Japanese researchers develop rice strain that works as oral vaccine against cholera

Researchers primarily from the University of Tokyo's Institute of Medical Science (IMSUT) have developed a rice strain packed with a protein that protects against cholera symptoms, including diarrhea.

Cholera is mostly spread by ingesting water contaminated with the cholera bacillus and through undercooked seafood.

The disease affects up to 4 million people each year, with up to 140,000 deaths, mainly from developing nations.

While oral cholera vaccines are available, there are obstacles to widespread use, such as refrigeration requirements.

Researchers from IMSUT led by immunology professor Hiroshi Kiyono developed a genetically modified rice plant strain purposely designed to generate part of a protein used by the intestinal tract for cholera toxin absorption.

They also set their sights on developing rice that can be stored at room temperature.

The rice strain grains are ideal as a vaccine when pulverized and mixed into a physiological saline solution.

Its key ingredient creates antibodies when absorbed by the intestinal tract.

It was also discovered that the larger the dose of the vaccine, the more antibodies were generated.

The researchers first verified the safety and effectiveness of the oral vaccine in mice, pigs, and monkeys before conducting clinical trials on 60 adult males at the IMSUT Hospital in 2015 and 2016.

They are now hoping to collaborate with a business group to conduct additional clinical trials.

The researchers are currently growing the rice strain at the IMSUT complex in Tokyo's Shirokanedai district. They also plan to work with Chiba University and other entities to grow the rice strain in larger volumes.