New COVID-19 Therapy Uses Plants

New research led by Shawn Chen, a researcher with the Arizona State University's Biodesign Center for Immunotherapy, Vaccines and Virotherapy and School of Life Sciences, describes an innovative therapy for COVID-19, using transient expression in tobacco plants to develop and produce a monoclonal antibody, or mAb. This therapy may protect against COVID-19, even as the virus attempts to evade immune detection through mutation.

Monoclonal antibodies help reduce the severity of COVID-19 by blocking the virus's entry into human cells, reducing viral load, and triggering the immune system to fight off the infection. Class 1 and 2 mAbs that are now commonly used against COVID-19 are highly potent and can neutralize a specific variant of the virus by targeting the receptor-binding domain of the SARS-CoV-2 spike protein. However, the virus can sometimes outmaneuver such therapies. Instead of binding with the ACE2 receptor-binding domain, the novel class 4 mAb in the new study targets a site that is distant from the ACE2 binding domain yet can effectively neutralize multiple variants of concern, including Omicron variants.

The treatment could be particularly useful for people with compromised immune systems and elderly patients who are highly vulnerable to SARS-CoV-2 and its emergent variants. The new therapy could also be added to existing therapies for COVID-19, significantly enhancing their protection.

COVID-19 therapies using plants have several advantages as plants can produce large quantities of therapeutic proteins in a relatively short amount of time. They are inexpensive to grow and maintain and do not host human pathogens so their use reduces the risk of contamination with infectious agents. Finally, plant-based expression systems can be rapidly reprogrammed to produce new therapeutics in response to emerging pathogens such as SARS-CoV-2, making them an attractive option for pandemic response.

For more details, read the article in ASU News.