title: Antibody-antigen kinetics constrain intracellular humoral immunity.
abstract: During infection with non-enveloped viruses, antibodies stimulate immunity from inside cells by activating the cytosolic Fc receptor TRIM21. This intracellular humoral response relies on opsonized viral particles reaching the cytosol intact but the antigenic and kinetic constraints involved are unknown. We have solved the structure of a potent TRIM21-dependent neutralizing antibody in complex with human adenovirus 5 hexon and show how these properties influence immune activity. Structure-guided mutagenesis was used to generate antibodies with 20,000-fold variation in affinity, on-rates that differ by ~50-fold and off-rates by >175-fold. Characterization of these variants during infection revealed that TRIM21-dependent neutralization and NFκB activation was largely unaffected by on-rate kinetics. In contrast, TRIM21 antiviral activity was exquisitely dependent upon off-rate, with sub-μM affinity antibodies nevertheless unable to stimulate signaling because of fast dissociation kinetics. These results define the antibody properties required to elicit an efficient intracellular immune response during viral infection.
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge, CB2 0QH, United Kingdom.
authors.forename: Maria
authors.initials: M
authors.lastname: Bottermann
authors.affiliation: Centre for Immune Regulation, Department of Biosciences, University of Oslo, N-0371 Oslo, Norway.|Centre for Immune Regulation, Department of Immunology, Oslo University Hospital Rikshospitalet, University of Oslo, N-0424 Oslo, Norway.
authors.forename: Heidrun Elisabeth
authors.initials: HE
authors.lastname: Lode
authors.affiliation: Icahn School of Medicine, Mount Sinai, New York, USA.
authors.forename: Ruth E
authors.initials: RE
authors.lastname: Watkinson
authors.affiliation: Centre for Immune Regulation, Department of Biosciences, University of Oslo, N-0371 Oslo, Norway.|Centre for Immune Regulation, Department of Immunology, Oslo University Hospital Rikshospitalet, University of Oslo, N-0424 Oslo, Norway.
authors.forename: Stian
authors.initials: S
authors.lastname: Foss
authors.affiliation: Centre for Immune Regulation, Department of Biosciences, University of Oslo, N-0371 Oslo, Norway.|Centre for Immune Regulation, Department of Immunology, Oslo University Hospital Rikshospitalet, University of Oslo, N-0424 Oslo, Norway.
authors.forename: Inger
authors.initials: I
authors.lastname: Sandlie
authors.affiliation: Centre for Immune Regulation, Department of Biosciences, University of Oslo, N-0371 Oslo, Norway.|Centre for Immune Regulation, Department of Immunology, Oslo University Hospital Rikshospitalet, University of Oslo, N-0424 Oslo, Norway.
authors.forename: Jan Terje
authors.initials: JT
authors.lastname: Andersen
authors.affiliation: Medical Research Council Laboratory of Molecular Biology, Division of Protein and Nucleic Acid Chemistry, Francis Crick Avenue, Cambridge, CB2 0QH, United Kingdom.
authors.forename: Leo C
authors.initials: LC
authors.lastname: James
mesh_terms: D000260:Adenoviruses, Human / Q000737:chemistry* / Q000254:growth & development / Q000276:immunology; D057134:Antibodies, Neutralizing / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D000915:Antibody Affinity; D000956:Antigens, Viral / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D001665:Binding Sites; D003001:Cloning, Molecular; D018360:Crystallography, X-Ray; D015870:Gene Expression; D005822:Genetic Vectors / Q000737:chemistry / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D056724:Immunity, Humoral / Q000187:drug effects*; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D007700:Kinetics; D008958:Models, Molecular; D016328:NF-kappa B / Q000494:pharmacology; D009500:Neutralization Tests; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D015202:Protein Engineering; D054730:Protein Interaction Domains and Motifs; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D012261:Ribonucleoproteins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D013329:Structure-Activity Relationship; D000099207:SS-A Antigen
chemical_list: D057134:Antibodies, Neutralizing; D000956:Antigens, Viral; D007140:Immunoglobulin Fab Fragments; D016328:NF-kappa B; D011994:Recombinant Proteins; D012261:Ribonucleoproteins; D000099207:SS-A Antigen