Abstract
Shiga toxin is a major virulence factor of food-poisoning caused by Escherichia coli such as O157:H7. Secretory immunoglobulin (Ig) A (SIgA) is supposed to prevent infection of the mucosal surface and is a candidate agent for oral immunotherapy. We previously established a recombinant monoclonal antibody (mAb) consisting of variable regions from a mouse IgG mAb specific for the binding subunit of Shiga toxin 1 (Stx1) and the Fc region of mouse IgA. Here we produced a secretory form of the recombinant IgA (S-hyIgA) with transgenic Arabidopsis thaliana plant. All the S-hyIgA cDNAs (heavy, light, J chain and secretory component) were expressed under the control of a bidirectional promoter of a chlorophyll a/b-binding protein of A. thaliana without using a viral promoter. The plant-based S-hyIgA exhibited antigen binding, and was modified with plant-specific N-linked sugar chains. The Ig heavy chain and secretory components were observed in an intracellular protein body-like structure of the transgenic leaves on immuno-electron microscopy. An extract of the transgenic leaves neutralized the cytotoxicity of Stx1 toward butyrate-treated Caco-2 cells, a human colon carcinoma cell line. These results will contribute to the development of edible therapeutic antibodies such as those for the treatment of mucosal infection.
Highlights
The intestinal mucosal surface is always exposed to many types of antigens derived from food, exogenous microbes and enteric bacteria
The transcription of the H and L chain genes is controlled by a chlorophyll a/b-binding protein (CAB) promoter derived from A. thaliana, whereas the J chain gene is controlled by the cauliflower mosaic virus 35S promoter
We developed hybrid-IgG/immunoglobulin A (IgA) transgenic plants that express a secretory form of hybrid-IgG/IgA (S-hyIgA) only using the CAB promoter and terminators through a one-step transformation of four genes in a construct
Summary
The intestinal mucosal surface is always exposed to many types of antigens derived from food, exogenous microbes and enteric bacteria. Plant expression systems will be valuable for the production of SIgA and other agents aiming at oral passive immunity. The dimeric hybrid-IgG/IgA expressed in Chinese hamster ovary cells together with mouse J chain efficiently neutralized Stx[1] toxicity in vitro. We established transgenic Arabidopsis thaliana expressing the dimeric hybrid-IgG/IgA, and found that a leaf extract was capable of neutralizing Stx[1] toxicity in vitro[25]. In this transgenic plant, the transcription of the H and L chain genes is controlled by a chlorophyll a/b-binding protein (CAB) promoter derived from A. thaliana, whereas the J chain gene is controlled by the cauliflower mosaic virus 35S promoter. We examined the protein assembly of the secretory form of IgA in leaf tissues and its neutralizing activity against Stx[1] in vitro
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
