Recently, Japanese researchers developed a new vaccine against cholera. It is not a vaccine requiring injections, since it is taken orally. However, the latter has a particularity:it "grows" in transgenic rice.
The perspective of drinking a liquid rather than getting injected with a vaccine is a rather appealing idea. However, in a press release published on June 26, 2021, researchers from the University of Tokyo (Japan) explained that they had developed a new oral vaccine against cholera, it is MucoRice-CTB, obtained from GMO rice. It should be remembered in passing that cholera is a disease discovered in 1854 that still causes around 100,000 deaths each year for nearly 4 million cases due to the bacterium Vibrio cholerae .
You should know that there are already four oral vaccines against this disease, the administration of which is in the form of drops to be placed on the tongue. Nevertheless, these are made from strains of Vibrio cholerae attenuated dead. Thus, they require cold storage. These vaccines can also cause side effects such as nausea, fatigue or abdominal pain. MucoRice-CTB remains stable at room temperature . Very easy to use, it comes in the form of a powder to be diluted in water.
This Japanese vaccine "grows" in genetically modified short-grain rice plants. This produces a non-toxic portion of the B subunit (CTB) from seeds. The immune system recognizes CTBs, accumulating in protein bodies, these cell organists surrounded by a membrane. Thus, it is a question of a kind of "natural capsule" intended for the protection of the antigen of the enzymes digestive. In addition, precautions are taken in the context of the cultivation of this GMO rice. In fact, the plants are indoors, integrating into hydroponic production in order to avoid any environmental contamination.
You should know that no vaccine against cholera is absolutely effective. However, MucoRice-CTB is no exception to this trend. As project director Hiroshi Kiyono points out, the vaccine uses the intestinal immune system to produce more antibodies. When the intestinal mucous membranes are exposed to the vaccine, they produce specific IgG and IgA antibodies , whereas a vaccine injected into a muscle produces only IgG.
The vaccine allowed a majority of the thirty volunteers for the experiment to develop IgG and IgA after a duration of two and four months following ingestion . However, the researchers found a weak or no immune response in eleven of these patients. Thus, it may well be that each individual's gut microbiota interacts differently with the vaccine. A more diversified microbiota would be synonymous with better immune response in the presence of the vaccine. However, this is not very surprising since the disparity in immune responses is the main problem facing scientists making oral vaccines.
