Fc fragment with antigen-binding (Fcab) is a novel construct which can be selected to recognize specifically a wide variety of target proteins. We describe the selection and affinity maturation of Fcab clones targeting VEGF, an important pro-angiogenesis factor. To investigate the extent of engineering permissible to Fcabs we applied targeted mutagenesis to all three C-terminal loop structures and the C-terminus of the CH3 domain to isolate high-affinity binders by directed evolution and yeast display. The matured clone, CT6, binds to VEGF with low nanomolar affinity and inhibits VEGF-stimulated proliferation of human umbilical vein endothelial cells in vitro. Molecular dynamics simulations were performed to address flexibility of the molecular structure of CT6 and to approximate a structural ensemble in aqueous solution. Significantly higher RMSF levels of CT6 in comparison to wild-type Fc were limited to the elongated CD-loop in the CH3 domain, while the overall structural integrity was retained. This allowed the Fcab to replace the Fc portion of a mAb, in which both the CH3 and Fab are capable of antigen engagement: a construct called mAb2 was assembled with CT6 and the Fab of bevacizumab. This bispecific molecule showed more potent antagonistic activity than bevacizumab in vitro. Further evaluation for the potential of the CT6 Fcab in targeted therapy is warranted due to the possibility of being combined with other therapeutically meaningful targets.
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http://dx.doi.org/10.1093/protein/gzx042 | DOI Listing |
Cell Host Microbe
December 2024
Cancer Center, The First Hospital of Jilin University, Changchun, Jilin 130021, China; Institute of Virology and AIDS Research, The First Hospital of Jilin University, Changchun, Jilin 130021, China; Institute of Translational Medicine, Key Laboratory of Organ Regeneration and Transplantation of Ministry of Education, The First Hospital of Jilin University, Changchun, Jilin 130021, China. Electronic address:
Enterovirus D68 (EV-D68) is a leading non-polio enterovirus that causes severe respiratory diseases and poliomyelitis-like illness in children. Viral entry represents a potential multifaceted target for antiviral intervention; however, there are no approved inhibitors to block EV-D68. Here, we identify the functionally undescribed membrane protein major facilitator superfamily-domain-containing protein 6 (MFSD6) as an EV-D68 entry factor amenable to therapeutic intervention.
View Article and Find Full Text PDFCell Metab
December 2024
Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Vascular Homeostasis and Remodeling, Peking University, Beijing, China. Electronic address:
Immunoglobulin G (IgG) is traditionally recognized as a plasma protein that neutralizes antigens for immune defense. However, our research demonstrates that IgG predominantly accumulates in adipose tissue during obesity development, triggering insulin resistance and macrophage infiltration. This accumulation is governed by neonatal Fc receptor (FcRn)-dependent recycling, orchestrated in adipose progenitor cells and macrophages during the early and late stages of diet-induced obesity (DIO), respectively.
View Article and Find Full Text PDFJ Am Soc Mass Spectrom
January 2025
Michael Barber Centre for Collaborative Mass Spectrometry, MBCCMS, Princess Street, Manchester M17DN, U.K.
Post expression from the host cells, biotherapeutics undergo downstream processing steps before final formulation. Mass spectrometry and biophysical characterization methods are valuable for examining conformational and stoichiometric changes at these stages, although typically not used in biomanufacturing, where stability is assessed via bulk property studies. Here we apply hybrid MS methods to understand how solution condition changes impact the structural integrity of a biopharmaceutical across the processing pipeline.
View Article and Find Full Text PDFImmunol Rev
November 2024
IMGT®, the international ImMunoGeneTics information system® (IMGT), Laboratoire d'ImmunoGénétique Moléculaire (LIGM), Institut de Génétique Humaine (IGH), UMR 9002 Centre National de la Recherche Scientifique (CNRS), Université de Montpellier (UM), Montpellier Cedex 5, France.
Immunol Rev
November 2024
Immune Therapies Group, Burnet Institute, Melbourne, Victoria, Australia.
Advances in antibody engineering are being directed at the development of next generation immunotherapeutics with improved potency. Hexamerisation of IgG is a normal physiological aspect of IgG biology and recently described mutations that facilitate this process have a substantial impact upon monoclonal antibody behavior resulting in the elicitation of dramatically enhanced complement-dependent cytotoxicity, Fc receptor function, and enhanced antigen binding effects, such as targeted receptor agonism or microbe neutralization. Whereas the discovery of IgG hexamerisation enhancing mutations has largely focused on residues with exposure at the surface of the Fc-Fc and CH2-CH3 interfaces, our unique approach is the engineering of the mostly buried residue H429 in the CH3 domain.
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