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End-to-end approach for the characterization and control of product-related impurities in T cell bispecific antibody preparations. Int J Pharm X 2023; 5:100157. [PMID: 36687375 PMCID: PMC9850176 DOI: 10.1016/j.ijpx.2023.100157] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 12/23/2022] [Accepted: 01/01/2023] [Indexed: 01/04/2023] Open
Abstract
Antibody-based T cell-activating biologics are promising therapeutic medicines being developed for a number of indications, mainly in the oncology field. Among those, T cell bispecific antibodies are designed to bind one tumor-specific antigen and the T cell receptor at the same time, leading to a robust T cell response against the tumor. Although their unique format and the versatility of the CrossMab technology allows for the generation of safer molecules in an efficient manner, product-related variants cannot be completely avoided. Therefore, it is of extreme importance that both a manufacturing process that limits or depletes product-related impurities, as well as a thorough analytical characterization are in place, starting from the development of the manufacturing cell line until the assessment of potential toxicities. Here, we describe such an end-to-end approach to minimize, quantify and control impurities and -upon their functional characterization- derive specifications that allow for the release of clinical material.
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Key Words
- Antibody manufacturing process
- CE-SDS, capillary electrophoresis‑sodium dodecyl sulfate
- CRS, cytokine release syndrome
- ELISA, enzyme-linked immunosorbent assay
- End-to-end approach
- Fc, fragment crystallizable
- Functional characterization
- GMP, good manufacturing process
- HIC, hydrophobic interaction chromatography
- HMW, high molecular weight (species)
- IEX, ion exchange chromatography
- PBS, phosphate buffer saline
- Product-related impurities control
- SEC, size-exclusion chromatography
- SPR, surface plasmon resonance
- TAA, tumor-associated antigen
- TCB, T cell bispecific
- TCR, T cell receptor
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2
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Irisin supports integrin-mediated cell adhesion of lymphocytes. Biochem Biophys Rep 2021; 26:100977. [PMID: 33732908 PMCID: PMC7944048 DOI: 10.1016/j.bbrep.2021.100977] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/22/2021] [Accepted: 02/26/2021] [Indexed: 01/13/2023] Open
Abstract
Irisin, a myokine released from skeletal muscle, has recently been found to act as a ligand for the integrins αVβ5, αVβ1, and α5β1 expressed on mesenchymal cells, thereby playing an important role in the metabolic remodeling of the bone, skeletal muscle and adipose tissues. Although the immune-modulatory effects of irisin in chronic inflammation have been documented, its interactions with lymphocytic integrins have yet to be elucidated. Here, we show that irisin supports the cell adhesion of human and mouse lymphocytes. Cell adhesion assays using a panel of inhibitory antibodies to integrins have shown that irisin-mediated lymphocyte adhesion involves multiple integrins including not only α4β1 and α5β1, but also leukocyte-specific αLβ2 and α4β7. Importantly, mouse lymphocytic TK-1 cells that lack the expression of β1 integrins have exhibited αLβ2- and α4β7-mediated cell adhesion to irisin. Irisin has also been demonstrated to bind to purified recombinant integrin αLβ2 and α4β7 proteins. Thus, irisin represents a novel ligand for integrin αLβ2 and α4β7, capable of supporting lymphocyte cell adhesion independently of β1 integrins. These results suggest that irisin may play an important role in regulating lymphocyte adhesion and migration in the inflamed vasculature. Irisin, a myokine released from skeletal muscle, binds to integrins αLβ2 and α4β7 in addition to integrins α4β1 and α5β1. Irisin acts as an integrin ligand capable of supporting cell adhesion of human and mouse lymphocytes. The results of this study significantly expand upon the role of irisin as a contributor to metabolic regulation. Irisin deposited on the inflamed vasculature may participate in the metabolic regulation of lymphocyte migration.
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Bispecific antibodies with Fab-arms featuring exchanged antigen-binding constant domains. Biochem Biophys Rep 2021; 26:100959. [PMID: 33718630 PMCID: PMC7920882 DOI: 10.1016/j.bbrep.2021.100959] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 12/16/2020] [Accepted: 02/16/2021] [Indexed: 12/27/2022] Open
Abstract
Monoclonal antibodies can acquire the property of engagement of a second antigen via fusion methods or modification of their CDR loops, but also by modification of their constant domains, such as in the mAb2 format where a set of mutated amino acid residues in the CH3 domains enables a high-affinity specific interaction with the second antigen. We tested the possibility of introducing multiple binding sites for the second antigen by replacing the Fab CH1/CL domain pair with a pair of antigen-binding CH3 domains in a model scaffold with trastuzumab variable domains and VEGF-binding CH3 domains. Such bispecific molecules were produced in a “Fab-like” format and in a full-length antibody format. Novel constructs were of expected molecular composition using mass spectrometry. They were expressed at a high level in standard laboratory conditions, purified as monomers with Protein A and gel filtration and were of high thermostability. Their high-affinity binding to both target antigens was retained. Finally, the Her2/VEGF binding domain-exchanged bispecific antibody was able to mediate a potentiated surface Her2-internalization effect on the Her2-overexpressing cell line SK-BR-3 due to improved level of cross-linking with the endogenously secreted cytokine. To conclude, bispecific antibodies with Fabs featuring exchanged antigen-binding CH3 domains offer an alternative solution in positioning and valency of antigen binding sites. Fab constant domains can be efficiently exchanged for antigen-binding CH3 domains. Such mutagenesis results in bispecific antibodies with correct chain pairing. Domain-exchanged bispecific Fab- and IgG-like formats are of favorable biophysical properties. Resulting bispecific antibodies show high-affinity binding to both target antigens.
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Key Words
- Ab, antibody
- BLI, biolayer interferometry
- BSA, bovine serum albumin
- Bispecific antibody
- CDR, complementarity determining region
- DSC, differential scanning calorimetry
- Domain-exchanged antibody
- EC50, half-maximal effective concentration
- FBS, fetal bovine serum
- FITC, fluorescein isothiocyanate
- Fab constant domain exchange
- Fab, fragment antigen binding
- Fc, fragment crystallizable
- Fcab, Fc with antigen binding properties
- HPLC-SEC, high pressure liquid chromatography-size exclusion chromatography
- Her2 internalization
- IgG, immunoglobulin G
- LC-ESI-MS, liquid chromatography-electrospray ionization-mass spectrometry
- PBS, phosphate buffered saline
- PE, phycoerythrin
- PEI, polyethylenimine
- PNGase F, Peptide:N-glycosidase F
- RMSD, root mean square deviation
- TRA, trastuzumab
- Tm, melting temperature
- VEGF, vascular endothelial growth factor
- “Knobs-into-holes” heterodimerization
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Cross-Linking GPVI-Fc by Anti-Fc Antibodies Potentiates Its Inhibition of Atherosclerotic Plaque- and Collagen-Induced Platelet Activation. JACC Basic Transl Sci 2016; 1:131-142.. [PMID: 27766315 PMCID: PMC5063538 DOI: 10.1016/j.jacbts.2016.03.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/08/2016] [Indexed: 10/26/2022]
Abstract
To enhance the antithrombotic properties of recombinant glycoprotein VI fragment crystallizable (GPVI-Fc), the authors incubated GPVI-Fc with anti-human Fc antibodies to cross-link the Fc tails of GPVI-Fc. Cross-linking potentiated the inhibition of human plaque- and collagen-induced platelet aggregation by GPVI-Fc under static and flow conditions without increasing bleeding time in vitro. Cross-linking with anti-human-Fc Fab2 was even superior to anti-human-Fc immunoglobulin G (IgG). Advanced optical imaging revealed a continuous sheath-like coverage of collagen fibers by cross-linked GPVI-Fc complexes. Cross-linking of GPVI into oligomeric complexes provides a new, highly effective, and probably safe antithrombotic treatment as it suppresses platelet GPVI-plaque interaction selectively at the site of acute atherothrombosis.
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Comparison of methods for the analysis of therapeutic immunoglobulin G Fc-glycosylation profiles-Part 2: Mass spectrometric methods. MAbs 2016; 7:732-42. [PMID: 25996192 PMCID: PMC4622708 DOI: 10.1080/19420862.2015.1045173] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To monitor the Fc glycosylation of therapeutic immunoglobulin G in bioprocess development, product characterization and release analytics, reliable techniques for glycosylation analysis are needed. Several analytical methods are suitable for this application. We recently presented results comparing detection methods for glycan analysis that are separation-based, but did not include mass spectrometry (MS). In the study reported here, we comprehensively compared MS-based methods for Fc glycosylation profiling of an IgG biopharmaceutical. A therapeutic antibody reference material was analyzed 6-fold on 2 different days, and the methods investigated were compared with respect to precision, accuracy, throughput and analysis time. Emphasis was put on the detection and quantitation of sialic acid-containing glycans. Eleven MS methods were compared to hydrophilic interaction liquid chromatography of 2-aminobenzamide labeled glycans with fluorescence detection, which served as a reference method and was also used in the first part of the study. The methods compared include electrospray MS of the heavy chain and Fc part after limited digestion, liquid chromatography MS of a tryptic digest, porous graphitized carbon chromatography MS of released glycans, electrospray MS of glycopeptides, as well as matrix assisted laser desorption ionization MS of glycans and glycopeptides. Most methods showed excellent precision and accuracy. Some differences were observed with regard to the detection and quantitation of low abundant glycan species like the sialylated glycans and the amount of artefacts due to in-source decay.
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Key Words
- 2-AB, 2-aminobenzamide
- CE, capillary electrophoresis
- ESI-MS
- ESI-MS, electrospray ionization-mass spectrometry
- Fab, fragment antigen-binding
- Fc, fragment crystallizable
- HILIC-UHPLC, hydrophilic interaction liquid chromatography-ultra high performance liquid chromatography
- HILIC-UPLC
- HPAEC-PAD, high-performance anion exchange chromatography with pulsed amperometric detection
- IdeS protease, proteolytic enzyme like protease from Streptococcus pyrogenes
- IgG glycosylation
- IgG, immunoglobulin G
- LC-MS
- LCMS, liquid chromatography-mass spectrometry
- MALDI, matrix assisted laser desorption ionization
- MALDI-MS
- PGC-MS, porous graphitized carbon chromatography- mass spectrometry
- PNGase F, Peptide-N-Glycosidase F
- RP-HPLC, reversed phase high performance liquid chromatography
- TIC, total ion chromatogram
- glycan analysis
- mAb, monoclonal antibody
- mass spectrometry
- method comparison
- monoclonal antibody (mAb)
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A tetravalent bispecific TandAb (CD19/CD3), AFM11, efficiently recruits T cells for the potent lysis of CD19(+) tumor cells. MAbs 2016; 7:584-604. [PMID: 25875246 DOI: 10.1080/19420862.2015.1029216] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
To harness the potent tumor-killing capacity of T cells for the treatment of CD19(+) malignancies, we constructed AFM11, a humanized tetravalent bispecific CD19/CD3 tandem diabody (TandAb) consisting solely of Fv domains. The molecule exhibits good manufacturability and stability properties. AFM11 has 2 binding sites for CD3 and 2 for CD19, an antigen that is expressed from early B cell development through differentiation into plasma cells, and is an attractive alternative to CD20 as a target for the development of therapeutic antibodies to treat B cell malignancies. Comparison of the binding and cytotoxicity of AFM11 with those of a tandem scFv bispecific T cell engager (BiTE) molecule targeting the same antigens revealed that AFM11 elicited more potent in vitro B cell lysis. Though possessing high affinity to CD3, the TandAb mediates serial-killing of CD19(+) cells with little dependence of potency or efficacy upon effector:target ratio, unlike the BiTE. The advantage of the TandAb over the BiTE was most pronounced at lower effector:target ratios. AFM11 mediated strictly target-dependent T cell activation evidenced by CD25 and CD69 induction, proliferation, and cytokine release, notwithstanding bivalent CD3 engagement. In a NOD/scid xenograft model, AFM11 induced dose-dependent growth inhibition of Raji tumors in vivo, and radiolabeled TandAb exhibited excellent localization to tumor but not to normal tissue. After intravenous administration in mice, half-life ranged from 18.4 to 22.9 h. In a human ex vivo B-cell chronic lymphocytic leukemia study, AFM11 exhibited substantial cytotoxic activity in an autologous setting. Thus, AFM11 may represent a promising therapeutic for treatment of CD19(+) malignancies with an advantageous safety risk profile and anticipated dosing regimen.
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Key Words
- ALL
- AUCtot, total area under the curve
- B-ALL, B-precursor acute lymphoblastic leukemia
- BBB, blood-brain barrier
- BiTE, bispecific T cell engager
- CAR, chimeric antigen receptor
- CCS, cell culture supernatant
- CD, cluster of differentiation
- CD3
- CDR, complementarity determining region
- CHO, Chinese hamster ovary
- CL, clearance
- CLL, chronic lymphocytic leukemia
- CNS, central nervous system
- Cmax, maximal concentration
- DMSO, dimethyl sulfoxide
- E:T, effector:target
- EC50, half maximal effective concentration
- ECL, electrochemiluminescence
- F, fluorescence
- FACS, fluorescence-activated cell sorting
- FCS, fetal calf serum
- FR, framework region
- Fab, fragment antigen-binding
- Fc, fragment crystallizable
- FcRn, neonatal Fc receptor
- FcgR, Fc gamma receptor
- Fv, variable fragment
- HMF, high molecular weight forms
- HSA, human serum albumin
- His, histidine
- IFN, interferon
- IL, interleukin
- IgG, immunoglobulin G
- KD, dissociation constant
- LMF, low molecular weight forms
- MSD, MesoScale Discovery
- MWCO, molecular weight cut-off
- NHL, non-Hodgkin lymphoma
- NK, natural killer
- NOD/scid, nonobese diabetic/severe combined immunodeficiency
- Non-Hodgkin lymphoma
- ORR, overall response rate
- PBMC, peripheral blood mononuclear cell
- PBS, phosphate buffered saline
- PES, polyethersulfone
- PHA, phytohemagglutinin
- PI, propidium iodide
- SABC, standardized antibody binding capacity
- SD, standard deviation
- SDS-PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis
- SE-HPLC, size exclusion high-pressure liquid chromatography
- SEC, size exclusion chromatography
- SPR, surface plasmon resonance
- T cells
- TNF, tumor necrosis factor
- TandAb, tandem diabody
- VH, variable heavy
- VL, variable light
- Vss, volume of distribution at steady state
- WBA, whole body autoradiography
- bispecific antibodies
- ctrl., control
- i.v., intravenous
- ka, association rate constant
- kd, dissociation rate constant
- s.c., subcutaneous
- scFv, single-chain variable fragment
- t1/2, terminal elimination half-life
- w/o, without
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Abstract
Macrophages are innate immune cells that derive from circulating monocytes, reside in all tissues, and participate in many states of pathology. Macrophages play a dichotomous role in cancer, where they promote tumor growth but also serve as critical immune effectors of therapeutic antibodies. Macrophages express all classes of Fcγ receptors, and they have immense potential to destroy tumors via the process of antibody-dependent phagocytosis. A number of studies have demonstrated that macrophage phagocytosis is a major mechanism of action of many antibodies approved to treat cancer. Consequently, a number of approaches to augment macrophage responses to therapeutic antibodies are under investigation, including the exploration of new targets and development of antibodies with enhanced functions. For example, the interaction of CD47 with signal-regulatory protein α (SIRPα) serves as a myeloid-specific immune checkpoint that limits the response of macrophages to antibody therapies, and CD47-blocking agents overcome this barrier to augment phagocytosis. The response of macrophages to antibody therapies can also be enhanced with engineered Fc variants, bispecific antibodies, or antibody-drug conjugates. Macrophages have demonstrated success as effectors of cancer immunotherapy, and further investigation will unlock their full potential for the benefit of patients.
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Key Words
- ADC, antibody-drug conjugate
- ADCC, antibody-dependent cell-mediated cytotoxicity
- ADCP
- ADCP, antibody-dependent cellular phagocytosis
- AML, acute myelogenous leukemia
- BTK, Bruton's tyrosine kinase
- CD, cluster of differentiation
- CD47
- CLL, chronic lymphocytic leukemia
- EGFR, epidermal growth factor receptor
- Fc receptor
- Fc, fragment crystallizable
- FcγR, Fcγ receptors
- GM-CSF, granulocyte-macrophage colony stimulating factor
- HER2, human epidermal growth factor receptor 2
- HSC, haematopoietic stem cell
- ITAM, immunoreceptor tyrosine-based activation motif
- ITIM, immunoreceptor tyrosine-based inhibitory motif
- IgG, immunoglobulin G
- M-CSF, macrophage colony stimulating factor
- NK, natural killer
- SHP, Src homology 2 domain-containing phosphatase
- SIRPα
- SIRPα, signal-regulatory protein α
- antibodies
- cancer
- immune checkpoint
- immunotherapy
- macrophages
- phagocytosis
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Abstract
Anifrolumab (anifrolumab) is an antagonist human monoclonal antibody that targets interferon α receptor 1 (IFNAR1). Anifrolumab has been developed to treat autoimmune diseases and is currently in clinical trials. To decipher the molecular basis of its mechanism of action, we engaged in multiple epitope mapping approaches to determine how it interacts with IFNAR1 and antagonizes the receptor. We identified the epitope of anifrolumab using enzymatic fragmentation, phage-peptide library panning and mutagenesis approaches. Our studies revealed that anifrolumab recognizes the SD3 subdomain of IFNAR1 with the critical residue R279. Further, we solved the crystal structure of anifrolumab Fab to a resolution of 2.3 Å. Guided by our epitope mapping studies, we then used in silico protein docking of the anifrolumab Fab crystal structure to IFNAR1 and characterized the corresponding mode of binding. We find that anifrolumab sterically inhibits the binding of IFN ligands to IFNAR1, thus blocking the formation of the ternary IFN/IFNAR1/IFNAR2 signaling complex. This report provides the molecular basis for the mechanism of action of anifrolumab and may provide insights toward designing antibody therapies against IFNAR1.
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Key Words
- APBS, Adaptive Poisson-Boltzmann Solver
- BSA, bovine serum albumin
- CDR, complementarity-determining region
- CHARMm, Chemistry at HARvard Macromolecular Mechanics
- CHO, Chinese hamster ovary
- EDTA, ethylene diamine tetra-acetic acid
- ELISA, enzyme-linked immunosorbant assay
- FBS, fetal bovine serum
- Fab, fragment antigen-binding
- Fc, fragment crystallizable
- IFN, interferon
- IFNAR1
- IFNAR1, interferon alpha receptor 1
- IFNAR2, interferon alpha receptor 2
- IgG, immunoglobulin
- KD, equilibrium dissociation constant
- L-Cys, L-cysteine
- MEDI546
- MEMα, minimum essential alpha
- MLE, murine lung epithelial
- PBS, phosphate buffered saline
- PBST, phosphate buffered saline tablets
- PCR, polymerase chain reaction
- PDB, protein data bank
- PVDF, polyvinylidene difluoride
- Ph.D., phage display
- PyMOL, python-enhanced molecular graphics tool
- RDOCK, rigid-body docking algorithm
- RU, resonance units
- SDS–PAGE, sodium dodecyl sulfate polyacrylamide gel electrophoresis
- SPR, surface plasmon resonance
- VH, variable heavy
- VL, variable light
- ZDOCK, rigid-body docking algorithm
- anifrolumab
- enzymatic fragmentation
- epitope mapping
- kDa, kilodaltons
- mutagenesis
- phage-peptide display
- protein docking
- systemic sclerosis
- Å, ångström
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Rational design of viscosity reducing mutants of a monoclonal antibody: hydrophobic versus electrostatic inter-molecular interactions. MAbs 2015; 7:212-30. [PMID: 25559441 DOI: 10.4161/19420862.2014.985504] [Citation(s) in RCA: 73] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
High viscosity of monoclonal antibody formulations at concentrations ≥100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption.
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Key Words
- APR, Aggregation Prone Region
- ASA, Accessible Surface Area
- ASAFv-HPH, hydrophilic accessible surface area of the Fv portion
- ASAFv-HYD, hydrophobic accessible surface area of the Fv portion
- CE, Capillary Electrophoresis
- CH2
- CH3, third constant domain in heavy chain
- CHO, Chinese Hamster Ovary
- D0, diffusion coefficient at infinite dilution
- DFv, dipole moment of Fv
- DLS, Dynamic Light Scattering
- ELISA, Enzyme-Linked Immunosorbent Assay
- Fab, fragment antigen binding
- Fc, fragment crystallizable
- Fv, fragment variable
- HC, heavy chain
- IgG, immunoglobulin G
- LC, light chain
- MAB 1 Control, MAB 1 expressed in CHO cells
- MD, molecular dynamics
- NTU, Nephelometric Turbidity Unit
- PEG, polyethylene glycol
- Pagg-VH, aggregation propensity of VH domain
- Pagg-VL, aggregation propensity of VL domain
- RPM, revolutions per minute
- SE-HPLC, Size Exclusion High Performance Liquid Chromatography
- Tm, thermal transition temperature
- VH, variable domain in the heavy chain
- VL, variable domain in the light chain
- ZDHH, Debye-Huckel Henry Charge
- ZFv, net charge of the Fv
- ZFv-app, apparent charge of the Fv
- aggregation prone regions
- cIEF, capillary Isoelectric Focusing
- cP, centipoise
- high concentration
- kD, protein-protein interaction parameter
- mAb, monoclonal antibody
- molecular modeling
- monoclonal antibodies
- negatively charged patches
- rational design
- second constant domain in the heavy chain
- solubility
- viscosity
- ΔGFv, change in Free energy of Fv
- η, solution viscosity
- η0, solvent viscosity
- ηrel, relative viscosity
- ξFv, zeta-potential of the Fv
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Abstract
Bispecific antibodies have emerged in recent years as a promising field of research for therapies in oncology, inflammable diseases, and infectious diseases. Their capability of dual target recognition allows for novel therapeutic hypothesis to be tested, where traditional mono-specific antibodies would lack the needed mode of target engagement. Among extremely diverse architectures of bispecific antibodies, knobs-into-holes (KIHs) technology, which involves engineering CH3 domains to create either a “knob” or a “hole” in each heavy chain to promote heterodimerization, has been widely applied. Here, we describe the use of a cell-free expression system (Xpress CF) to produce KIH bispecific antibodies in multiple scaffolds, including 2-armed heterodimeric scFv-KIH and one-armed asymmetric BiTE-KIH with tandem scFv. Efficient KIH production can be achieved by manipulating the plasmid ratio between knob and hole, and further improved by addition of prefabricated knob or hole. These studies demonstrate the versatility of Xpress CF in KIH production and provide valuable insights into KIH construct design for better assembly and expression titer.
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Key Words
- BiTE, bispecific T-cell engager
- BiTE-KIH
- CHO, Chinese hamster ovary
- ELISA, enzyme-linked immunosorbent assay
- EpCAM, epithelial cell adhesion molecule
- FACS, fluorescence-activated cell sorting
- Fab, antigen-binding fragment
- Fc, fragment crystallizable
- FcR, Fc receptor
- HC, immunoglobulin heavy chain
- HER2, human epidermal growth factor receptor 2
- IgG, immunoglobulin G
- KIH, knob-into-hole
- LC, immunoglobulin light chain
- LC-MS, liquid chromatography-mass spectrometry
- PK, pharmacokinetics
- bispecific antibody
- cell-free protein expression
- knob-into-hole
- prefabrication
- scFv, single-chain fragment variable
- scFv-KIH
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Comparison of methods for the analysis of therapeutic immunoglobulin G Fc-glycosylation profiles--part 1: separation-based methods. MAbs 2015; 7:167-79. [PMID: 25524468 PMCID: PMC4623496 DOI: 10.4161/19420862.2014.986000] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Immunoglobulin G (IgG) crystallizable fragment (Fc) glycosylation is crucial for antibody effector functions, such as antibody-dependent cell-mediated cytotoxicity, and for their pharmacokinetic and pharmacodynamics behavior. To monitor the Fc-glycosylation in bioprocess development, as well as product characterization and release analytics, reliable techniques for glycosylation analysis are needed. A wide range of analytical methods has found its way into these applications. In this study, a comprehensive comparison was performed of separation-based methods for Fc-glycosylation profiling of an IgG biopharmaceutical. A therapeutic antibody reference material was analyzed 6-fold on 2 different days, and the methods were compared for precision, accuracy, throughput and other features; special emphasis was placed on the detection of sialic acid-containing glycans. Seven, non-mass spectrometric methods were compared; the methods utilized liquid chromatography-based separation of fluorescent-labeled glycans, capillary electrophoresis-based separation of fluorescent-labeled glycans, or high-performance anion exchange chromatography with pulsed amperometric detection. Hydrophilic interaction liquid chromatography-ultra high performance liquid chromatography of 2-aminobenzamide (2-AB)-labeled glycans was used as a reference method. All of the methods showed excellent precision and accuracy; some differences were observed, particularly with regard to the detection and quantitation of minor glycan species, such as sialylated glycans.
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Key Words
- 2-AB labeling
- 2-AB, 2-aminobenzamide
- ANTS, 8-aminonaphthalene-1, 3, 6-trisulfonate
- APTS labeling
- APTS, 8-aminopyrene-1, 3, 6-trisulfonic acid
- CCGE, cartridge-based capillary gel electrophoresis
- CE-LIF
- CE-LIF, capillary electrophoresis-laser induced fluorescence
- CHO, Chinese hamster ovary
- DNA analyzer
- DSA-FACE, DNA-sequencer-aided fluorophore-assisted carbohydrate electrophoresis
- ESI-MS, electrospray ionization-mass spectrometry
- Fab, fragment, antigen-binding
- Fc, fragment crystallizable
- HILIC-UPLC
- HILIC-UPLC, hydrophilic interaction liquid chromatography-ultra high performance liquid chromatography
- HPAEC
- HPAEC-PAD, high-performance anion exchange chromatography with pulsed amperometric detection
- HPLC, high performance liquid chromatography
- HR, high resolution
- IAB, InstantAB labeling
- IgG glycosylation
- IgG, immunoglobulin G
- MALDI-MS, matrix-assisted laser desorption/ionization-mass spectrometry
- glycan analysis
- high-throughput
- mAb, monoclonal antibody
- method comparison
- monoclonal antibody (mAb)
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Abstract
In order to treat Toll like receptor 4 (TLR4)-mediated diseases, we generated a potent antagonistic antibody directed against human TLR4, Hu 15C1. This antibody's potency can be modulated by engaging not only TLR4 but also Fcγ receptors (FcγR), a mechanism that is driven by avidity and not cell signaling. Here, using various formats of the antibody, we further dissect the relative contributions of the Fv and Fc portions of Hu 15C1, discovering that the relationship to potency of the different antibody arms is not linear. First, as could be anticipated, we observed that Hu 15C1 co-engages up to 3 receptors on the same plasma membrane, i.e., 2 TLR4 molecules (via its variable regions) and either FcγRI or FcγRIIA (via the Fc). The Kd of these interactions are in the nM range (3 nM of the Fv for TLR4 and 47 nM of the Fc for FcγRI). However, unexpectedly, neutralization experiments revealed that, due to the low level of cell surface TLR4 expression, the avidity afforded by engagement through 2 Fv arms was significantly limited. In contrast, the antibody's neutralization capacity increases by 3 logs when able to exploit Fc-FcγR interactions. Taken together, these results demonstrate an unforeseen level of contribution by FcγRs to an antibody's effectiveness when targeting a cell surface protein of relatively low abundance. These findings highlight an exploitable mechanism by which FcγR-bearing cells may be more powerfully targeted, envisioned to be broadly applicable to other reagents aimed at neutralizing cell surface targets on cells co-expressing FcγRs.
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Key Words
- DAMP, damage-associated molecular pattern
- Fc gamma receptors
- Fc, fragment crystallizable
- FcγR, Fc gamma receptor
- Fv, fragment variable
- IL, interleukin
- IVIg, intravenous immunoglobulin
- Ig, immunoglobulin
- LPS, lipopolysaccharide
- PAMP, pathogen-associated molecular pattern
- TLR, Toll-like receptor
- TLR4
- affinity maturation
- antibody
- avidity
- mAb, monoclonal antibody
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