Directed evolution of and structural insights into antibody-mediated disruption of a stable receptor-ligand complex

AbstractAntibody drugs exert therapeutic effects via a range of mechanisms, including competitive inhibition, allosteric modulation, and immune effector mechanisms. Facilitated dissociation is an additional mechanism where antibody-mediated “disruption” of stable high-affinity macromolecular complexes can potentially enhance therapeutic efficacy. However, this mechanism is not well understood or utilized therapeutically. Here, we investigate and engineer the weak disruptive activity of an existing therapeutic antibody, omalizumab, which targets IgE antibodies to block the allergic response. We develop a yeast display approach to select for and engineer antibody disruptive efficiency and generate potent omalizumab variants that dissociate receptor-bound IgE. We determine a low resolution cryo-EM structure of a transient disruption intermediate containing the IgE-Fc, its partially dissociated receptor and an antibody inhibitor. Our results provide a conceptual framework for engineering disruptive inhibitors for other targets, insights into the failure in clinical trials of the previous high affinity omalizumab HAE variant and anti-IgE antibodies that safely and rapidly disarm allergic effector cells.

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Antiinflammatory and Immunomodulating Properties of Fungal Metabolites

Mediators of Inflammation ◽

10.1155/mi.2005.63 ◽

2005 ◽

Vol 2005 (2) ◽

pp. 63-80 ◽

Cited By ~ 179

Author(s):

Cristina Lull ◽

Harry J. Wichers ◽

Huub F. J. Savelkoul

Keyword(s):

Molecular Mechanisms ◽

Therapeutic Effects ◽

Fungal Metabolites ◽

Necrosis Factor Alpha ◽

Immune Effector ◽

Effector Cells ◽

Immune Effector Cells ◽

Factor Alpha ◽

Active Substances ◽

Necrosis Factor

We discuss current information on the ability of extracts and isolated metabolites from mushrooms to modulate immune responses. This can result in a more enhanced innate and acquired disease resistance. The major immunomodulating effects of these active substances derived from mushrooms include mitogenicity and activation of immune effector cells, such as lymphocytes, macrophages, and natural killer cells, resulting in the production of cytokines, including interleukins (ILs), tumor necrosis factor alpha (TNF)-α, and interferon gamma (INF)-γ. In particular, the ability of selective mushroom extracts to modulate the differentiation capacity of CD4+T cells to mature into TH1and/or TH2subsets will be discussed. As a consequence these extracts will have profound effects in particular diseases, like chronic autoimmune TH1-mediated or allergic TH2-mediated diseases. Immunosuppressive effects by mushroom components have also been observed. The therapeutic effects of mushrooms, such as anticancer activity, suppression of autoimmune diseases, and allergy have been associated with their immunomodulating effects. However, further studies are needed to determine the molecular mechanisms of the immunomodulating effects of mushrooms metabolites both individually and in complex mixtures, for example, extracts.

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Targeting HIF-1 alpha transcriptional activity drives cytotoxic immune effector cells into melanoma and improves combination immunotherapy

Oncogene ◽

10.1038/s41388-021-01846-x ◽

2021 ◽

Author(s):

Audrey Lequeux ◽

Muhammad Zaeem Noman ◽

Malina Xiao ◽

Kris Van Moer ◽

Meriem Hasmim ◽

...

Keyword(s):

Tumor Microenvironment ◽

Cancer Immunotherapy ◽

Transcriptional Activity ◽

Immune Cell ◽

Tumor Resistance ◽

Combination Strategy ◽

Immune Effector ◽

Effector Cells ◽

Melanoma Patients ◽

The Impact

AbstractHypoxia is a key factor responsible for the failure of therapeutic response in most solid tumors and promotes the acquisition of tumor resistance to various antitumor immune effectors. Reshaping the hypoxic immune suppressive tumor microenvironment to improve cancer immunotherapy is still a relevant challenge. We investigated the impact of inhibiting HIF-1α transcriptional activity on cytotoxic immune cell infiltration into B16-F10 melanoma. We showed that tumors expressing a deleted form of HIF-1α displayed increased levels of NK and CD8+ effector T cells in the tumor microenvironment, which was associated with high levels of CCL2 and CCL5 chemokines. We showed that combining acriflavine, reported as a pharmacological agent preventing HIF-1α/HIF-1β dimerization, dramatically improved the benefit of cancer immunotherapy based on TRP-2 peptide vaccination and anti-PD-1 blocking antibody. In melanoma patients, we revealed that tumors exhibiting high CCL5 are less hypoxic, and displayed high NK, CD3+, CD4+ and CD8+ T cell markers than those having low CCL5. In addition, melanoma patients with high CCL5 in their tumors survive better than those having low CCL5. This study provides the pre-clinical proof of concept for a novel triple combination strategy including blocking HIF-1α transcription activity along vaccination and PD-1 blocking immunotherapy.

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The Role of Microglia in Sporadic Alzheimer’s Disease

Journal of Alzheimer s Disease ◽

10.3233/jad-201248 ◽

2021 ◽

Vol 79 (3) ◽

pp. 961-968

Author(s):

Wolfgang J. Streit ◽

Habibeh Khoshbouei ◽

Ingo Bechmann

Keyword(s):

Alzheimer’S Disease ◽

Alzheimer's Disease ◽

Late Onset ◽

Genetic Mutations ◽

Sporadic Alzheimer’S Disease ◽

Immune Effector ◽

Effector Cells ◽

Immune Effector Cells ◽

Amyloid Cascade

Microglia constitute the brain’s immune system and their involvement in Alzheimer’s disease has been discussed. Commonly, and in line with the amyloid/neuroinflammation cascade hypothesis, microglia have been portrayed as potentially dangerous immune effector cells thought to be overactivated by amyloid and producing neurotoxic inflammatory mediators that lead to neurofibrillary degeneration. We disagree with this theory and offer as an alternative the microglial dysfunction theory stating that microglia become impaired in their normally neuroprotective roles because of aging, i.e., they become senescent and aging neurons degenerate because they lack the needed microglial support for their survival. Thus, while the amyloid cascade theory relies primarily on genetic data, the dysfunction theory incorporates aging as a critical etiological factor. Aging is the greatest risk factor for the sporadic (late-onset) and most common form of Alzheimer’s disease, where fully penetrant genetic mutations are absent. In this review, we lay out and discuss the human evidence that supports senescent microglial dysfunction and conflicts with the amyloid/neuroinflammation idea.

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Next-generation cell therapies: the emerging role of CAR-NK cells

Hematology ◽

10.1182/hematology.2020002547 ◽

2020 ◽

Vol 2020 (1) ◽

pp. 570-578

Author(s):

Rafet Basar ◽

May Daher ◽

Katayoun Rezvani

Keyword(s):

T Cells ◽

Cell Therapy ◽

Natural Killer ◽

Γδ T Cells ◽

Antigen Receptors ◽

T Cell Therapy ◽

Cell Therapies ◽

Immune Effector ◽

Effector Cells ◽

Immune Effector Cells

Abstract T cells engineered with chimeric antigen receptors (CARs) have revolutionized the field of cell therapy and changed the paradigm of treatment for many patients with relapsed or refractory B-cell malignancies. Despite this progress, there are limitations to CAR-T cell therapy in both the autologous and allogeneic settings, including practical, logistical, and toxicity issues. Given these concerns, there is a rapidly growing interest in natural killer cells as alternative vehicles for CAR engineering, given their unique biological features and their established safety profile in the allogeneic setting. Other immune effector cells, such as invariant natural killer T cells, γδ T cells, and macrophages, are attracting interest as well and eventually may be added to the repertoire of engineered cell therapies against cancer. The pace of these developments will undoubtedly benefit from multiple innovative technologies, such as the CRISPR-Cas gene editing system, which offers great potential to enhance the natural ability of immune effector cells to eliminate refractory cancers.

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Soluble CD70: a novel immunotherapeutic agent for experimental glioblastoma

Journal of Neurosurgery ◽

10.3171/2009.11.jns09901 ◽

2010 ◽

Vol 113 (2) ◽

pp. 280-285 ◽

Cited By ~ 18

Author(s):

James Miller ◽

Guenter Eisele ◽

Ghazaleh Tabatabai ◽

Steffen Aulwurm ◽

Gabriele von Kürthy ◽

...

Keyword(s):

T Cells ◽

Immune Responses ◽

Malignant Gliomas ◽

Ectopic Expression ◽

Glioma Cells ◽

Interferon Γ ◽

Soluble Form ◽

Immune Effector ◽

Effector Cells ◽

Immune Effector Cells

Object Given the overall poor outcome with current treatment strategies in malignant gliomas, immunotherapy has been considered a promising experimental approach to glioblastoma for more than 2 decades. A cell surface molecule, CD70, may induce potent antitumor immune responses via activation of the costimulatory receptor CD27 expressed on immune effector cells. There is evidence that a soluble form of CD70 (sCD70) may exhibit biological activity, too. A soluble costimulatory ligand is attractive because it may facilitate immune activation and may achieve a superior tissue distribution. Methods To test the antiglioma effect of sCD70, the authors genetically modified SMA-560 mouse glioma cells to secrete the extracellular domain of CD70. They assessed the immunogenicity of the transfected cells in cocultures with immune effector cells by the determination of immune cell proliferation and the release of interferon-γ. Syngeneic VM/Dk mice were implanted orthotopically with control or sCD70-releasing glioma cells to determine a survival benefit mediated by sCD70. Depletion studies were performed to identify the cellular mediators of prolonged survival of sCD70-releasing glioma-bearing mice. Results The authors found that ectopic expression of sCD70 enhanced the proliferation and interferon-γ release of syngeneic splenocytes in vitro. More importantly, sCD70 prolonged the survival of syngeneic VM/Dk mice bearing intracranial SMA-560 gliomas. The survival rate at 60 days increased from 5 to 45%. Antibody-mediated depletion of CD8-positive T cells abrogates the survival advantage conferred by sCD70. Conclusions These data suggest that sCD70 is a potent stimulator of antiglioma immune responses that depend critically on CD8-positive T cells. Soluble CD70 could be a powerful adjuvant for future immunotherapy trials for glioblastoma.

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Sequential class switching is required for the generation of high affinity IgE antibodies

Journal of Experimental Medicine ◽

10.1084/jem.20111941 ◽

2012 ◽

Vol 209 (2) ◽

pp. 353-364 ◽

Cited By ~ 147

Author(s):

Huizhong Xiong ◽

Jayashree Dolpady ◽

Matthias Wabl ◽

Maria A. Curotto de Lafaille ◽

Juan J. Lafaille

Keyword(s):

Affinity Maturation ◽

Class Switching ◽

Ige Antibodies ◽

High Affinity ◽

Low Concentrations ◽

Ige Response

IgE antibodies with high affinity for their antigens can be stably cross-linked at low concentrations by trace amounts of antigen, whereas IgE antibodies with low affinity bind their antigens weakly. In this study, we find that there are two distinct pathways to generate high and low affinity IgE. High affinity IgE is generated through sequential class switching (μ→γ→ε) in which an intermediary IgG phase is necessary for the affinity maturation of the IgE response, where the IgE inherits somatic hypermutations and high affinity from the IgG1 phase. In contrast, low affinity IgE is generated through direct class switching (μ→ε) and is much less mutated. Mice deficient in IgG1 production cannot produce high affinity IgE, even after repeated immunizations. We demonstrate that a small amount of high affinity IgE can cause anaphylaxis and is pathogenic. Low affinity IgE competes with high affinity IgE for binding to Fcε receptors and prevents anaphylaxis and is thus beneficial.

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Bone marrow transplantation and approaches to avoid graft-versus-host disease (GVHD)

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2005.1701 ◽

2005 ◽

Vol 360 (1461) ◽

pp. 1747-1767 ◽

Cited By ~ 42

Author(s):

Bruce R Blazar ◽

William J Murphy

Keyword(s):

Graft Versus Host Disease ◽

Opportunistic Infections ◽

Haematopoietic Stem Cell ◽

Generation Process ◽

Host Disease ◽

Immune Effector ◽

Effector Cells ◽

Graft Versus Host ◽

Donor T Cells ◽

Donor Graft

Haematopoietic stem cell transplantation (HSCT) offers promise for the treatment of haematological and immune disorders, solid tumours, and as a tolerance inducing regimen for organ transplantation. Allogeneic HSCTs engraftment requires immunosuppression and the anti-tumour effects are dependent upon the immune effector cells that are contained within or generated from the donor graft. However, significant toxicities currently limit its efficacy. These problems include: (i) graft-versus-host disease (GVHD) in which donor T cells attack the recipient resulting in multi-organ attack and morbidity, (ii) a profound period of immune deficiency following HSCT, and (iii) donor graft rejection. Currently available methods to prevent or treat GVHD with systemic immunosuppression can lead to impaired immune recovery, increased opportunistic infections, and higher relapse rates. This review will provide an overview of GVHD pathophysiology and discuss the roles of various cells, pathways, and factors in the GVHD generation process and in the preservation of graft-versus-tumour effects. Variables that need to be taken into consideration in attempting to extrapolate preclinical results to the clinical paradigm will be highlighted.

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Depletion of immune effector cells induces myocardial damage in the acute experimental Trypanosoma cruzi infection: ultrastructural study in rats

Tissue and Cell ◽

10.1054/tice.1999.0040 ◽

1999 ◽

Vol 31 (3) ◽

pp. 281-290 ◽

Cited By ~ 13

Author(s):

R.C.N. Melo

Keyword(s):

Trypanosoma Cruzi ◽

Ultrastructural Study ◽

Myocardial Damage ◽

Immune Effector ◽

Effector Cells ◽

Immune Effector Cells ◽

Cruzi Infection

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Antibody-based therapy of leukaemia

Expert Reviews in Molecular Medicine ◽

10.1017/s1462399409001215 ◽

2009 ◽

Vol 11 ◽

Cited By ~ 25

Author(s):

John C. Morris ◽

Thomas A. Waldmann

Keyword(s):

Monoclonal Antibodies ◽

T Cell ◽

B Cell ◽

Gemtuzumab Ozogamicin ◽

Cell Leukaemia ◽

Target Cells ◽

Immune Effector ◽

Effector Cells ◽

Prolymphocytic Leukaemia ◽

Immune Effector Cells

Over the past decade, monoclonal antibodies have dramatically impacted the treatment of haematological malignancies, as evidenced by the effect of rituximab on the response rate and survival of patients with follicular and diffuse large B cell non-Hodgkin's lymphoma. Currently, only two monoclonal antibodies – the anti-CD33 immunotoxin gemtuzumab ozogamicin and the CD52-directed antibody alemtuzumab – are approved for treatment of relapsed acute myeloid leukaemia in older patients and B cell chronic lymphocytic leukaemia, respectively. Although not approved for such treatment, alemtuzumab is also active against T cell prolymphocytic leukaemia, cutaneous T cell lymphoma and Sézary syndrome, and adult T cell leukaemia and lymphoma. In addition, rituximab has demonstrated activity against B cell chronic lymphocytic and hairy cell leukaemia. Monoclonal antibodies targeting CD4, CD19, CD20, CD22, CD23, CD25, CD45, CD66 and CD122 are now being studied in the clinic for the treatment of leukaemia. Here, we discuss how these new antibodies have been engineered to reduce immunogenicity and improve antibody targeting and binding. Improved interactions with Fc receptors on immune effector cells can enhance destruction of target cells through antibody-dependent cellular cytotoxicity and complement-mediated cell lysis. The antibodies can also be armed with cellular toxins or radionuclides to enhance the destruction of leukaemia cells.

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