Illustration of plants forming antibody structures.

Boosting Immunity Through Plants: A New Era of Antibody Production

Avery Sinclair in Science & Nature September 2025 • 4 min read.

"How plant-based systems are revolutionizing the creation of therapeutic antibodies against mucosal pathogens, offering scalable and cost-effective solutions."

Our immune system's front line of defense against pathogens often starts at mucosal surfaces – the linings of our respiratory, digestive, and reproductive tracts. Immunoglobulin A (IgA) plays a vital role in neutralizing these threats. In mucosal tissues, IgA is produced in a dimeric form, meaning two IgA molecules are joined together. To reach the surface, these dimeric IgA molecules need a little help from a protein called the secretory component (SC).

The secretory component (SC) binds to dimeric IgA, forming secretory IgA (SIgA). This combination enhances IgA's stability and its ability to bind to mucus, effectively trapping pathogens and preventing them from invading the body. Because of its crucial role, SIgA is being explored as a therapeutic antibody against mucosal pathogens.

Producing sufficient quantities of SIgA for research and potential therapies has been a challenge. Traditionally, SIgA has been produced using mammalian cell lines or extracted from colostrum (early milk). However, these methods are costly and difficult to scale up. That's why researchers are exploring plant expression systems as a scalable and cost-effective alternative for producing SIgA. A recent study highlights the success of using transgenic plants to produce SC, which can then bind to IgA to form functional SIgA.

Unlocking Plant Power: Producing Secretory Component (SC) in Plants

Illustration of plants forming antibody structures.

The key to plant-based SIgA production lies in efficiently creating the secretory component (SC) within plants. To do this, researchers engineered Arabidopsis thaliana plants to produce a modified version of mouse SC, called SC-KDEL. The KDEL tag ensures the protein remains within the plant cell's endoplasmic reticulum (ER), an organelle responsible for protein folding and modification. By keeping SC-KDEL in the ER, researchers aimed to boost its accumulation.

To further enhance SC-KDEL production, the researchers used a binary vector containing a translational enhancer and an efficient terminator. The results were impressive: SC-KDEL accumulated to 2.7% of the total leaf protein in these transgenic Arabidopsis plants. This high level of expression makes plants a viable source of SC for SIgA production.

Here's a breakdown of the key strategies used to achieve high SC-KDEL expression:

KDEL Tagging: Ensuring the SC protein is retained within the endoplasmic reticulum, preventing it from being transported elsewhere in the cell.
Optimized Genetic Elements: Utilizing a translational enhancer (AtADH 5'-UTR) to improve the efficiency of protein synthesis and an efficient terminator (THSP) to ensure proper gene expression.
Plant Selection: Selecting high-expressing lines of transgenic Arabidopsis to maximize SC-KDEL production.

Once the plants were successfully producing SC-KDEL, the next step was to see if it could bind with IgA to form functional SIgA. The researchers extracted SC-KDEL from the plants and mixed it with dimeric IgA produced by mouse cells. The result? The plant-derived SC-KDEL successfully bound to the mouse IgA, forming SIgA complexes.

Future of Plant-Based SIgA: A Versatile Tool for Immunotherapy

The researchers went a step further and demonstrated that the SIgA produced in plants could neutralize Shiga toxin 1 (Stx1), a dangerous toxin produced by certain bacteria. By crossing SC-KDEL-producing plants with plants expressing IgA specific for Stx1, they created plants that produced SIgA capable of blocking the toxin's activity.

This breakthrough suggests that transgenic plants expressing SC-KDEL can provide a versatile means of SIgA production, opening doors to new therapeutic strategies against mucosal pathogens. Plant-based SIgA could be used for oral passive immunotherapy, where individuals consume plant material containing the antibody to protect against infection.

While further research is needed to optimize plant-based SIgA production and assess its efficacy in vivo, this study represents a significant step forward in harnessing the power of plants for human health. Future research will focus on enhancing SIgA formation in plant cells.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1007/s00299-018-2358-6, Alternate LINK

Title: Plant-Derived Secretory Component Forms Secretory Iga With Shiga Toxin 1-Specific Dimeric Iga Produced By Mouse Cells And Whole Plants

Subject: Plant Science

Journal: Plant Cell Reports

Publisher: Springer Science and Business Media LLC

Authors: Katsuhiro Nakanishi, Shota Morikane, Nao Hosokawa, Yuka Kajihara, Kohta Kurohane, Yasuo Niwa, Hirokazu Kobayashi, Yasuyuki Imai

Published: 2018-11-30

Everything You Need To Know

What is secretory IgA (SIgA), and why is it important?

The secretory IgA (SIgA) is an antibody crucial for mucosal immunity. It functions at the front lines of defense within the mucosal surfaces of the respiratory, digestive, and reproductive tracts, which are the body's initial barrier against pathogens. SIgA neutralizes threats by binding to pathogens and preventing their invasion into the body. The production of SIgA in a dimeric form requires the presence of a secretory component (SC) to enhance its stability and ability to bind to mucus effectively. This makes SIgA a key element in protecting the body against various diseases.

Why are plants being used to produce secretory IgA (SIgA)?

Scientists are exploring plant expression systems to produce secretory IgA (SIgA) because traditional methods like using mammalian cell lines or extracting from colostrum are costly and difficult to scale up. These systems can be used to produce the secretory component (SC) within plants such as Arabidopsis thaliana, providing a scalable and cost-effective alternative for SIgA production. The research focused on engineering plants to produce SC-KDEL, a modified version of mouse SC, which can then combine with dimeric IgA to create functional SIgA.

How do scientists produce the secretory component (SC) in plants?

To produce secretory component (SC) effectively within plants, researchers engineered Arabidopsis thaliana with specific strategies. This involved using a KDEL tag to retain the SC-KDEL within the endoplasmic reticulum (ER) for optimal protein folding and accumulation. The use of optimized genetic elements such as a translational enhancer and an efficient terminator enhanced protein synthesis and expression. Furthermore, selecting high-expressing lines of transgenic Arabidopsis plants was critical in maximizing SC-KDEL production. These steps collectively enabled plants to become a viable source of SC for SIgA production.

What is the role of the secretory component (SC) in the context of this research?

The secretory component (SC) is a protein essential for the function of secretory IgA (SIgA). Secretory component binds to dimeric IgA, which is then transformed into SIgA. This transformation is crucial because it enhances IgA's stability and its ability to bind to mucus, which helps trap pathogens, thus preventing their entry into the body. Without SC, dimeric IgA would not be able to perform its protective functions effectively. The production of SC in plants provides a way to form SIgA.

What are the potential future implications of using plants to produce SIgA?

The future implications of plant-based secretory IgA (SIgA) production are significant. It offers the potential for creating versatile tools for immunotherapy. By engineering plants to produce SIgA specific to certain pathogens, such as Shiga toxin 1 (Stx1), researchers can develop treatments that neutralize harmful toxins. This approach could lead to innovative treatments against diseases and a more scalable, cost-effective method for producing therapeutic antibodies, with implications for vaccine development and overall improvements in mucosal immunity.