UMMS Affiliation

Department of Medicine, Division of Infectious Diseases and Immunology

Publication Date


Document Type



Bacteria | Bacterial Infections and Mycoses | Immunology of Infectious Disease | Immunotherapy | Microbiology


Novel therapeutics against the global threat of multidrug-resistant Neisseria gonorrhoeae are urgently needed. Gonococci possess several mechanisms to evade killing by human complement, including binding of factor H (FH), a key inhibitor of the alternative pathway. FH comprises 20 short consensus repeat (SCR) domains organized in a head-to-tail manner as a single chain. N. gonorrhoeae binds two regions in FH; domains 6 and 7 and domains 18 through 20. We designed a novel anti-infective immunotherapeutic molecule that fuses domains 18-20 of FH containing a D-to-G mutation in domain 19 at position 1119 (called FH*) with human IgG1 Fc. FH*/Fc retained binding to gonococci but did not lyse human erythrocytes. Expression of FH*/Fc in tobacco plants was undertaken as an alternative, economical production platform. FH*/Fc was expressed in high yields in tobacco plants (300-600 mg/kg biomass). The activities of plant- and CHO-cell produced FH*/Fc against gonococci were similar in vitro and in the mouse vaginal colonization model of gonorrhea. The addition of flexible linkers [e.g., (GGGGS)2 or (GGGGS)3] between FH* and Fc improved the bactericidal efficacy of FH*/Fc 2.7-fold. The linkers also improved PMN-mediated opsonophagocytosis about 11-fold. FH*/Fc with linker also effectively reduced the duration and burden of colonization of two gonococcal strains tested in mice. FH*/Fc lost efficacy: i) in C6(-/-) mice (no terminal complement) and ii) when Fc was mutated to abrogate complement activation, suggesting that an intact complement was necessary for FH*/Fc function in vivo. In summary, plant-produced FH*/Fc represent promising prophylactic or adjunctive immunotherapeutics against multidrug-resistant gonococci.


Fc fusion protein, Neisseria gonorrhoeae, Nicotiana benthamiana, complement, factor H, factor H (FH), gonorrhea, immunotherapeutic

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Copyright © 2020 Shaughnessy, Tran, Zheng, DeOliveira, Gulati, Song, Maclean, Wycoff and Ram. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

DOI of Published Version



Shaughnessy J, Tran Y, Zheng B, DeOliveira RB, Gulati S, Song WC, Maclean JM, Wycoff KL, Ram S. Development of Complement Factor H-Based Immunotherapeutic Molecules in Tobacco Plants Against Multidrug-Resistant Neisseria gonorrhoeae. Front Immunol. 2020 Oct 26;11:583305. doi: 10.3389/fimmu.2020.583305. PMID: 33193396; PMCID: PMC7649208. Link to article on publisher's site

Journal/Book/Conference Title

Frontiers in immunology

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