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Mohan C, Zhang T, Putterman C. Pathogenic cellular and molecular mediators in lupus nephritis. Nat Rev Nephrol 2023:10.1038/s41581-023-00722-z. [PMID: 37225921 DOI: 10.1038/s41581-023-00722-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2023] [Indexed: 05/26/2023]
Abstract
Kidney involvement in patients with systemic lupus erythematosus - lupus nephritis (LN) - is one of the most important and common clinical manifestations of this disease and occurs in 40-60% of patients. Current treatment regimens achieve a complete kidney response in only a minority of affected individuals, and 10-15% of patients with LN develop kidney failure, with its attendant morbidity and considerable prognostic implications. Moreover, the medications most often used to treat LN - corticosteroids in combination with immunosuppressive or cytotoxic drugs - are associated with substantial side effects. Advances in proteomics, flow cytometry and RNA sequencing have led to important new insights into immune cells, molecules and mechanistic pathways that are instrumental in the pathogenesis of LN. These insights, together with a renewed focus on the study of human LN kidney tissue, suggest new therapeutic targets that are already being tested in lupus animal models and early-phase clinical trials and, as such, are hoped to eventually lead to meaningful improvements in the care of patients with systemic lupus erythematosus-associated kidney disease.
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Affiliation(s)
- Chandra Mohan
- Department of Biomedical Engineering, University of Houston, Houston, TX, USA.
| | - Ting Zhang
- Division of Rheumatology, the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Chaim Putterman
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel.
- Division of Rheumatology and Department of Microbiology & Immunology, Albert Einstein College of Medicine, Bronx, NY, USA.
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2
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Pisetsky DS, Shaffer R, Armstrong DD, Spencer DM. The interaction of anti-DNA antibodies with DNA antigen: Evidence for hysteresis for high avidity binding. Clin Immunol 2021; 231:108848. [PMID: 34492381 DOI: 10.1016/j.clim.2021.108848] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 07/11/2021] [Accepted: 09/02/2021] [Indexed: 10/20/2022]
Abstract
Antibodies to DNA (anti-DNA) are the serological hallmark of systemic lupus erythematosus. Previous studies have indicated that the phosphodiester backbone is the main antigenic target, with electrostatic interactions important for high avidity. To define further these interactions, the effects of ionic strength on anti-DNA binding of SLE plasmas were assessed in association and dissociation assays by ELISA. As these studies demonstrated, increasing ionic strength to a concentration of 1000 mM NaCl reduced antibody binding although the extent of the reduction varied among samples. In dissociation assays, differences among plasmas were also observed. For one of the plasmas, binding to DNA displayed resistance to dissociation by increasing ionic strength even though these concentrations limited binding in association assays. Time course studies showed a gradual change in binding interactions. These studies indicate that anti-DNA binding can involve both electrostatic and non-electrostatic interactions, with binding in some plasmas showing evidence of hysteresis.
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Affiliation(s)
- David S Pisetsky
- Medical Research Service, Durham Veterans Administration Medical Center, Durham, NC 27705, USA; Division of Rheumatology and Immunology, Duke University Medical Center, Durham, NC 27710, USA.
| | | | | | - Diane M Spencer
- Division of Rheumatology and Immunology, Duke University Medical Center, Durham, NC 27710, USA
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Hifumi E, Taguchi H, Tsuda H, Minagawa T, Nonaka T, Uda T. A new algorithm to convert a normal antibody into the corresponding catalytic antibody. SCIENCE ADVANCES 2020; 6:eaay6441. [PMID: 32232151 PMCID: PMC7096177 DOI: 10.1126/sciadv.aay6441] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 12/31/2019] [Indexed: 06/10/2023]
Abstract
Over thousands of monoclonal antibodies (mAbs) have been produced so far, and it would be valuable if these mAbs could be directly converted into catalytic antibodies. We have designed a system to realize the above concept by deleting Pro95, a highly conserved residue in CDR-3 of the antibody light chain. The deletion of Pro95 is a key contributor to catalytic function of the light chain. The S35 and S38 light chains have identical amino acid sequences except for Pro95. The former, with Pro95 did not show any catalytic activity, whereas the latter, without Pro95, exhibited peptidase activity. To verify the generality of this finding, we tested another light chain, T99wt, which had Pro95 and showed little catalytic activity. In contrast, a Pro95-deleted mutant enzymatically degraded the peptide substrate and amyloid-beta molecule. These two cases demonstrate the potential for a new method of creating catalytic antibodies from the corresponding mAbs.
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Affiliation(s)
- Emi Hifumi
- Oita University, Research Promotion Institute, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
| | - Hiroaki Taguchi
- Suzuka University of Medical Science, Faculty of Pharmaceutical Sciences, 3500-3 Minamitamagaki-cho, Suzuka 510-0293, Japan
| | - Haruna Tsuda
- Oita University, Research Promotion Institute, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
- Oita University, Department of Applied Chemistry, Faculty of Engineering, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
| | - Tetsuro Minagawa
- Oita University, Research Promotion Institute, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
- Oita University, Department of Applied Chemistry, Faculty of Engineering, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
| | - Tamami Nonaka
- Oita University, Research Promotion Institute, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
| | - Taizo Uda
- Oita University, Research Promotion Institute, 700 Dannoharu, Oita-shi, Oita 870-1192, Japan
- Nanotechnology Laboratory, Institute of Systems, Information Technologies and Nanotechnologies (ISIT), 4-1 Kyudai-shinmachi, Fukuoka 879-5593, Japan
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Wang H, Lu M, Zhai S, Wu K, Peng L, Yang J, Xia Y. ALW peptide ameliorates lupus nephritis in MRL/lpr mice. Arthritis Res Ther 2019; 21:261. [PMID: 31791413 PMCID: PMC6889545 DOI: 10.1186/s13075-019-2038-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Accepted: 10/21/2019] [Indexed: 02/06/2023] Open
Abstract
Background Lupus nephritis (LN) is a common and serious complication of systemic lupus erythematosus. Anti-double-stranded (ds) DNA immunoglobulin G (IgG) plays a pivotal role in the pathogenesis of LN. Currently, there are various therapies for patients with LN; however, most of them are associated with considerable side effects. We confirmed previously that ALW (ALWPPNLHAWVP), a 12-amino acid peptide, inhibited the binding of polyclonal anti-dsDNA antibodies to mesangial cells and isolated glomeruli in vitro. In this study, we further investigate whether the administration of ALW peptide decreases renal IgG deposition and relevant damage in MRL/lpr lupus-prone mice. Methods Forty female MRL/lpr mice were randomly divided into four groups. The mice were intravenously injected with D-form ALW peptide (ALW group), scrambled peptide (PLP group), and normal saline (NaCl group) or were not treated (blank group). The IgG deposition, the histopathologic changes, and the expressions of profibrotic factors were analyzed in the kidney of MRL/lpr mice. Results Compared with the other groups, glomerular deposition of IgG, IgG2a, IgG2b, and IgG3 was decreased in the ALW group. Moreover, ALW administration attenuated renal histopathologic changes in MRL/lpr mice, including mesangial proliferation and infiltration of inflammatory cells. Furthermore, the expressions of profibrotic cytokines, such as transforming growth factor-beta1 (TGF-β1) and platelet-derived growth factor B (PDGF-B), decreased in the serum and kidney tissue of ALW-treated mice. Conclusions Our study demonstrated that ALW peptide ameliorates the murine model of LN, possibly through inhibiting renal IgG deposition and relevant tissue inflammation and fibrosis.
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Affiliation(s)
- Huixia Wang
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Mei Lu
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Siyue Zhai
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Kunyi Wu
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Lingling Peng
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Jie Yang
- Department of Nephrology, Tangdu Hospital, The Fourth Military Medical University, Xi'an, 710032, China.
| | - Yumin Xia
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, China.
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Wang X, Xia Y. Anti-double Stranded DNA Antibodies: Origin, Pathogenicity, and Targeted Therapies. Front Immunol 2019; 10:1667. [PMID: 31379858 PMCID: PMC6650533 DOI: 10.3389/fimmu.2019.01667] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 07/03/2019] [Indexed: 01/02/2023] Open
Abstract
Systemic lupus erythematosus (SLE) is characterized by high-titer serological autoantibodies, including antibodies that bind to double-stranded DNA (dsDNA). The origin, specificity, and pathogenicity of anti-dsDNA antibodies have been studied from a wider perspective. These autoantibodies have been suggested to contribute to multiple end-organ injuries, especially to lupus nephritis, in patients with SLE. Moreover, serum levels of anti-DNA antibodies fluctuate with disease activity in patients with SLE. By directly binding to self-antigens or indirectly forming immune complexes, anti-dsDNA antibodies can accumulate in the glomerular and tubular basement membrane. These autoantibodies can also trigger the complement cascade, penetrate into living cells, modulate gene expression, and even induce profibrotic phenotypes of renal cells. In addition, the expression of suppressor of cytokine signaling 1 is reduced by anti-DNA antibodies simultaneously with upregulation of profibrotic genes. Anti-dsDNA antibodies may even participate in the pathogenesis of SLE by catalyzing hydrolysis of certain DNA molecules or peptides in cells. Recently, anti-dsDNA antibodies have been explored in greater depth as a therapeutic target in the management of SLE. A substantial amount of data indicates that blockade of pathogenic anti-dsDNA antibodies can prevent or even reverse organ damage in murine models of SLE. This review focuses on the recent research advances regarding the origin, specificity, classification, and pathogenicity of anti-dsDNA antibodies and highlights the emerging therapies associated with them.
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Affiliation(s)
- Xiaoyu Wang
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Yumin Xia
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
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Wang H, Wang J, Xia Y. Defective Suppressor of Cytokine Signaling 1 Signaling Contributes to the Pathogenesis of Systemic Lupus Erythematosus. Front Immunol 2017; 8:1292. [PMID: 29085365 PMCID: PMC5650678 DOI: 10.3389/fimmu.2017.01292] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 09/26/2017] [Indexed: 12/19/2022] Open
Abstract
Systemic lupus erythematosus (SLE) is a complex autoimmune disease involving injuries in multiple organs and systems. Exaggerated inflammatory responses are characterized as end-organ damage in patients with SLE. Although the explicit pathogenesis of SLE remains unclear, increasing evidence suggests that dysregulation of cytokine signals contributes to the progression of SLE through the Janus kinase/signal transducer and activator of transcription (STAT) signaling pathway. Activated STAT proteins translocate to the cell nucleus and induce transcription of target genes, which regulate downstream cytokine production and inflammatory cell infiltration. The suppressor of cytokine signaling 1 (SOCS1) is considered as a classical inhibitor of cytokine signaling. Recent studies have demonstrated that SOCS1 expression is decreased in patients with SLE and in murine lupus models, and this negatively correlates with the magnitude of inflammation. Dysregulation of SOCS1 signals participates in various pathological processes of SLE such as hematologic abnormalities and autoantibody generation. Lupus nephritis is one of the most serious complications of SLE, and it correlates with suppressed SOCS1 signals in renal tissues. Moreover, SOCS1 insufficiency affects the function of several other organs, including skin, central nervous system, liver, and lungs. Therefore, SOCS1 aberrancy contributes to the development of both systemic and local inflammation in SLE patients. In this review, we discuss recent studies regarding the roles of SOCS1 in the pathogenesis of SLE and its therapeutic implications.
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Affiliation(s)
- Huixia Wang
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Jiaxing Wang
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Yumin Xia
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
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Dong Y, Zhang Y, Xia L, Wang P, Chen J, Xu M, Liu X, Xia Y. The deposition of anti-DNA IgG contributes to the development of cutaneous lupus erythematosus. Immunol Lett 2017; 191:1-9. [PMID: 28899632 DOI: 10.1016/j.imlet.2017.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Revised: 09/01/2017] [Accepted: 09/07/2017] [Indexed: 12/11/2022]
Abstract
Anti-DNA IgG is a hallmark of systemic lupus erythematosus and induces internal injuries in patients. It is known that cutaneous lupus erythematosus (CLE) involves the deposition of autoantibodies in the dermoepidermal junction of the skin and that anti-DNA IgG binds specifically to keratinocytes. However, the definite role of anti-DNA IgG in CLE remains unclear. The purpose of this study was to elucidate the effect of anti-DNA IgG on keratinocytes in CLE. Skin tissues were collected from patients with CLE and healthy controls. Also, murine anti-DNA IgG was incubated with frozen sections of murine skin or PAM212 keratinocytes. The chemotaxis of J774.2 macrophages was evaluated in special chambers with keratinocytes under anti-DNA IgG stimulation. Enzyme-linked immunosorbent assay, flow cytometry, Western blot, and surface plasmon resonance were used to quantitate the interaction between anti-DNA IgG and keratinocyte-related self-antigens. The results showed that anti-DNA IgG could be eluted from the lesional tissues of CLE patients, depending on the serum positivity. Murine anti-DNA IgG bound preferably to the dermoepidermal zones of normal skin and specifically to collagen III and the suppressor of cytokine signalling 1 (SOCS1) but not to Ro52. Moreover, the chemotaxis of macrophages was promoted by the incubation of anti-DNA IgG with keratinocytes. Interestingly, anti-DNA IgG exaggerated both the expression and the activation of fibroblast growth factor inducible 14 (Fn14) in keratinocytes and regulated SOCS1 signals in a time-dependent manner. In conclusion, anti-DNA IgG may contribute to the development of CLE through binding to keratinocyte-related antigens, exacerbating inflammatory infiltration, and modulating Fn14 and SOCS1 pathways.
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Affiliation(s)
- Yingying Dong
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710004, China
| | - Yi Zhang
- Intensive Care Unit, China Gezhouba Group Central Hospital, The Third Clinical Medical College of China Three Gorges University, Yichang, 443000, China
| | - Linlin Xia
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, 710004, China
| | - Ping Wang
- Department of Immunology & Microbiology, Wannan Medical College, Wuhu, 241001, China
| | - Jingyun Chen
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710004, China
| | - Meifeng Xu
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710004, China
| | - Xingyin Liu
- Department of Pathogenic Biology, Nanjing Medical University, Nanjing, 211166, China
| | - Yumin Xia
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an 710004, China.
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Yang D, Kroe-Barrett R, Singh S, Roberts CJ, Laue TM. IgG cooperativity - Is there allostery? Implications for antibody functions and therapeutic antibody development. MAbs 2017; 9:1231-1252. [PMID: 28812955 PMCID: PMC5680800 DOI: 10.1080/19420862.2017.1367074] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
A central dogma in immunology is that an antibody's in vivo functionality is mediated by 2 independent events: antigen binding by the variable (V) region, followed by effector activation by the constant (C) region. However, this view has recently been challenged by reports suggesting allostery exists between the 2 regions, triggered by conformational changes or configurational differences. The possibility of allosteric signals propagating through the IgG domains complicates our understanding of the antibody structure-function relationship, and challenges the current subclass selection process in therapeutic antibody design. Here we review the types of cooperativity in IgG molecules by examining evidence for and against allosteric cooperativity in both Fab and Fc domains and the characteristics of associative cooperativity in effector system activation. We investigate the origin and the mechanism of allostery with an emphasis on the C-region-mediated effects on both V and C region interactions, and discuss its implications in biological functions. While available research does not support the existence of antigen-induced conformational allosteric cooperativity in IgGs, there is substantial evidence for configurational allostery due to glycosylation and sequence variations.
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Affiliation(s)
- Danlin Yang
- a Biotherapeutics Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield , Connecticut , USA
| | - Rachel Kroe-Barrett
- a Biotherapeutics Discovery Research, Boehringer Ingelheim Pharmaceuticals, Inc. , Ridgefield , Connecticut , USA
| | - Sanjaya Singh
- b Janssen BioTherapeutics, Janssen Research & Development, LLC, Spring House , Pennsylvania , USA
| | - Christopher J Roberts
- c Department of Chemical and Biomolecular Engineering , University of Delaware , Newark , Delaware , USA
| | - Thomas M Laue
- d Department of Molecular, Cellular, and Biomedical Sciences , University of New Hampshire , Durham , New Hampshire , USA
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Wang P, Yang J, Tong F, Duan Z, Liu X, Xia L, Li K, Xia Y. Anti-Double-Stranded DNA IgG Participates in Renal Fibrosis through Suppressing the Suppressor of Cytokine Signaling 1 Signals. Front Immunol 2017; 8:610. [PMID: 28620377 PMCID: PMC5449454 DOI: 10.3389/fimmu.2017.00610] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2017] [Accepted: 05/09/2017] [Indexed: 12/21/2022] Open
Abstract
Suppressor of cytokine signaling 1 (SOCS1) participates in renal fibrosis by downregulating Janus kinase 2 (JAK2)/signal transducer and activator of transcription 1 (STAT1)-mediated cytokine signaling. Recently, it was found that anti-double-stranded DNA (dsDNA) IgG induces the synthesis of profibrotic cytokines by renal cells. To explore the potential effect of anti-dsDNA IgG on SOCS1-mediated renal fibrosis, kidney tissues were collected from patients with lupus nephritis (LN) as well as MRL/lpr lupus-prone mice. The SOCS1 expression was evaluated in tissue samples. In addition, SCID mice were injected with anti-dsDNA IgG, followed by evaluation of SOCS1 levels. Renal resident cells were cultured in vitro, receiving the stimulation of anti-dsDNA IgG and then the measurement of SOCS1, JAK2, STAT1α, and profibrotic cytokines. Moreover, the binding of anti-dsDNA IgG to SOCS1 kinase inhibitory region (KIR) peptide was analyzed by surface plasmon resonance. We found that SOCS1 expression was inhibited, but JAK2/STAT1 activation was prominent in the kidney tissues of patients with LN, MRL/lpr mice, or anti-dsDNA IgG-injected SCID mice. The cultured renal cells also showed SOCS1 downregulation, JAK2/STAT1 activation, and profibrotic cytokine promotion upon anti-dsDNA IgG stimulation. Surprisingly, anti-dsDNA IgG showed high affinity to KIR peptide and competed with JAK2 loop for KIR. Additionally, a DNA-mimicking peptide (ALW) blocked the binding of anti-dsDNA IgG to KIR, and even partially abrogated the activation of JAK2/STAT1α signals and the expression of profibrotic cytokines in SCID mice. In conclusion, anti-dsDNA IgG downregulates SOCS1 expression, activates JAK2/STAT1 signals, and contributes to renal fibrosis; its peptide blockade may restore the SOCS1 inhibitory effect on the production of profibrotic cytokine, and finally ameliorate renal fibrosis in LN.
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Affiliation(s)
- Ping Wang
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Jie Yang
- Department of Nephrology, Tangdu Hospital, Fourth Military Medical University, Xi'an, China
| | - Fang Tong
- Department of Immunology and Microbiology, Wannan Medical College, Wuhu, China
| | - Zhaoyang Duan
- Department of Nephrology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Xingyin Liu
- Department of Pathogenic Biology, Nanjing Medical University, Nanjing, China
| | - Linlin Xia
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Ke Li
- Core Research Laboratory, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
| | - Yumin Xia
- Department of Dermatology, The Second Affiliated Hospital, School of Medicine, Xi'an Jiaotong University, Xi'an, China
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Shang C, Wang Z, Liu H. A terminal antibody method based on multiple factors that influence ELISA results for measurement of antibody affinity in clinical specimens. J Virol Methods 2016; 240:42-48. [PMID: 27889565 DOI: 10.1016/j.jviromet.2016.11.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 11/15/2016] [Accepted: 11/17/2016] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To establish a new method for the measurement of antibody affinity in clinical samples. METHODS Serial dilutions of antiserum samples were prepared to find the threshold concentration of antibody separating detectable from negative ELISA results. This threshold concentration was defined as the terminal antibody (TA) concentration, and a new method for measuring antibody affinity based on the effect of multiple factors that influence ELISA results at TA concentration was established, which we called the TA method. The TA method was used to measure low- and high-affinity antiserum samples to verify the validity of the method, and then was used to measure the affinity of the antibody to Hepatitis B surface antigen and affinity of antibody to Hepatitis C Virus in clinical serum specimens. RESULTS Low- and high-affinity antiserum samples could be clearly distinguished by TA method. The antibody affinity in anti-HBe positive group was significantly higher than that of anti-HBe negative group; the affinity of antibody to HCV in HCV-RNA negative group was significantly higher than that of HCV-RNA positive group. CONCLUSIONS The TA method for measuring antibody affinity in clinical specimens displayed its validation and that may have potential application value in clinical settings.
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Affiliation(s)
- Congcong Shang
- College of Medical Laboratory, Dalian Medical University, Dalian, China.
| | - Zhen Wang
- The First Affiliated Hospital of Dalian Medical University, Dalian, China.
| | - Hui Liu
- College of Medical Laboratory, Dalian Medical University, Dalian, China.
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Bowen A, Wear MP, Cordero RJB, Oscarson S, Casadevall A. A Monoclonal Antibody to Cryptococcus neoformans Glucuronoxylomannan Manifests Hydrolytic Activity for Both Peptides and Polysaccharides. J Biol Chem 2016; 292:417-434. [PMID: 27872188 DOI: 10.1074/jbc.m116.767582] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Indexed: 11/06/2022] Open
Abstract
Studies in the 1980s first showed that some natural antibodies were "catalytic" and able to hydrolyze peptide or phosphodiester bonds in antigens. Many naturally occurring catalytic antibodies have since been isolated from human sera and associated with positive and negative outcomes in autoimmune disease and infection. The function and prevalence of these antibodies, however, remain unclear. A previous study suggested that the 18B7 monoclonal antibody against glucuronoxylomannan (GXM), the major component of the Cryptococcus neoformans polysaccharide capsule, hydrolyzed a peptide antigen mimetic. Using mass spectrometry and Förster resonance energy transfer techniques, we confirm and characterize the hydrolytic activity of 18B7 against peptide mimetics and show that 18B7 is able to hydrolyze an oligosaccharide substrate, providing the first example of a naturally occurring catalytic antibody for polysaccharides. Additionally, we show that the catalytic 18B7 antibody increases release of capsular polysaccharide from fungal cells. A serine protease inhibitor blocked peptide and oligosaccharide hydrolysis by 18B7, and a putative serine protease-like active site was identified in the light chain variable region of the antibody. An algorithm was developed to detect similar sites present in unique antibody structures in the Protein Data Bank. The putative site was found in 14 of 63 (22.2%) catalytic antibody structures and 119 of 1602 (7.4%) antibodies with no annotation of catalytic activity. The ability of many antibodies to cleave antigen, albeit slowly, supports the notion that this activity is an important immunoglobulin function in host defense. The discovery of GXM hydrolytic activity suggests new therapeutic possibilities for polysaccharide-binding antibodies.
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Affiliation(s)
- Anthony Bowen
- From the Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Maggie P Wear
- the Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, and
| | - Radames J B Cordero
- the Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, and
| | - Stefan Oscarson
- the Centre for Synthesis and Chemical Biology, UCD School of Chemistry and Chemical Biology, University College Dublin, Belfield, Dublin 4, Ireland
| | - Arturo Casadevall
- the Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland 21205, and
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