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Amino Acids, Peptides, and Proteins | Bacteria | Bacterial Infections and Mycoses | Biological Factors | Immunotherapy


Passive immunization with antibodies is a promising approach against enterotoxigenic Escherichia coli diarrhea, a prevalent disease in LMICs. The objective of this study was to investigate expression of a monoclonal anti-ETEC CfaE secretory IgA antibody in N. benthamiana plants, with a view to facilitating access to ETEC passive immunotherapy. SIgA1 and SIgA2 forms of mAb 68-81 were produced by co-expressing the light and engineered heavy chains with J chain and secretory component in N. benthamiana. Antibody expression and assembly were compared with CHO-derived antibodies by SDS-PAGE, western blotting, size-exclusion chromatography and LC-MS peptide mapping. N-linked glycosylation was assessed by rapid fluorescence/mass spectrometry and LC-ESI-MS. Susceptibility to gastric digestion was assessed in an in vitro model. Antibody function was compared for antigen binding, a Caco-2 cell-based ETEC adhesion assay, an ETEC hemagglutination inhibition assay and a murine in vivo challenge study. SIgA1 assembly appeared superior to SIgA2 in plants. Both sub-classes exhibited resistance to degradation by simulated gastric fluid, comparable to CHO-produced 68-61 SIgA1. The plant expressed SIgAs had more homogeneous N-glycosylation than CHO-derived SIgAs, but no alteration of in vitro functional activity was observed, including antibodies expressed in a plant line engineered for mammalian-like N glycosylation. The plant-derived SIgA2 mAb demonstrated protection against diarrhea in a murine infection model. Although antibody yield and purification need to be optimized, anti-ETEC SIgA antibodies produced in a low-cost plant platform are functionally equivalent to CHO antibodies, and provide promise for passive immunotherapy in LMICs.


Enterotoxigenic Escherichia coli, Nicotiana benthamiana, immunotherapy, monoclonal antibody, passive immunization, secretory IgA

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© 2021 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Teh AY, Cavacini L, Hu Y, Kumru OS, Xiong J, Bolick DT, Joshi SB, Grünwald-Gruber C, Altmann F, Klempner M, Guerrant RL, Volkin DB, Wang Y, Ma JK. Investigation of a monoclonal antibody against enterotoxigenic Escherichia coli, expressed as secretory IgA1 and IgA2 in plants. Gut Microbes. 2021 Jan-Dec;13(1):1-14. doi: 10.1080/19490976.2020.1859813. PMID: 33439092; PMCID: PMC7833773. Link to article on publisher's site

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Gut microbes

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Creative Commons Attribution 4.0 License
This work is licensed under a Creative Commons Attribution 4.0 License.