells, and dendritic cells. Complement activation can enhance ADCC and ADCP and may contribute to the vaccine effect of mAbs. These different aspects of complement are also briefly reviewed in the specific context of FDA-approved therapeutic anti-cancer IgG1 mAbs.
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Taylor RP, Lindorfer MA. How Do mAbs Make Use of Complement to Kill Cancer Cells? The Role of Ca 2. Antibodies (Basel) 2020; 9:E45. [PMID: 32899722 PMCID: PMC7551823 DOI: 10.3390/antib9030045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 08/19/2020] [Accepted: 08/26/2020] [Indexed: 12/11/2022] Open
Abstract
We examined the kinetics and mechanisms by which monoclonal antibodies (mAbs) utilize complement to rapidly kill targeted cancer cells. Based on results from flow cytometry, confocal microscopy and high-resolution digital imaging experiments, the general patterns which have emerged reveal cytotoxic activities mediated by substantial and lethal Ca2+ fluxes. The Ca2+ fluxes are common to the reported pathways that have been utilized by other toxins in killing nucleated cells. These reactions terminate in very high levels of cell killing, and based on these considerations, we suggest additional strategies to further enhance mAb-based targeting of cancer with complement.
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Affiliation(s)
- Ronald P. Taylor
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA;
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Goldberg BS, Ackerman ME. Antibody-mediated complement activation in pathology and protection. Immunol Cell Biol 2020; 98:305-317. [PMID: 32142167 DOI: 10.1111/imcb.12324] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 02/27/2020] [Accepted: 03/03/2020] [Indexed: 01/10/2023]
Abstract
Antibody-dependent complement activity is associated not only with autoimmune morbidity, but also with antitumor efficacy. In infectious disease, both recombinant monoclonal antibodies and polyclonal antibodies generated in natural adaptive responses can mediate complement activity to protective, therapeutic or disease-enhancing effect. Recent advances have contributed to the structural resolution of molecular complexes involved in antibody-mediated complement activation, defining the avid nature of participating interactions and pointing to how antibody isotype, subclass, hinge flexibility, glycosylation state, amino acid sequence and the contextual nature of the cognate antigen/epitope are all factors that can determine complement activity through impact on antibody multimerization and subsequent recruitment of complement component 1q. Beyond the efficiency of activation, complement activation products interact with various cell types that mediate immune adherence, trafficking, immune education and innate functions. Similarly, depending on the anatomical location and extent of activation, complement can support homeostatic restoration or be leveraged by pathogens or neoplasms to enhance infection or promote tumorigenic microenvironments, respectively. Advances in means to suppress complement activation by intravenous immunoglobulin (IVIG), IVIG mimetics and complement-intervening antibodies represent proven and promising exploratory therapeutic strategies, while antibody engineering has likewise offered frameworks to enhance, eliminate or isolate complement activation to interrogate in vivo mechanisms of action. Such strategies promise to support the optimization of antibody-based drugs that are able to tackle emerging and difficult-to-treat diseases by improving our understanding of the synergistic and antagonistic relationships between antibody mechanisms mediated by Fc receptors, direct binding and the products of complement activation.
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Affiliation(s)
| | - Margaret E Ackerman
- Thayer School of Engineering, Dartmouth College, Hanover, NH, USA.,Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
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Complement fragments are biomarkers of antibody-mediated endothelial injury. Mol Immunol 2019; 118:142-152. [PMID: 31884386 DOI: 10.1016/j.molimm.2019.12.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 11/18/2019] [Accepted: 12/16/2019] [Indexed: 11/23/2022]
Abstract
Antibody-mediated rejection (AbMR) adversely affects long-term graft survival in kidney transplantation. Currently, the diagnosis of AbMR requires a kidney biopsy, and detection of complement C4d deposition in the allograft is one of the diagnostic criteria. Complement activation also generates several soluble fragments which could potentially provide non-invasive biomarkers of the process. Furthermore, microvesicles released into the plasma from injured cells can serve as biomarkers of vascular injury. To explore whether soluble complement fragments or complement fragments bound to endothelial microvesicles can be used to non-invasively detect AbMR, we developed an in vitro model in which human endothelial cells were exposed to anti-HLA antibodies and complement sufficient serum. We found that complement fragments C4a and sC5b-9 were increased in the supernatants of cells exposed to complement-sufficient serum compared to cells treated complement-deficient serum. Furthermore, complement activation on the cell surface was associated with the release of microvesicles bearing C4 and C3 fragments. We next measured these analytes in plasma from kidney transplant recipients with biopsy-proven acute AbMR (n = 9) and compared the results with those from transplant recipients who also had impaired allograft function but who did not have AbMR (n = 30). Consistent with the in vitro results, complement fragments C4a and Ba were increased in plasma from patients with AbMR compared to control subjects (P < 0.001 and P < 0.01, respectively). Endothelial microvesicle counts were not increased in patients with AbMR, however, and the number of microvesicles with C4 and C3 bound to the surface was actually lower compared to control subjects (both P < 0.05). Our results suggest that plasma complement activation fragments may be useful as non-invasive biomarkers of antibody-mediated complement activation within the allograft. Complement-opsonized endothelial microvesicles are decreased in patients with AbMR, possibly due to enhanced clearance of microvesicles opsonized with C3 and C4 fragments.
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Seledtsov VI, Seledtsova GV. Total threshold cytotoxicity of therapeutic antibodies for selective destruction of pathogenic memory T cells: implications for immunotherapy of autoimmune and allergenic disorders. Expert Rev Clin Immunol 2019; 15:701-706. [DOI: 10.1080/1744666x.2019.1617698] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Victor I. Seledtsov
- Center for Medical Biotechnologies, lmmanuel Kant Baltic Federal University, Kaliningrad, Russia
| | - Galina V. Seledtsova
- Laboratory for Cellular Technologies, Institute for Fundamental and Clinical Immunology, Novosibirsk, Russia
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Seledtsov VI, Seledtsova GV. Attaining threshold antibody cytotoxicity for selective tumor cell destruction: an opinion article. Oncotarget 2018; 9:35790-35794. [PMID: 30515270 PMCID: PMC6254663 DOI: 10.18632/oncotarget.26271] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/06/2018] [Indexed: 11/25/2022] Open
Abstract
We propose a novel immunotherapeutic paradigm that justifies application of several antibodies to various membrane-associated antigens to achieve a critical threshold density of immune complexes on the surface of cancer cells sufficient for triggering downstream cytolytic pathways. Indeed, some cancer-associated antigens (such as cancer/testis antigens) were found to be expressed on many cancer (but not normal) cells, with their baseline membrane expression levels being originally quite low for some of them, or even further down-regulated due to immune-driven cell selection. To achieve the mandatory threshold density of membrane-associated immune complexes on malignant cells, the concept stipulates combined application of antibodies specific for a cancer-associated antigen along with antibodies against an antigen expressed not only on tumor, but also on normal cells. In the proposed scenario it is of vital importance that the latter antibodies should be applied in suboptimal dosage to exclude the destruction of normal cells devoid of a cancer-associated antigen. Malignant cells often co-express antigens not present concurrently on normal cells at high levels. In such cases, suboptimal dosages of antibodies specific for those antigens could also be applied to achieve cumulative effect leading to selective destruction of tumour cells. Hence, the described immunotherapeutic technology could be used metaphorically speaking as a kind of ‘immunological knife’, which is capable of highly selective destruction of cancer cells without destroying normal cells.
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Taylor RP, Lindorfer MA. Cytotoxic mechanisms of immunotherapy: Harnessing complement in the action of anti-tumor monoclonal antibodies. Semin Immunol 2016; 28:309-16. [PMID: 27009480 DOI: 10.1016/j.smim.2016.03.003] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/07/2016] [Indexed: 01/02/2023]
Abstract
Several mAbs that have been approved for the treatment of cancer make use of complement-dependent cytotoxicity (CDC) to eliminate tumor cells. Comprehensive investigations, based on in vitro studies, mouse models and analyses of patient blood samples after mAb treatment have provided key insights into the details of individual steps in the CDC reaction. Based on the lessons learned from these studies, new and innovative approaches are now being developed to increase the clinical efficacy of next generation mAbs with respect to CDC. These improvements include engineering changes in the mAbs to enhance their ability to activate complement. In addition, mAb dosing paradigms are being developed that take into account the capacity as well as the limitations of the complement system to eliminate a substantial burden of mAb-opsonized cells. Over the next few years it is likely these approaches will lead to mAbs that are far more effective in the treatment of cancer.
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Affiliation(s)
- Ronald P Taylor
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, United States.
| | - Margaret A Lindorfer
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA 22908, United States
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Mamidi S, Höne S, Kirschfink M. The complement system in cancer: Ambivalence between tumour destruction and promotion. Immunobiology 2015; 222:45-54. [PMID: 26686908 DOI: 10.1016/j.imbio.2015.11.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Revised: 10/08/2015] [Accepted: 11/19/2015] [Indexed: 12/14/2022]
Abstract
Constituting a part of the innate immune system, the complement system consists of over 50 proteins either acting as part of a 3-branch activation cascade, a well-differentiated regulatory system in fluid phase or on each tissue, or as receptors translating the activation signal to multiple cellular effector functions. Complement serves as first line of defence against infections from bacteria, viruses and parasites by orchestrating the immune response through opsonisation, recruitment of immune cells to the site of infection and direct cell lysis. Complement is generally recognised as a protective mechanism against the formation of tumours in humans, but is often limited by various resistance mechanisms interfering with its cytotoxic action, now considered as a great barrier of successful antibody-based immunotherapy. However, recent studies also indicate a pro-tumourigenic potential of complement in certain cancers and under certain conditions. In this review, we present recent findings on the possible dual role of complement in destroying cancer, especially if resistance mechanisms are blocked, but also under certain inflammatory conditions-promoting tumour development.
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Affiliation(s)
| | - Simon Höne
- Institute for Immunology, University of Heidelberg, Germany
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Targeted delivery of siRNA using transferrin-coupled lipoplexes specifically sensitizes CD71 high expressing malignant cells to antibody-mediated complement attack. Target Oncol 2014; 10:405-13. [DOI: 10.1007/s11523-014-0345-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 10/29/2014] [Indexed: 01/08/2023]
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Meyer S, Leusen JHW, Boross P. Regulation of complement and modulation of its activity in monoclonal antibody therapy of cancer. MAbs 2014; 6:1133-44. [PMID: 25517299 PMCID: PMC4622586 DOI: 10.4161/mabs.29670] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The complement system is a powerful tool of the innate immune system to eradicate pathogens. Both in vitro and in vivo evidence indicates that therapeutic anti-tumor monoclonal antibodies (mAbs) can activate the complement system by the classical pathway. However, the contribution of complement to the efficacy of mAbs is still debated, mainly due to the lack of convincing data in patients. A beneficial role for complement during mAb therapy is supported by the fact that cancer cells often upregulate complement-regulatory proteins (CRPs). Polymorphisms in various CRPs were previously associated with complement-mediated disorders. In this review the role of complement in anti-tumor mAb therapy will be discussed with special emphasis on strategies aiming at modifying complement activity. In the future, clinical efficacy of mAbs with enhanced effector functions together with comprehensive analysis of polymorphisms in CRPs in mAb-treated patients will further clarify the role of complement in mAb therapy.
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Affiliation(s)
- Saskia Meyer
- a Laboratory for Immunotherapy; Laboratory for Translational Immunology (LTI) ; University Medical Center Utrecht ; Utrecht , The Netherlands
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