A KDEL‐tagged monoclonal antibody is efficiently retained in the endoplasmic reticulum in leaves, but is both partially secreted and sorted to protein storage vacuoles in seeds

• DOI: 10.1111/j.1467-7652.2006.00200.x
• Publication Date: 2006-06-06T12:48:02Z
• Authors: Silvana Petruccelli; Marisa S. Otegui; Fabricio Lareu; Olivia Tran Dinh; Anne‐Catherine Fi...; Ariana Circosta; Martin Rumbo; Muriel Bardor; Rosa Carcamo; Véronique Gomord; Roger N. Beachy
• Keywords: KDEL; Endoplasmic-reticulum-associated protein degradation

Transgenic plants are attractive biological systems for the large-scale production of pharmaceutical proteins. In particular, seeds offer special advantages, such as ease handling and long-term stable storage. Nevertheless, most studies expression antibodies in have been performed leaves. We report a secreted (sec-Ab) or KDEL-tagged (Ab-KDEL) mutant 14D9 monoclonal antibody transgenic tobacco leaves seeds. Although KDEL sequence has little effect on accumulation leaves, it leads to higher yield sec-Ab(Leaf) purified from leaf contains complex N-glycans, including Lewis(a) epitopes, typically found extracellular glycoproteins. contrast, Ab-KDEL(Leaf) bears only high-mannose-type oligosaccharides (mostly Man 7 8) consistent with an efficient endoplasmic reticulum (ER) retention/cis-Golgi retrieval antibody. sec-Ab Ab-KDEL gamma chains cleaved by proteases contain N-glycans indicating maturation late Golgi compartments. Consistent glycosylation protein, Ab-KDEL(Seed) was partially sorted protein storage vacuoles (PSVs) not ER. This dual targeting may be due KDEL-mediated PSV partial saturation vacuolar sorting machinery. Taken together, our results reveal important differences ER retention machinery between addition, we demonstrate that plant-made triantennary similar Fab functionality its counterpart biantennary but former interacts A stronger manner is more immunogenic than latter. Such could related variable immunoglobulin G (IgG)-Fc folding would depend size N-glycan.