Albumin, antibodies and T-cell receptors - Sandlie

The Sandlie group studied the structure and function of antibodies and T-cell receptors, the specific detection molecules of the adaptive immune system. The purpose of the work was to engineer antibodies and other molecules for use in therapy and research.

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My research group has studied structure and function of antibodies and T-cell receptors and engineered these specific immune system detectors for use in therapy and as research tools. I am particularly interested in the interaction of both molecules with their specific receptors. Furthermore, my research group unraveled how albumin and IgG share an intracellular receptor, FcRn, that regulates the serum half-life and biodistribution of both.

I received my PhD from the University of Bergen in 1981 in the field of DNA and nucleotide synthesis. I then held postdoctoral positions at Johns Hopkins University and the Radium Hospital in Oslo, where I started my studies of antibody structure and function. I joined UiO in 1988, first as assistant professor in Molecular Biology and then, in 1995, as full professor. From 2007-2017 I was deputy director of the Centre for Immune Regulation, a Centre of Excellence appointed by the Research Council of Norway and held a position as senior researcher at Oslo University Hospital (OUH). 2017-2020, I was deputy director of a Federation of Clinical Immunology Societies Centre of Excellence, consisting of 18 research groups located in Oslo, and president of the Norwegian Society for Immunology.

I was elected member of the Norwegian Academy of Science and Letters in 2002, and served as group leader (Cell Biology) from 2011-2019. 

I have co-authored more than 130 publications since 1988, and have received awards for scientific innovation. I am co-inventor on a number of patents describing antibody variants and ”Vaccibodies”, ”Phagemers” and the ”Veltis®” technology, and I am co-founder of several biotechnology companies: Vaccibody A/S (now Nykode A/S, Nextera A/S, Authera A/S and JTIS A/S. I have consulted for Vaccibody A/S (Norway), Albumedix A/S (UK) and for Syntimmune A/S (USA), and presently serve on the board of the technology transfer office of UiO and OUH (Inven2 A/S) and Radforsk. I am member of the Advisory Board for OUH Comprehensive Cancer Centre, Trond Mohn Stiftelse and Lund University’s board for research evaluation. Furthermore, I have served on boards at the Norwegian Research Council, consulted for the Swedish and Finnish research councils and been member of the Norwegian Biotechnology Advisory Board.

I have supervised more than 60 MSc students and 20 PhD students, and have evaluated doctoral thesis in Norway, Sweden, Switzerland and Australia. I was on a 3 months sabbatical at Brigham and Womens’s Hospital and Harvard Medical School, Boston in 2015, and at the Scripps Research Institute, La Jolla in 2016. 

Contributions to Science the last 10 years

I have published more than 130 peer-reviewed journal articles related to T cell receptor, IgG and IgG receptor biochemistry and immunology. Below is a summary of activities over the last 10 years.

Immunoreceptor engineering.

We have established a novel phage display platform, socalled Signal Sequence Independent phage display – SSIp display. The key finding is that two viral capsid proteins, pVII and pIX, display fusion proteins extremely well, and they do so without the need for translational signal sequences (Nilssen NR et al, Nucleic Acids Res 2012 and Løset GÅ et al, PLoS One 2011).  Importantly, we have found that the SSIp display phage particles can display not only antibody fragments and T cell receptors (Høydahl LS et al, Sci Reports 2016 and Gunnarsen KS et al, Sci Reports 2013), but also MHC class II peptide complexes, and we call the MHC class II displaying phages “Phagemers”. Phagemers bind to specific T cell receptors, and thus detect T cells based on this specificity. We have explored the use of Phagemers as diagnostic tools. SSIp display is the core technology of the spin-out company Nextera A/S (www.nextera.no). Nextera A/S commercializes and develops the Phagemer technology and selects binders from large phagemer libraries, the aim being target discovery for drug development.

Studies of celiac disease: Celiac disease (CD) develops in individuals with certain MHC class II types, and in particular, DQ2.5, which is characterised by its ability to bind and present modified gluten peptides on the surface of antigen presenting cells. To answer questions regarding the nature of these antigen presenting cells in the gut of CD patients, we designed antibodies that bind gluten-DQ2.5 complexes with very high specificity, using SSIp display. In collaboration with Ludvig Sollid and Frode Jahnsen’s groups, we then found the antibodies to bind B cells and plasma cells in patient biopsies.  We hypothesize that the interaction between these cells and disease-associated T cells is a key driver of disease, as the detecting antibodies also inhibit T cell activation and are drug candidates. CD patients produce autoantibodies against transglutaminase 2, the enzyme that modifies the gluten peptides. Interestingly, at least some of the gluten-DQ2.5 presenting plasma cells are transglutaminase 2 specific (Høydahl LS et al, Gastroenterology 2019 and Frick R et al, Science Immunology 2021).

The T cell response against gluten-DQ2.5 complexes is biased in CD patients, in that their T cell receptors are often composed of signature variable segment pairs selected for being particularly well suited for complex binding. In collaboration with Ludvig Sollid and Shuo Wang Qiao, we have unraveled the molecular basis for a common signature, and identified an MHC recognition motif centered on a certain amino acid residue in the T cell receptor. This one residue not only contacts MHC, but also directs a pivotal part of the T cell receptor to contact the gluten peptide (Gunnarsen KS et al, JCI Insight 2017).

Half-life of IgG antibodies and albumin fused drugs:

Most proteins in blood degrade within a few hours or days, but IgG and albumin, which are the two most abundant, are rescued from degradation and have half-lives of three weeks. This is due to the fact that they bind the neonatal Fc receptor (FcRn), and we study how FcRn binding regulates the serum half-life and biodistribution of both ligands.

The long half-life is important for the therapeutic success of IgG antibodies, and thus, there is an intense interest in increasing the strength of the FcRn interaction to prolong the half-life even further. The FcRn interaction is pH dependent, with histidine dependent strong binding at acidic pH and little or no binding at neutral pH. We have studied how FcRn binds IgG molecules of different subclasses, and found that members of the IgG3 subclass degrade faster than the others, because of a slight difference in FcRn binding kinetics (Stapleton NM et al, Nat Commun 2011).This is due to a single amino acid being arginine in IgG3 and histidine in the other subclasses. We have also engineered an IgG variant with increased binding at acidic pH, which has enhanced half-life as well as ability to activate complement (PCT/IB2017/000327). The patent was recently licensed by a large drug development company. Furthermore, the variable region may have a pronounced effect on both cellular transport and plasma half-life. The half-life of three weeks is actually an average. We recently described how charge patches in the variable region contribute by altering FcRn binding kinetics (Grevys A et al iScience 2022).

We have also unraveled the interaction between FcRn and albumin (Andersen JT et al, Nat Commun 2012). Again, it is pH and histidine dependent as well as largely hydrophobic in nature (Sand KMK et al, J Biol Chem 2014). We have designed albumin variants with increased binding to FcRn at acidic pH that have increased half-life in rodents and monkeys (Andersen JT et al, J Biol Chem 2014 and described in several patents).

Biodistribution of IgG antibodies

FcRn is expressed intracellularly, and binds IgG taken up by fluid-phase endocytosis. It can then direct monomeric IgG to the surface of the opposite side of the cell (transcytosis) or to the side of entry (recycling). We have studied both processes using the natural ligands as well as engineered variants (Foss S et al, J Control Release 2016). A new in vitro recycling assay designed by us predicts the behavior of designed FcRn-binding molecules in vivo in animal models (Grevys A et al, Nat Commun 2017). We have found that FcRn is the only Fc receptor required for transport of IgG across cellular barriers and placenta (Mathiesen L et al, Blood 2013). In collaboration with Richard Blumberg’s laboratory, we have found that it enhances antigen presentation and cross presentation of antigen in immune complexes by specialized dendritic cells (Baker K et al, Proc Natl Acad Sci 2011). Furthermore, we recently found that FcRn cooperates with FcγRIIa to regulate innate cytokine production and antigen presentation through formation of a ternary complex consisting of FcRn, FcγRIIa and IgG IC (Hubbard J et al, J Exp Med 2020).

Biodistribution of albumin and albumin fused drugs  

In collaboration with Richard Blumberg’s laboratory, we found that albumin produced in the liver is released to the bloodstream, and directed away from the bile (Pyzik M et al, Proc Natl Acad Sci 2017). 

Importantly, we recently found that albumin is transcytosed efficiently from the apical to the basolateral side of the mucosae, and think this observation holds great promise for mucosal delivery of albumin based vaccines and therapeutics (Bern M et al, J Control Release 2015 and Science Translational Med 2020).

Intracellular antiviral immunity

Antibodies are key molecules in the fight against viral infections. Although previously thought to mediate protection in the extracellular environment, research by the group of Leo James (MRC-LMB) over the last 10 years has revealed that antibody mediated protection extends to the cytosolic compartment of non-professional cells. This post-entry viral defense mechanism is mediated by the cytosolic antibody receptor tripartite motif containing 21 (TRIM21). When viral pathogens bound by antibody enter the cytosol, TRIM21 is rapidly recruited and mediates a coordinated effector response that involve degradation of the viral particle in via the proteasome and induction of innate antiviral signaling.

In close collaboration with the James group we have studies the relationship between TRIM21 effector functions and antibody affinity. We found that while TRIM21 mediates efficient neutralization under suboptimal conditions, induction of innate signaling is balanced according to the functional affinity for the incoming immune stimuli (Foss S et al., JI, 2016). This finding demonstrates that TRIM21 balances its signaling response to be proportionate to the viral treat while still being able to thwart infection. The intracellular anti-viral defense mediated by TRIM21 relies on opsonized viral particles reaching the cytosol intact. However, the antibody-antigen binding properties required to elicit an efficient intracellular immune response has been unknown. Using the co-crystal structure between a potently TRIM21-dependent neutralizing antibody and adenovirus 5 hexon, we together with the James group, used structure guided mutagenesis to generate antibodies with a wide range of affinities for the viral antigen. Using this system, we have defined the antigenic and kinetic constraints of TRIM21 function (Bottermann, M Sci Rep, 2016). Comparing the IgG subclasses for their intracellular antiviral activity, we found IgG3 to be superior, due to its long hinge region (Foss S et al, Sci Immunol, 2022).

 

Published Feb. 19, 2018 7:00 PM - Last modified Aug. 17, 2022 1:53 PM