Japanese Pharma Subsidiary's Plant-Based COVID Vaccine Nears Production

A biopharmaceutical company is seeking approval in Canada for the world's first plant-based COVID-19 vaccine, sparking hopes for mass production in the near term, Tomoko Mimata reported for Mainichi Japan.

Photo Insert: A look inside the Medicago labs

The vaccine employs the mechanism of having plants create virus-like particles (VLPs), which are extracted from the crops grown in greenhouses and presented as antigens. If the plant-derived vaccine for human use, currently under research and development by Medicago Inc., a Canadian subsidiary of Japan's Mitsubishi Tanabe Pharma Corp., is put to practical use, it will be the world's first such vaccine.

VLPs are created from plants by using Nicotiana benthamiana plants, a species that is a close relative of tobacco and has quick growth. The genetic information of coronavirus spike proteins is implemented into the plants and temporary genetic engineering takes place. The genetic information is then decoded within the leaves' cells, creating protein that accumulates as VLPs.

The final phase of clinical trials was finished last year in six countries, and according to the firm, their results showed the vaccine had 71% efficacy. In Canada, the company filed an application in December for the vaccine's authorization and aims to start distribution by the end of March.

Clinical trials are also being carried out in Japan. There are plans to file an application for pharmaceutical approval with Japan's Ministry of Health, Labor and Welfare this spring, with the goal of putting the vaccines to practical use within fiscal 2022.

Vaccines contain pathogens, parts of them, or other substances to induce an immune response against infectious diseases in the body. Medicago's vaccine is one type of VLP vaccine, which administers VLPs to the human body as antigens. The VLPs, created through the genetic engineering of organisms, have an external structure mimicking that of viruses, as well as an identical size.

Hen's eggs, E. coli bacteria, and insect cells, among other objects, have been used to manufacture VLP vaccines. Viruses have a basic structure of DNA or RNA, constituting genetic information, surrounded by a protein shell.

The coronavirus and influenza virus have a lipid membrane as its external layer, or viral envelope, and spike proteins protrude from them. As VLPs' size and external structure are almost identical to that of viruses, they are promising as highly effective vaccine antigens.

Meanwhile, as they do not hold genetic material inside, there are no concerns of viruses proliferating in the body after vaccination. This VLP vaccine technology has already been used for HPV, which is a cause of cervical cancer, by using insect cells and yeast.

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