Comparative analysis of plant‐produced, recombinant dimeric IgA against cell wall β‐glucan of pathogenic fungi

• Published in: Biotechnology and bioengineering Vol. 114; no. 12; pp. 2729 - 2738
• Main Authors: Capodicasa, Cristina, Catellani, Marcello, Moscetti, Ilaria, Bromuro, Carla, Chiani, Paola, Torosantucci, Antonella, Benvenuto, Eugenio
• Format: Journal Article
• Language: English
• Published: United States 01-12-2017
• Subjects: antigen binding efficiency; anti‐infectious IgA; beta-Glucans - metabolism; Candida albicans - physiology; Cell Adhesion - physiology; Dimerization; fungal infections; Immunoglobulin A - biosynthesis; Immunoglobulin A - genetics; immunotherapy; Plant Leaves - genetics; Plant Leaves - metabolism; plant pharming; recombinant IgA; Recombinant Proteins - biosynthesis; Recombinant Proteins - genetics; plant pharming; anti-infectious IgA; antigen binding efficiency; recombinant IgA; immunotherapy; fungal infections
• ISSN: 0006-3592; 1097-0290
• DOI: 10.1002/bit.26403

Immunoglobulins A (IgA) are crucially involved in protection of human mucosal surfaces from microbial pathogens. In this work, we devised and expressed in plants recombinant chimeric antifungal antibodies (Abs) of isotype A (IgA1, IgA2, and scFvFcA1), derived from a murine mAb directed to the fungal cell wall polysaccharide β‐glucan which had proven able to confer protection against multiple pathogenic fungi. All recombinant IgA (rIgA) were expressed and correctly assembled in dimeric form in plants and evaluated for yield, antigen‐binding efficiency and antifungal properties in vitro, in comparison with a chimeric IgG1 version. Production yields and binding efficiency to purified β‐glucans showed significant variations not only between Abs of different isotypes but also between the different IgA formats. Moreover, only the dimeric IgA1 was able to strongly bind cells of the fungal pathogen Candida albicans and to restrain its adhesion to human epithelial cells. Our data indicate that IgG to IgA switch and differences in molecular structure among different rIgA formats can impact expression in plant and biological activity of anti‐β‐glucans Abs and provide new insights for the design of recombinant IgA as anti‐infective immunotherapeutics, whose potential is still poorly investigated.
Immunoglobulins A are crucially involved in protection of mucosal surfaces by microbial pathogens. Starting from an IgG, dimeric IgAs targeting beta‐glucan, a cell wall polysaccharide common to fungal pathogens, were generated and produced in plants. The influence that isotype switching exerted on plant expression, antigen‐binding characteristics and antifungal properties of these antibodies was evaluated providing new insights for the design of recombinant IgA as anti‐infective immunotherapeutics.