Kine Marita Knudsen Sand

• Grevys, Algirdas; Frick, Rahel; Mester, Simone; Flem-Karlsen, Karine; Nilsen, Jeannette & Foss, Stian [Vis alle 13 forfattere av denne artikkelen] (2022). Antibody variable sequences have a pronounced effect on cellular transport and plasma half-life. iScience. 25:103746(2), s. 1–22. doi: 10.1016/j.isci.2022.103746. Fulltekst i vitenarkiv Vis sammendrag

  Monoclonal IgG antibodies are the fastest growing class of biologics, but large differences exist in their plasma half-life in humans. Thus, to design IgG antibodies with favorable pharmacokinetics, it is crucial to identify the determinants of such differences. Here, we demonstrate that the variable region sequences of IgG antibodies greatly affect cellular uptake and subsequent recycling and rescue from intracellular degradation by endothelial cells. When the variable sequences are masked by the cognate antigen, it influences both their transport behavior and binding to the neonatal Fc receptor (FcRn), a key regulator of IgG plasma half-life. Furthermore, we show how charge patch differences in the variable domains modulate both binding and transport properties and that a short plasma half-life, due to unfavorable charge patches, may partly be overcome by Fc-engineering for improved FcRn binding.

• Sand, Kine Marita Knudsen; Gruber, Michael M.; Sandlie, Inger; Mathiesen, Line; Andersen, Jan Terje & Wadsack, Christian (2022). Contribution of the ex vivo placental perfusion model in understanding transplacental immunoglobulin G transfer. Placenta. ISSN 0143-4004. 127, s. 77–87. doi: 10.1016/j.placenta.2022.07.019. Fulltekst i vitenarkiv Vis sammendrag

  Introduction The acquisition of humoral immunity in utero is essential for the fetus. The crucial protein, which is responsible for this part of immunity, is immunoglobulin-G (IgG). Immune functions of IgGs are mediated via the interaction of the crystallizable fragment (Fc) region of IgG with specific Fc γ receptors (FcγRs). However, an atypical FcγR, the neonatal Fc receptor (FcRn), is a key regulator of IgG transfer across the human placenta. During the last four decades ex vivo placental perfusion studies have contributed significantly to the study of mechanisms of IgG transfer across the multicellular placental barrier. Method A PubMed search was conducted by using specific keywords: placenta, perfusion and IgG to review manuscripts using human placental perfusion to study the transplacental transfer of IgG. Relevant studies found in reference lists of these manuscripts were also added to the review, and references were included that supported or gave nuance to the discussion of the mechanisms of IgG kinetics in the placenta. Results and Discussion We found twenty publications on the study of transplacental transfer of IgG using human ex vivo placental perfusion, by research groups with partly different settings. This review summarizes knowledge about placental IgG transfer, with a strong focus on the contributions from ex vivo placental perfusion studies.

• Merten, Hannes; Brandl, Fabian; Zimmermann, Martina; Schaefer, Jonas V.; Irpinio, Linda & Sand, Kine M.K. [Vis alle 10 forfattere av denne artikkelen] (2021). Half-life extension of efficiently produced DARPin serum albumin fusions as a function of FcRn affinity and recycling. European journal of pharmaceutics and biopharmaceutics. ISSN 0939-6411. 167, s. 104–113. doi: 10.1016/j.ejpb.2021.07.011. Fulltekst i vitenarkiv Vis sammendrag

  Serum albumin shows slow clearance from circulation due to neonatal Fc receptor (FcRn)-mediated recycling and has been used for half-life extension. We report here fusions to a high-affinity DARPin, binding to Epithelial Cell Adhesion Molecule (EpCAM). We developed a novel, efficient expression system for such fusion proteins in Pichia pastoris with titers above 300 mg/L of lab-scale shake-flask culture. Since human serum albumin (HSA) does not bind to the murine FcRn, half-lives of therapeutic candidates are frequently measured in human FcRn transgenic mice, limiting useable tumor models. Additionally, serum albumins with extended half-life have been designed. We tested HSA7, motivated by its previously claimed extraordinarily long half-life in mice, which we could not confirm. Instead, we determined a half-life of only 29 h for HSA7, comparable to MSA. The fusion of HSA7 to a DARPin showed a similar half-life. To rationalize these findings, we measured binding kinetics and affinities to murine and human FcRn. Briefly, HSA7 showed affinity to murine FcRn only in the micromolar range, comparable to MSA to its cognate murine FcRn, and an affinity in the nanomolar range only to the human FcRn. This explains the comparable half-life of MSA and HSA7 in mice, while wild-type-HSA has a half-life of only 21 h, as it does not bind the murine FcRn and is not recycled. Thus, HSA-fusions with improved FcRn-affinity, such as HSA7, can be used for preclinical experiments in mice when FcRn transgenes cannot be used, as they reflect better the complex FcRn-mediated recycling and distribution mechanisms.

• Bern, Malin C.; Nilsen, Jeannette; Ferrarese, Mattia; Sand, Kine Marita Knudsen; Gjølberg, Torleif Tollefsrud & Lode, Heidrun Elisabeth [Vis alle 24 forfattere av denne artikkelen] (2020). An engineered human albumin enhances half-life and transmucosal delivery when fused to protein-based biologics. Science Translational Medicine. ISSN 1946-6234. 12(565), s. 1–13. doi: 10.1126/scitranslmed.abb0580. Fulltekst i vitenarkiv Vis sammendrag

  Needle-free uptake across mucosal barriers is a preferred route for delivery of biologics, but the efficiency of unassisted transmucosal transport is poor. To make administration and therapy efficient and convenient, strategies for the delivery of biologics must enhance both transcellular delivery and plasma half-life. We found that human albumin was transcytosed efficiently across polarized human epithelial cells by a mechanism that depends on the neonatal Fc receptor (FcRn). FcRn also transported immunoglobulin G, but twofold less than albumin. We therefore designed a human albumin variant, E505Q/T527M/K573P (QMP), with improved FcRn binding, resulting in enhanced transcellular transport upon intranasal delivery and extended plasma half-life of albumin in transgenic mice expressing human FcRn. When QMP was fused to recombinant activated coagulation factor VII, the half-life of the fusion molecule increased 3.6-fold compared with the wild-type human albumin fusion, without compromising the therapeutic properties of activated factor VII. Our findings highlight QMP as a suitable carrier of protein-based biologics that may enhance plasma half-life and delivery across mucosal barriers.

• Nilsen, Jeannette; Trabjerg, Esben; Grevys, Algirdas; Azevedo, Claudia; Brennan, Stephen O. & Stensland, Maria [Vis alle 14 forfattere av denne artikkelen] (2020). An intact C-terminal end of albumin is required for its long half-life in humans. Communications Biology. 3(1). doi: 10.1038/s42003-020-0903-7. Fulltekst i vitenarkiv Vis sammendrag

  Albumin has an average plasma half-life of three weeks and is thus an attractive carrier to improve the pharmacokinetics of fused therapeutics. The half-life is regulated by FcRn, a cellular receptor that protects against intracellular degradation. To tailor-design the therapeutic use of albumin, it is crucial to understand how structural alterations in albumin affect FcRn binding and transport properties. In the blood, the last C-terminal residue (L585) of albumin may be enzymatically cleaved. Here we demonstrate that removal of the L585 residue causes structural stabilization in regions of the principal FcRn binding domain and reduces receptor binding. In line with this, a short half-life of only 3.5 days was measured for cleaved albumin lacking L585 in a patient with acute pancreatitis. Thus, we reveal the structural requirement of an intact C-terminal end of albumin for a long plasma half-life, which has implications for design of albumin-based therapeutics.

• Hubbard, Jonathan J.; Pyzik, Michal; Rath, Timo; Kozicky, Lisa K.; Sand, Kine Marita Knudsen & Gandhi, Amit K. [Vis alle 17 forfattere av denne artikkelen] (2020). FcRn is a CD32a coreceptor that determines susceptibility to IgG immune complex-driven autoimmunity. Journal of Experimental Medicine (JEM). ISSN 0022-1007. 217(10). doi: 10.1084/jem.20200359. Fulltekst i vitenarkiv
• Pyzik, Michal; Sand, Kine Marita Knudsen; Hubbard, Jonathan J.; Andersen, Jan Terje; Sandlie, Inger & Blumberg, Richard S. (2019). The neonatal Fc Receptor (FcRn): A misnomer? Frontiers in Immunology. 10:1540(JULY), s. 1–24. doi: 10.3389/fimmu.2019.01540. Fulltekst i vitenarkiv Vis sammendrag

  Antibodies are essential components of an adaptive immune response. Immunoglobulin G (IgG) is the most common type of antibody found in circulation and extracellular fluids. Although IgG alone can directly protect the body from infection through the activities of its antigen binding region, the majority of IgG immune functions are mediated via proteins and receptors expressed by specialized cell subsets that bind to the fragment crystallizable (Fc) region of IgG. Fc gamma (γ) receptors (FcγR) belong to a broad family of proteins that presently include classical membrane-bound surface receptors as well as atypical intracellular receptors and cytoplasmic glycoproteins. Among the atypical FcγRs, the neonatal Fc receptor (FcRn) has increasingly gained notoriety given its intimate influence on IgG biology and its ability to also bind to albumin. FcRn functions as a recycling or transcytosis receptor that is responsible for maintaining IgG and albumin in the circulation, and bidirectionally transporting these two ligands across polarized cellular barriers. More recently, it has been appreciated that FcRn acts as an immune receptor by interacting with and facilitating antigen presentation of peptides derived from IgG immune complexes (IC). Here we review FcRn biology and focus on newer advances including how emerging FcRn-targeted therapies may affect the immune responses to IgG and IgG IC.

• Nilsen, Jeannette; Bern, Malin C.; Sand, Kine Marita Knudsen; Grevys, Algirdas; Dalhus, Bjørn & Sandlie, Inger [Vis alle 7 forfattere av denne artikkelen] (2018). Human and mouse albumin bind their respective neonatal Fc receptors differently. Scientific Reports. 8:14648, s. 1–12. doi: 10.1038/s41598-018-32817-0. Fulltekst i vitenarkiv
• Grevys, Algirdas; Nilsen, Jeannette; Sand, Kine Marita Knudsen; Daba, Muluneh Bekele; Øynebråten, Inger & Bern, Malin C. [Vis alle 15 forfattere av denne artikkelen] (2018). A human endothelial cell-based recycling assay for screening of FcRn targeted molecules. Nature Communications. 9. doi: 10.1038/s41467-018-03061-x. Fulltekst i vitenarkiv Vis sammendrag

  Albumin and IgG have remarkably long serum half-lives due to pH-dependent FcRn-mediated cellular recycling that rescues both ligands from intracellular degradation. Furthermore, increase in half-lives of IgG and albumin-based therapeutics has the potential to improve their efficacies, but there is a great need for robust methods for screening of relative FcRn-dependent recycling ability. Here, we report on a novel human endothelial cell-based recycling assay (HERA) that can be used for such pre-clinical screening. In HERA, rescue from degradation depends on FcRn, and engineered ligands are recycled in a manner that correlates with their half-lives in human FcRn transgenic mice. Thus, HERA is a novel cellular assay that can be used to predict how FcRn-binding proteins are rescued from intracellular degradation.

• Foss, Stian; Grevys, Algirdas; Sand, Kine Marita Knudsen; Bern, Malin C.; Blundell, Pat & Michaelsen, Terje Einar [Vis alle 9 forfattere av denne artikkelen] (2016). Enhanced FcRn-dependent transepithelial delivery of IgG by Fc-engineering and polymerization. Journal of Controlled Release. ISSN 0168-3659. 223, s. 42–52. doi: 10.1016/j.jconrel.2015.12.033. Fulltekst i vitenarkiv
• Bern, Malin C.; Sand, Kine Marita Knudsen; Nilsen, Jeannette; Sandlie, Inger & Andersen, Jan Terje (2015). The role of albumin receptors in regulation of albumin homeostasis: Implications for drug delivery. Journal of Controlled Release. ISSN 0168-3659. 211, s. 144–162. doi: 10.1016/j.jconrel.2015.06.006. Fulltekst i vitenarkiv
• Sand, Kine Marita Knudsen; Bern, Malin C.; Nilsen, Jeannette; Noordzij, Hanna Theodora; Sandlie, Inger & Andersen, Jan Terje (2015). Unraveling the interaction between FcRn and albumin: Opportunities for design of albumin-based therapeutics. Frontiers in Immunology. 5:682. doi: 10.3389/fimmu.2014.00682. Fulltekst i vitenarkiv Vis sammendrag

  The neonatal Fc receptor (FcRn) was first found to be responsible for transporting antibodies of the immunoglobulin G (IgG) class from the mother to the fetus or neonate as well as for protecting IgG from intracellular catabolism. However, it has now become apparent that the same receptor also binds albumin and plays a fundamental role in homeostatic regulation of both IgG and albumin, as FcRn is expressed in many different cell types and organs at diverse body sites. Thus, to gain a complete understanding of the biological function of each ligand, and also their distribution in the body, an in-depth characterization of how FcRn binds and regulates the transport of both ligands is necessary. Importantly, such knowledge is also relevant when developing new drugs, as IgG and albumin are increasingly utilized in therapy. This review discusses our current structural and biological understanding of the relationship between FcRn and its ligands, with a particular focus on albumin and design of albumin-based therapeutics.

• Sand, Kine Marita Knudsen; Landsverk, Ole J. B.; Berg-Larsen, Axel; Bakke, Oddmund & Gregers, Tone Fredsvik (2014). The human-specific invariant chain isoform Iip35 modulates Iip33 trafficking and function. Immunology and Cell Biology. ISSN 0818-9641. 92(9), s. 791–798. doi: 10.1038/icb.2014.54. Fulltekst i vitenarkiv
• Sand, Kine Marita Knudsen; Bern, Malin C.; Nilsen, Jeannette; Dalhus, Bjørn; Gunnarsen, Kristin Støen & Cameron, Jason [Vis alle 10 forfattere av denne artikkelen] (2014). Interaction with both domain I and III of albumin is required for optimal pH-dependent binding to the neonatal Fc Receptor (FcRn). Journal of Biological Chemistry. ISSN 0021-9258. 289(50), s. 34583–34594. doi: 10.1074/jbc.M114.587675. Fulltekst i vitenarkiv Vis sammendrag

  Albumin is an abundant blood protein that acts as a transporter of a plethora of small molecules like fatty acids, hormones, toxins, and drugs. In addition, it has an unusual long serum half-life in humans of nearly 3 weeks, which is attributed to its interaction with the neonatal Fc receptor (FcRn). FcRn protects albumin from intracellular degradation via a pH-dependent cellular recycling mechanism. To understand how FcRn impacts the role of albumin as a distributor, it is of importance to unravel the structural mechanism that determines pH-dependent binding. Here, we show that although the C-terminal domain III (DIII) of human serum albumin (HSA) contains the principal binding site, the N-terminal domain I (DI) is important for optimal FcRn binding. Specifically, structural inspection of human FcRn (hFcRn) in complex with HSA revealed that two exposed loops of DI were in proximity with the receptor. To investigate to what extent these contacts affected hFcRn binding, we targeted selected amino acid residues of the loops by mutagenesis. Screening by in vitro interaction assays revealed that several of the engineered HSA variants showed decreased binding to hFcRn, which was also the case for two missense variants with mutations within these loops. In addition, four of the variants showed improved binding. Our findings demonstrate that both DI and DIII are required for optimal binding to FcRn, which has implications for our understanding of the FcRn-albumin relationship and how albumin acts as a distributor. Such knowledge may inspire development of novel HSA-based diagnostics and therapeutics. This research was originally published in: Journal of Biological Chemistry. © the American Society for Biochemistry and Molecular Biology.

• Waelchli, Sebastien; Kumari, Shraddha; Fallang, Lars-Egil; Sand, Kine Marita Knudsen; Yang, Weiwen & Landsverk, Ole J. B. [Vis alle 9 forfattere av denne artikkelen] (2014). Invariant chain as a vehicle to load antigenic peptides on human MHC class I for cytotoxic T-cell activation. European Journal of Immunology. ISSN 0014-2980. 44(3), s. 774–784. doi: 10.1002/eji.201343671. Fulltekst i vitenarkiv
• Sand, Kine Marita Knudsen; Dalhus, Bjørn; Christianson, Gregory J.; Bern, Malin C.; Foss, Stian & Cameron, Jason [Vis alle 11 forfattere av denne artikkelen] (2014). Dissection of the neonatal Fc receptor (FcRn)-albumin interface using mutagenesis and anti-FcRn albumin-blocking antibodies. Journal of Biological Chemistry. ISSN 0021-9258. doi: 10.1074/jbc.M113.522565. Fulltekst i vitenarkiv
• Sand, Kine Marita Knudsen; Bern, Malin C.; Nilsen, Jeannette; Dalhus, Bjørn; Gunnarsen, Kristin Støen & Cameron, Jason [Vis alle 10 forfattere av denne artikkelen] (2014). Interaction with both domain I and III of albumin is required for optimal pH-dependent binding to the neonatal Fc Receptor (FcRn). Journal of Biological Chemistry. ISSN 0021-9258. 289(50), s. 34583–34594. doi: 10.1074/jbc.M114.587675. Fulltekst i vitenarkiv
• Sand, Kine Marita Knudsen; Dalhus, Bjørn; Christianson, Gregory J.; Bern, Malin C.; Foss, Stian & Cameron, Jason [Vis alle 11 forfattere av denne artikkelen] (2014). Dissection of the neonatal Fc receptor (FcRn)-albumin interface using mutagenesis and anti-FcRn albumin-blocking antibodies. Journal of Biological Chemistry. ISSN 0021-9258. 289(24), s. 17228–17239. doi: 10.1074/jbc.M113.522565. Fulltekst i vitenarkiv Vis sammendrag

  Albumin is the most abundant protein in blood and plays a pivotal role as a multitransporter of a wide range of molecules such as fatty acids, metabolites, hormones, and toxins. In addition, it binds a variety of drugs. Its role as distributor is supported by its extraordinary serum half-life of 3 weeks. This is related to its size and binding to the cellular receptor FcRn, which rescues albumin from intracellular degradation. Furthermore, the long half-life has fostered a great and increasing interest in utilization of albumin as a carrier of protein therapeutics and chemical drugs. However, to fully understand how FcRn acts as a regulator of albumin homeostasis and to take advantage of the FcRn-albumin interaction in drug design, the interaction interface needs to be dissected. Here, we used a panel of monoclonal antibodies directed towards human FcRn in combination with site-directed mutagenesis and structural modeling to unmask the binding sites for albumin blocking antibodies and albumin on the receptor, which revealed that the interaction is not only strictly pH-dependent, but predominantly hydrophobic in nature. Specifically, we provide mechanistic evidence for a crucial role of a cluster of conserved tryptophan residues that expose a pH-sensitive loop of FcRn, and identify structural differences in proximity to these hot spot residues that explain divergent cross-species binding properties of FcRn. Our findings expand our knowledge of how FcRn is controlling albumin homeostasis at a molecular level, which will guide design and engineering of novel albumin variants with altered transport properties. This research was originally published in: Journal of Biological Chemistry. © the American Society for Biochemistry and Molecular Biology.

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• Sand, Kine Marita Knudsen; Landsverk, Ole J. B.; Bakke, Oddmund & Gregers, Tone Fredsvik (2012). Intracellular trafficking of the human invariant chain isoforms, Iip33 and Iip35. Molecular Immunology. ISSN 0161-5890. 51(1), s. 30–30. doi: 10.1016/j.molimm.2012.02.081. Fulltekst i vitenarkiv
• Sand, Kine Marita Knudsen; Bakke, Oddmund & Gregers, Tone Fredsvik (2011). The Role of li p35 in MHC Class II Antigen Presentation. Scandinavian Journal of Immunology. ISSN 0300-9475. 73(4), s. 358–358. Fulltekst i vitenarkiv

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