Rice against cholera
The first "edible" cholera vaccine was created on the basis of GM rice
Japanese molecular biologists have developed the first edible cholera vaccine based on genetically modified rice grains and successfully tested its safety on volunteers. This was announced on Saturday by the press service of the University of Tokyo with reference to an article in the journal Lancet Microbe (Yuki et al., Oral MucoRice-CTB vaccine for safety and microbiota-dependent immunogenicity in humans: a phase 1 randomized trial – VM).
"The results of our first experiments made me very optimistic about the future of our vaccine. The immunity of the volunteers reacted to small, medium, and large doses of the vaccine, each time increasing the strength of their reaction to the proteins of the cholera vibrio," said Hiroshi Kiyeno, a professor at the University of Tokyo (Japan), whose words are quoted by the press service of the university.
According to WHO, about 1.3-4 million people are infected with cholera every year, and about 20-140 thousand more die from infection, the source of which is usually contaminated food or water. As a rule, most cases of cholera infection occur in developing countries in Asia and Africa. Existing cholera vaccines protect the human body for only a few years, and at the same time they work extremely poorly when injected into the body of young children, especially vulnerable to cholera.
Professor Hiroshi Kiyeno and his colleagues have taken a big step towards solving this problem by developing the first full-fledged "edible" cholera vaccine, for the storage, production and use of which no special conditions are required.
At its core, it is a powder of ground grains of genetically modified rice. In its genome, scientists have embedded a fragment of the DNA of the vibrio cholera, which is responsible for the production of certain segments of the CTB protein, the main toxin of this bacterium.
Long-lasting edible vaccine
This substance, as experiments with blood samples of people who have had cholera have shown, causes a strong immune reaction and causes their body to produce a large number of antibodies capable of connecting with the shell of the cholera vibrio.
Guided by this idea, Japanese scientists modified the rice genome in such a way that the plant began to accumulate a large number of fragments of CTB protein in fatty inclusions inside the protein part of rice grains. These proteins, as Professor Kieno notes, act as a protective shell that allows the toxin fragments to reach the intestinal mucosa, where they are captured by immune cells.
Scientists tested the work of the vaccine on six dozen volunteers, half of whom received a real vaccine, and the rest – a solution of ordinary rice flour seasoned with salt. Subsequent observations showed that the vaccine did not cause any adverse reactions and led to the formation of a large number of antibodies in two-thirds of the volunteers.
The immunity of the remaining 30% reacted relatively weakly to the vaccine, which biologists associate with differences in the state of the microflora of volunteers. In particular, the scientists found that the vaccination was noticeably more active on those participants of the experiment whose microflora was distinguished by a high species diversity.
Professor Kieno and his colleagues plan to test this theory during the subsequent phases of clinical trials of the vaccine, which will involve significantly more volunteers. Their completion, scientists hope, will lead to the emergence of cheap and at the same time effective vaccination against cholera.
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