title: Recombinant antibody 2G12 produced in maize endosperm efficiently neutralizes HIV-1 and contains predominantly single-GlcNAc N-glycans.
abstract: Antibody 2G12 is one of a small number of human immunoglobulin G (IgG) monoclonal antibodies exhibiting potent and broad human immunodeficiency virus-1 (HIV-1)-neutralizing activity in vitro, and the ability to prevent HIV-1 infection in animal models. It could be used to treat or prevent HIV-1 infection in humans, although to be effective it would need to be produced on a very large scale. We have therefore expressed this antibody in maize, which could facilitate inexpensive, large-scale production. The antibody was expressed in the endosperm, together with the fluorescent marker protein Discosoma red fluorescent protein (DsRed), which helps to identify antibody-expressing lines and trace transgenic offspring when bred into elite maize germplasm. To achieve accumulation in storage organelles derived from the endomembrane system, a KDEL signal was added to both antibody chains. Immunofluorescence and electron microscopy confirmed the accumulation of the antibody in zein bodies that bud from the endoplasmic reticulum. In agreement with this localization, N-glycans attached to the heavy chain were mostly devoid of Golgi-specific modifications, such as fucose and xylose. Surprisingly, most of the glycans were trimmed extensively, indicating that a significant endoglycanase activity was present in maize endosperm. The specific antigen-binding function of the purified antibody was verified by surface plasmon resonance analysis, and in vitro cell assays demonstrated that the HIV-neutralizing properties of the maize-produced antibody were equivalent to or better than those of its Chinese hamster ovary cell-derived counterpart.
authors.affiliation: Institute for Molecular Biotechnology, Biology VII, RWTH Aachen, Worringerweg 1, 52074 Aachen, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Rademacher
authors.forename: Markus
authors.initials: M
authors.lastname: Sack
authors.forename: Elsa
authors.initials: E
authors.lastname: Arcalis
authors.forename: Johannes
authors.initials: J
authors.lastname: Stadlmann
authors.forename: Simone
authors.initials: S
authors.lastname: Balzer
authors.forename: Friedrich
authors.initials: F
authors.lastname: Altmann
authors.forename: Heribert
authors.initials: H
authors.lastname: Quendler
authors.forename: Gabriela
authors.initials: G
authors.lastname: Stiegler
authors.forename: Renate
authors.initials: R
authors.lastname: Kunert
authors.forename: Rainer
authors.initials: R
authors.lastname: Fischer
authors.forename: Eva
authors.initials: E
authors.lastname: Stoger
mesh_terms: D000595:Amino Acid Sequence; D002853:Chromatography, Liquid; D015497:HIV-1 / Q000276:immunology*; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D009500:Neutralization Tests; D046549:Plantibodies / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D030821:Plants, Genetically Modified; D011134:Polysaccharides / Q000032:analysis*; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D003313:Zea mays / Q000235:genetics*
chemical_list: D046549:Plantibodies; D011134:Polysaccharides; D011994:Recombinant Proteins