A new innovation was carried out to develop an oral vaccine that could treat cholera, consisting of genetically engineered rice that could be consumed with water.
Researchers from the University of Tokyo developed a new kind of vaccine to treat cholera by using genetically modified rice that consists of non-toxic cholera antigens. This is a unique kind of vaccine that doesn’t require refrigeration and could be consumed by mixing it well with water. The vaccine has cholera toxin subunit B (CTB) that acts as cholera antigen to enhance immunity and prevent cholera infection. It involved genetically engineered short-grain rice that is grinded and mixed well with water. As the vaccine is orally consumed, the protein in rice stored in its protein membrane protects cholera antigens in vaccine from digestive enzymes that would usually destroy orally delivered vaccines. The vaccine was named as MucoRice-CTB.
The trials were initiated on humans to test the vaccine. The first phase 1 human trial was performed with 4 groups of 10 volunteers. Each volunteer were given 4 doses of vaccine over 8 weeks. After the trial, it was reported that there were no such side effects of the vaccine; however the responses of volunteers were distinct depending upon individual immune efficiency. Most of the volunteers responded positively to the vaccine. However, around one-third of the volunteer among total cohort showed minimal immune responses after vaccine.
Each individual responded differently after the vaccination. The efficacy of vaccine is depended upon composition of individual gut microbiome. The only factor for distinct responses of an individual to vaccine is microbial diversity. Each individual possess diverse gut microbiome. The higher responders to the vaccine possess more diversified microbiome as compared to the lower responders who had less diversified microbiome. Researchers speculated that more diversity in gut microbiome may create better situation for antigens to give strong immunity responses as compared to the lower one.