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Li Y, Shen H, Zhang R, Ji C, Wang Y, Su C, Xiao J. Immunoglobulin M perception by FcμR. Nature 2023; 615:907-912. [PMID: 36949194 DOI: 10.1038/s41586-023-05835-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 02/13/2023] [Indexed: 03/24/2023]
Abstract
Immunoglobulin M (IgM) is the first antibody to emerge during embryonic development and the humoral immune response1. IgM can exist in several distinct forms, including monomeric, membrane-bound IgM within the B cell receptor (BCR) complex, pentameric and hexameric IgM in serum and secretory IgM on the mucosal surface. FcμR, the only IgM-specific receptor in mammals, recognizes different forms of IgM to regulate diverse immune responses2-5. However, the underlying molecular mechanisms remain unknown. Here we delineate the structural basis of the FcμR-IgM interaction by crystallography and cryo-electron microscopy. We show that two FcμR molecules interact with a Fcμ-Cμ4 dimer, suggesting that FcμR can bind to membrane-bound IgM with a 2:1 stoichiometry. Further analyses reveal that FcμR-binding sites are accessible in the context of IgM BCR. By contrast, pentameric IgM can recruit four FcμR molecules to bind on the same side and thereby facilitate the formation of an FcμR oligomer. One of these FcμR molecules occupies the binding site of the secretory component. Nevertheless, four FcμR molecules bind to the other side of secretory component-containing secretory IgM, consistent with the function of FcμR in the retrotransport of secretory IgM. These results reveal intricate mechanisms of IgM perception by FcμR.
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Affiliation(s)
- Yaxin Li
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Hao Shen
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Ruixue Zhang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, P. R. China
| | - Chenggong Ji
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Yuxin Wang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Chen Su
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China
| | - Junyu Xiao
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, P. R. China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, P. R. China.
- Changping Laboratory, Beijing, P. R. China.
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2
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Kubagawa H, Honjo K, Ohkura N, Sakaguchi S, Radbruch A, Melchers F, Jani PK. Functional Roles of the IgM Fc Receptor in the Immune System. Front Immunol 2019; 10:945. [PMID: 31130948 PMCID: PMC6509151 DOI: 10.3389/fimmu.2019.00945] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Accepted: 04/12/2019] [Indexed: 12/14/2022] Open
Abstract
It is now evident from studies of mice unable to secrete IgM that both non-immune “natural” and antigen-induced “immune” IgM are important for protection against pathogens and for regulation of immune responses to self-antigens. Since identification of its Fc receptor (FcμR) by a functional cloning strategy in 2009, the roles of FcμR in these IgM effector functions have begun to be explored. Unlike Fc receptors for switched Ig isotypes (e.g., FcγRs, FcεRs, FcαR, Fcα/μR, pIgR, FcRn), FcμR is selectively expressed by lymphocytes: B, T, and NK cells in humans and only B cells in mice. FcμR may have dual signaling ability: one through a potential as yet unidentified adaptor protein non-covalently associating with the FcμR ligand-binding chain via a His in transmembrane segment and the other through its own Tyr and Ser residues in the cytoplasmic tail. FcμR binds pentameric and hexameric IgM with a high avidity of ~10 nM in solution, but more efficiently binds IgM when it is attached to a membrane component via its Fab region on the same cell surface (cis engagement). Four different laboratories have generated Fcmr-ablated mice and eight different groups of investigators have examined the resultant phenotypes. There have been some clear discrepancies reported that appear to be due to factors including differences in the exons of Fcmr that were targeted to generate the knockouts. One common feature among these different mutant mice, however, is their propensity to produce autoantibodies of both IgM and IgG isotypes. In this review, we briefly describe recent findings concerning the functions of FcμR in both mice and humans and propose a model for how FcμR plays a regulatory role in B cell tolerance.
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Affiliation(s)
| | - Kazuhito Honjo
- Department of Medicine, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Naganari Ohkura
- Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Shimon Sakaguchi
- Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | | | | | - Peter K Jani
- Deutsches Rheuma-Forschungszentrum, Berlin, Germany
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3
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A CD19/CD3 bispecific antibody for effective immunotherapy of chronic lymphocytic leukemia in the ibrutinib era. Blood 2018; 132:521-532. [PMID: 29743179 DOI: 10.1182/blood-2018-02-830992] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Accepted: 04/29/2018] [Indexed: 12/13/2022] Open
Abstract
The Bruton tyrosine kinase inhibitor ibrutinib induces high rates of clinical response in chronic lymphocytic leukemia (CLL). However, there remains a need for adjunct treatments to deepen response and to overcome drug resistance. Blinatumomab, a CD19/CD3 bispecific antibody (bsAb) designed in the BiTE (bispecific T-cell engager) format, is approved by the US Food and Drug Administration for the treatment of relapsed or refractory B-cell precursor acute lymphoblastic leukemia. Because of its short half-life of 2.1 hours, blinatumomab requires continuous intravenous dosing for efficacy. We developed a novel CD19/CD3 bsAb in the single-chain Fv-Fc format (CD19/CD3-scFv-Fc) with a half-life of ∼5 days. In in vitro experiments, both CD19/CD3-scFv-Fc and blinatumomab induced >90% killing of CLL cells from treatment-naïve patients. Antileukemic activity was associated with increased autologous CD8 and CD4 T-cell proliferation, activation, and granzyme B expression. In the NOD/SCID/IL2Rγnull patient-derived xenograft mouse model, once-weekly treatment with CD19/CD3-scFv-Fc eliminated >98% of treatment-naïve CLL cells in blood and spleen. By contrast, blinatumomab failed to induce a response, even when administered daily. We next explored the activity of CD19/CD3-scFv-Fc in the context of ibrutinib treatment and ibrutinib resistance. CD19/CD3-scFv-Fc induced more rapid killing of CLL cells from ibrutinib-treated patients than those from treatment-naïve patients. CD19/CD3-scFv-Fc also demonstrated potent activity against CLL cells from patients with acquired ibrutinib-resistance harboring BTK and/or PLCG2 mutations in vitro and in vivo using patient-derived xenograft models. Taken together, these data support investigation of CD19/CD3 bsAb's and other T cell-recruiting bsAb's as immunotherapies for CLL, especially in combination with ibrutinib or as rescue therapy in ibrutinib-resistant disease.
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Abstract
Site-specific conjugation methods are becoming increasingly important in building next-generation antibody-drug conjugates. We have developed a site-specific conjugation technology based on monoclonal antibodies with engineered selenocysteine (Sec) residues, named selenomabs. Here, we provide protocols for the engineering, expression, and purification of selenomabs in single-chain variable fragment (scFv)-Fc format. Methods for selective conjugation of selenomabs to selenol-reactive compounds and analytical characterization of selenomab conjugates are also included.
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Li X, Nelson CG, Nair RR, Hazlehurst L, Moroni T, Martinez-Acedo P, Nanna AR, Hymel D, Burke TR, Rader C. Stable and Potent Selenomab-Drug Conjugates. Cell Chem Biol 2017; 24:433-442.e6. [PMID: 28330604 DOI: 10.1016/j.chembiol.2017.02.012] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Revised: 12/16/2016] [Accepted: 02/10/2017] [Indexed: 02/06/2023]
Abstract
Selenomabs are engineered monoclonal antibodies with one or more translationally incorporated selenocysteine residues. The unique reactivity of the selenol group of selenocysteine permits site-specific conjugation of drugs. Compared with other natural and unnatural amino acid and carbohydrate residues that have been used for the generation of site-specific antibody-drug conjugates, selenocysteine is particularly reactive, permitting fast, single-step, and efficient reactions under near physiological conditions. Using a tailored conjugation chemistry, we generated highly stable selenomab-drug conjugates and demonstrated their potency and selectivity in vitro and in vivo. These site-specific antibody-drug conjugates built on a selenocysteine interface revealed broad therapeutic utility in liquid and solid malignancy models.
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Affiliation(s)
- Xiuling Li
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Christopher G Nelson
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Rajesh R Nair
- Molecular Oncology Program, H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Lori Hazlehurst
- Molecular Oncology Program, H. Lee Moffitt Cancer Center, Tampa, FL 33612, USA
| | - Tina Moroni
- Proteomics and Mass Spectrometry Core, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Pablo Martinez-Acedo
- Proteomics and Mass Spectrometry Core, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Alex R Nanna
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - David Hymel
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Terrence R Burke
- Chemical Biology Laboratory, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Christoph Rader
- Department of Cancer Biology, The Scripps Research Institute, Jupiter, FL 33458, USA; Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458, USA.
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Glycan-independent binding and internalization of human IgM to FCMR, its cognate cellular receptor. Sci Rep 2017; 7:42989. [PMID: 28230186 PMCID: PMC5322398 DOI: 10.1038/srep42989] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 01/17/2017] [Indexed: 12/17/2022] Open
Abstract
IgM is the first antibody to be produced in immune responses and plays an important role in the neutralization of bacteria and viruses. Human IgM is heavily glycosylated, featuring five N-linked glycan sites on the μ chain and one on the J-chain. Glycosylation of IgG is known to modulate the effector functions of Fcγ receptors. In contrast, little is known about the effect of glycosylation on IgM binding to the human Fcμ receptor (hFCMR). In this study, we identify the Cμ4 domain of IgM as the target of hFCMR, and show that binding and internalization of IgM by hFCMR is glycan-independent. We generated a homology-based structure for hFCMR and used molecular dynamic simulations to show how this interaction with IgM may occur. Finally, we reveal an inhibitory function for IgM in the proliferation of T cells.
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Kubagawa H, Skopnik CM, Zimmermann J, Durek P, Chang HD, Yoo E, Bertoli LF, Honjo K, Radbruch A. Authentic IgM Fc Receptor (FcμR). Curr Top Microbiol Immunol 2017; 408:25-45. [PMID: 28702710 DOI: 10.1007/82_2017_23] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Since the bona fide Fc receptor for IgM antibody (FcµR) was identified eight years ago, much progress has been made in defining its biochemical nature, cellular distribution, and effector function. However, there are clearly conflicting results, especially about the cellular distribution and function of murine FcµR. In this short article, we will discuss recent findings from us and other investigators along with our interpretations and comments that may help to resolve the existing puzzles and should open new avenues of investigation.
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Affiliation(s)
- Hiromi Kubagawa
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany.
| | | | - Jakob Zimmermann
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Pawel Durek
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Hyun-Dong Chang
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
| | - Esther Yoo
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA, 90095, USA
| | | | - Kazuhito Honjo
- Department of Medicine, University of Alabama at Birmingham, Birmingham, AL, 35209, USA
| | - Andreas Radbruch
- Deutsches Rheuma-Forschungszentrum in Berlin, 10117, Berlin, Germany
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Chimeric antigen receptor T cells targeting Fc μ receptor selectively eliminate CLL cells while sparing healthy B cells. Blood 2016; 128:1711-22. [PMID: 27535994 DOI: 10.1182/blood-2016-01-692046] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2016] [Accepted: 08/05/2016] [Indexed: 12/28/2022] Open
Abstract
Adoptive cell therapy of chronic lymphocytic leukemia (CLL) with chimeric antigen receptor (CAR)-modified T cells targeting CD19 induced lasting remission of this refractory disease in a number of patients. However, the treatment is associated with prolonged "on-target off-tumor" toxicities due to the targeted elimination of healthy B cells demanding more selectivity in targeting CLL cells. We identified the immunoglobulin M Fc receptor (FcμR), also known as the Fas apoptotic inhibitory molecule-3 or TOSO, as a target for a more selective treatment of CLL by CAR T cells. FcμR is highly and consistently expressed by CLL cells; only minor levels are detected on healthy B cells or other hematopoietic cells. T cells with a CAR specific for FcμR efficiently responded toward CLL cells, released a panel of proinflammatory cytokines and lytic factors, like soluble FasL and granzyme B, and eliminated the leukemic cells. In contrast to CD19 CAR T cells, anti-FcμR CAR T cells did not attack healthy B cells. T cells with anti-FcμR CAR delayed outgrowth of Mec-1-induced leukemia in a xenograft mouse model. T cells from CLL patients in various stages of the disease, modified by the anti-FcμR CAR, purged their autologous CLL cells in vitro without reducing the number of healthy B cells, which is the case with anti-CD19 CAR T cells. Compared with the currently used therapies, the data strongly imply a superior therapeutic index of anti-FcμR CAR T cells for the treatment of CLL.
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Pedzisa L, Li X, Rader C, Roush WR. Assessment of reagents for selenocysteine conjugation and the stability of selenocysteine adducts. Org Biomol Chem 2016; 14:5141-7. [PMID: 27184239 PMCID: PMC4887430 DOI: 10.1039/c6ob00775a] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Conventional antibody-drug conjugates (ADCs) are heterogeneous mixtures that have poor pharmacokinetic properties and decreased efficacy relative to homogenous ADCs. Furthermore, ADCs that are maleimide-based often have inadequate circulatory stability, which can result in premature drug release with consequent off-target toxicities. Selenocysteine-modified antibodies have been developed that allow site-specific antibody conjugation, yielding homogeneous ADCs. Herein, we survey several electrophilic functional groups that react with selenocystine with high efficiency. Several of these result in conjugates with stabilities that are superior to maleimide conjugates. Among these, the allenamide functional group reacts with notably high efficiency, leads to conjugates with remarkable stability, and shows exquisite selectivity for selenocysteine conjugation.
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Affiliation(s)
- Lee Pedzisa
- Department of Chemistry, The Scripps Research Institute, Scripps Florida, Jupiter FL 33458, USA.
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Sun H, Zhang L, Shi C, Hu P, Yan W, Wang Z, Duan Q, Lu F, Qin L, Lu T, Xiao J, Wang Y, Zhu F, Shao C. TOPK is highly expressed in circulating tumor cells, enabling metastasis of prostate cancer. Oncotarget 2016; 6:12392-404. [PMID: 25881543 PMCID: PMC4494946 DOI: 10.18632/oncotarget.3630] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 02/26/2015] [Indexed: 12/11/2022] Open
Abstract
Circulating tumor cells (CTCs) are important for metastasis in prostate cancer. T-LAK cell-originated protein kinase (TOPK) is highly expressed in cancer cells. Herein, we established a xenograft animal model, isolated and cultured the CTCs, and found CTCs have significantly greater migratory capacity than parental cells. TOPK is more highly expressed in the CTCs than in parental cells and is also highly expressed in the metastatic nodules caused by CTCs in mice. Knocking down TOPK decreased the migration of CTCs both in vitro and in vivo. TOPK was modulated by the PI3K/PTEN and ERK pathways during the metastasis of prostate cancer. High levels of TOPK in the tumors of patients were correlated with advanced stages of prostate cancer, especially for high-risk patients of Gleason score≥8, PSA>20ng/ml. In summary, TOPK was speculated to be one of a potential marker and therapeutic target in advanced prostate cancer.
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Affiliation(s)
- Huimin Sun
- Department of Urology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Lei Zhang
- Department of Epidemiology, Faculty of Preventive Medicine, The Fourth Military Medical University, Xian, China
| | - Changhong Shi
- Laboratory Animal Center, The Fourth Military Medical University, Xian, Shaanxi, China
| | - Peizhen Hu
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Wei Yan
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Zhe Wang
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Qiuhong Duan
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Fan Lu
- Department of Biochemistry, Department of Basic Medicine, The Fourth Military Medical University, Xian, China
| | - Lipeng Qin
- PLA Lhasa General Hospital, Lhasa, China
| | - Tao Lu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Juanjuan Xiao
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Yingmei Wang
- Department of Pathology, Xijing Hospital, The Fourth Military Medical University, Xian, China
| | - Feng Zhu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine, Huazhong University of Science and Technology, Wuhan, China
| | - Chen Shao
- Department of Urology, Xijing Hospital, The Fourth Military Medical University, Xian, China
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