Scientists Are Growing an Edible Cholera Vaccine in Rice
The world's attention has been focused on the coronavirus crisis but Yemen, Bangladesh and many others countries in Asia and Africa are also in the grips of another pandemic: cholera. The current cholera pandemic first emerged in the 1970s and has devastated many communities in low-income countries. Each year, cholera is responsible for an estimated 1.3 million to 4 million cases and 21,000 to 143,000 deaths worldwide.
Immunologist Hiroshi Kiyono and his team at the University of Tokyo hope they can be part of the solution: They're making a cholera vaccine out of rice.
"It is much less expensive than a traditional vaccine, by a long shot."
Cholera is caused by eating food or drinking water that's contaminated by the feces of a person infected with the cholera bacteria, Vibrio cholerae. The bacteria produces the cholera toxin in the intestines, leading to vomiting, diarrhea and severe dehydration. Cholera can kill within hours of infection if it if's not treated quickly.
Current cholera vaccines are mainly oral. The most common oral are given in two doses and are made out of animal or insect cells that are infected with killed or weakened cholera bacteria. Dukoral also includes cells infected with CTB, a non-harmful part of the cholera toxin. Scientists grow cells containing the cholera bacteria and the CTB in bioreactors, large tanks in which conditions can be carefully controlled.
These cholera vaccines offer moderate protection but it wears off relatively quickly. Cold storage can also be an issue. The most common oral vaccines can be stored at room temperature but only for 14 days.
"Current vaccines confer around 60% efficacy over five years post-vaccination," says Lucy Breakwell, who leads the U.S. Centers for Disease Control and Prevention's cholera work within Global Immunization Division. Given the limited protection, refrigeration issue, and the fact that current oral vaccines require two disease, delivery of cholera vaccines in a campaign or emergency setting can be challenging. "There is a need to develop and test new vaccines to improve public health response to cholera outbreaks."
A New Kind of Vaccine
Kiyono and scientists at Tokyo University are creating a new, plant-based cholera vaccine dubbed MucoRice-CTB. The researchers genetically modify rice so that it contains CTB, a non-harmful part of the cholera toxin. The rice is crushed into a powder, mixed with saline solution and then drunk. The digestive tract is lined with mucosal membranes which contain the mucosal immune system. The mucosal immune system gets trained to recognize the cholera toxin as the rice passes through the intestines.
The cholera toxin has two main parts: the A subunit, which is harmful, and the B subunit, also known as CTB, which is nontoxic but allows the cholera bacteria to attach to gut cells. By inducing CTB-specific antibodies, "we might be able to block the binding of the vaccine toxin to gut cells, leading to the prevention of the toxin causing diarrhea," Kiyono says.
Kiyono studies the immune responses that occur at mucosal membranes across the body. He chose to focus on cholera because he wanted to replicate the way traditional vaccines work to get mucosal membranes in the digestive tract to produce an immune response. The difference is that his team is creating a food-based vaccine to induce this immune response. They are also solely focusing on getting the vaccine to induce antibodies for the cholera toxin. Since the cholera toxin is responsible for bacteria sticking to gut cells, the hope is that they can stop this process by producing antibodies for the cholera toxin. Current cholera vaccines target the cholera bacteria or both the bacteria and the toxin.
David Pascual, an expert in infectious diseases and immunology at the University of Florida, thinks that the MucoRice vaccine has huge promise. "I truly believe that the development of a food-based vaccine can be effective. CTB has a natural affinity for sampling cells in the gut to adhere, be processed, and then stimulate our immune system, he says. "In addition to vaccinating the gut, MucoRice has the potential to touch other mucosal surfaces in the mouth, which can help generate an immune response locally in the mouth and distally in the gut."
Cost Effectiveness
Kiyono says the MucoRice vaccine is much cheaper to produce than a traditional vaccine. Current vaccines need expensive bioreactors to grow cell cultures under very controlled, sterile conditions. This makes them expensive to manufacture, as different types of cell cultures need to be grown in separate buildings to avoid any chance of contamination. MucoRice doesn't require such an expensive manufacturing process because the rice plants themselves act as bioreactors.
The MucoRice vaccine also doesn't require the high cost of cold storage. It can be stored at room temperature for up to three years unlike traditional vaccines. "Plant-based vaccine development platforms present an exciting tool to reduce vaccine manufacturing costs, expand vaccine shelf life, and remove refrigeration requirements, all of which are factors that can limit vaccine supply and accessibility," Breakwell says.
Kathleen Hefferon, a microbiologist at Cornell University agrees. "It is much less expensive than a traditional vaccine, by a long shot," she says. "The fact that it is made in rice means the vaccine can be stored for long periods on the shelf, without losing its activity."
A plant-based vaccine may even be able to address vaccine hesitancy, which has become a growing problem in recent years. Hefferon suggests that "using well-known food plants may serve to reduce the anxiety of some vaccine hesitant people."
Challenges of Plant Vaccines
Despite their advantages, no plant-based vaccines have been commercialized for human use. There are a number of reasons for this, ranging from the potential for too much variation in plants to the lack of facilities large enough to grow crops that comply with good manufacturing practices. Several plant vaccines for diseases like HIV and COVID-19 are in development, but they're still in early stages.
In developing the MucoRice vaccine, scientists at the University of Tokyo have tried to overcome some of the problems with plant vaccines. They've created a closed facility where they can grow rice plants directly in nutrient-rich water rather than soil. This ensures they can grow crops all year round in a space that satisfies regulations. There's also less chance for variation since the environment is tightly controlled.
Clinical Trials and Beyond
After successfully growing rice plants containing the vaccine, the team carried out their first clinical trial. It was completed early this year. Thirty participants received a placebo and 30 received the vaccine. They were all Japanese men between the ages of 20 and 40 years old. 60 percent produced antibodies against the cholera toxin with no side effects. It was a promising result. However, there are still some issues Kiyono's team need to address.
The vaccine may not provide enough protection on its own. The antigen in any vaccine is the substance it contains to induce an immune response. For the MucoRice vaccine, the antigen is not the cholera bacteria itself but the cholera toxin the bacteria produces.
"The development of the antigen in rice is innovative," says David Sack, a professor at John Hopkins University and expert in cholera vaccine development. "But antibodies against only the toxin have not been very protective. The major protective antigen is thought to be the LPS." LPS, or lipopolysaccharide, is a component of the outer wall of the cholera bacteria that plays an important role in eliciting an immune response.
The Japanese team is considering getting the rice to also express the O antigen, a core part of the LPS. Further investigation and clinical trials will look into improving the vaccine's efficacy.
Beyond cholera, Kiyono hopes that the vaccine platform could one day be used to make cost-effective vaccines for other pathogens, such as norovirus or coronavirus.
"We believe the MucoRice system may become a new generation of vaccine production, storage, and delivery system."
By mid-March, Alpha Lee was growing restless. A pioneer of AI-driven drug discovery, Lee leads a team of researchers at the University of Cambridge, but his lab had been closed amidst the government-initiated lockdowns spreading inexorably across Europe.
If the Moonshot proves successful, they hope it could serve as a future benchmark for finding new medicines for chronic diseases.
Having spoken to his collaborators across the globe – many of whom were seeing their own experiments and research projects postponed indefinitely due to the pandemic – he noticed a similar sense of frustration and helplessness in the face of COVID-19.
While there was talk of finding a novel treatment for the virus, Lee was well aware the process was likely to be long and laborious. Traditional methods of drug discovery risked suffering the same fate as the efforts to find a cure for SARS in the early 2000, which took years and were ultimately abandoned long before a drug ever reached the market.
To avoid such an outcome, Lee was convinced that global collaboration was required. Together with a collection of scientists in the UK, US and Israel, he launched the 'COVID Moonshot' – a project which encouraged chemists worldwide to share their ideas for potential drug designs. If the Moonshot proves successful, they hope it could serve as a future benchmark for finding new medicines for chronic diseases.
Solving a Complex Jigsaw
In February, ShanghaiTech University published the first detailed snapshots of the SARS-CoV-2 coronavirus's proteins using a technique called X-ray crystallography. In particular, they revealed a high-resolution profile of the virus's main protease – the part of its structure that enables it to replicate inside a host – and the main drug target. The images were tantalizing.
"We could see all the tiny pieces sitting in the structure like pieces of a jigsaw," said Lee. "All we needed was for someone to come up with the best idea of joining these pieces together with a drug. Then you'd be left with a strong molecule which sits in the protease, and stops it from working, killing the virus in the process."
Normally, ideas for how best to design such a drug would be kept as carefully guarded secrets within individual labs and companies due to their potential value. But as a result, the steady process of trial and error to reach an optimum design can take years to come to fruition.
However, given the scale of the global emergency, Lee felt that the scientific community would be open to collective brainstorming on a mass scale. "Big Pharma usually wouldn't necessarily do this, but time is of the essence here," he said. "It was a case of, 'Let's just rethink every drug discovery stage to see -- ok, how can we go as fast as we can?'"
On March 13, he launched the COVID moonshot, calling for chemists around the globe to come up with the most creative ideas they could think of, on their laptops at home. No design was too weird or wacky to be considered, and crucially nothing would be patented. The entire project would be done on a not-for-profit basis, meaning that any drug that makes it to market will have been created simply for the good of humanity.
It caught fire: Within just two weeks, more than 2,300 potential drug designs had been submitted. By the middle of July, over 10,000 had been received from scientists around the globe.
The Road Toward Clinical Trials
With so many designs to choose from, the team has been attempting to whittle them down to a shortlist of the most promising. Computational drug discovery experts at Diamond and the Weizmann Institute of Science in Rehovot, Israel, have enabled the Moonshot team to develop algorithms for predicting how quick and easy each design would be to make, and to predict how well each proposed drug might bind to the virus in real life.
The latter is an approach known as computational covalent docking and has previously been used in cancer research. "This was becoming more popular even before COVID-19, with several covalent drugs approved by the FDA in recent years," said Nir London, professor of organic chemistry at the Weizmann Institute, and one of the Moonshot team members. "However, all of these were for oncology. A covalent drug against SARS-CoV-2 will certainly highlight covalent drug-discovery as a viable option."
Through this approach, the team have selected 850 compounds to date, which they have manufactured and tested in various preclinical trials already. Fifty of these compounds - which appear to be especially promising when it comes to killing the virus in a test tube – are now being optimized further.
Lee is hoping that at least one of these potential drugs will be shown to be effective in curing animals of COVID-19 within the next six months, a step that would allow the Moonshot team to reach out to potential pharmaceutical partners to test their compounds in humans.
Future Implications
If the project does succeed, some believe it could open the door to scientific crowdsourcing as a future means of generating novel medicine ideas for other diseases. Frank von Delft, professor of protein science and structural biology at the University of Oxford's Nuffield Department of Medicine, described it as a new form of 'citizen science.'
"There's a vast resource of expertise and imagination that is simply dying to be tapped into," he said.
Others are slightly more skeptical, pointing out that the uniqueness of the current crisis has meant that many scientists were willing to contribute ideas without expecting any future compensation in return. This meant that it was easy to circumvent the traditional hurdles that prevent large-scale global collaborations from happening – namely how to decide who will profit from the final product and who will hold the intellectual property (IP) rights.
"I think it is too early to judge if this is a viable model for future drug discovery," says London. "I am not sure that without the existential threat we would have seen so many contributions, and so many people and institutions willing to waive compensation and future royalties. Many scientists found themselves at home, frustrated that they don't have a way to contribute to the fight against COVID-19, and this project gave them an opportunity. Plus many can get behind the fact that this project has no associated IP and no one will get rich off of this effort. This breaks down a lot of the typical barriers and red-tape for wider collaboration."
"If a drug would sprout from one of these crowdsourced ideas, it would serve as a very powerful argument to consider this mode of drug discovery further in the future."
However the Moonshot team believes that if they can succeed, it will at the very least send a strong statement to policy makers and the scientific community that greater efforts should be made to make such large-scale collaborations more feasible.
"All across the scientific world, we've seen unprecedented adoption of open-science, collaboration and collegiality during this crisis, perhaps recognizing that only a coordinated global effort could address this global challenge," says London. "If a drug would sprout from one of these crowdsourced ideas, it would serve as a very powerful argument to consider this mode of drug discovery further in the future."
[An earlier version of this article was published on June 8th, 2020 as part of a standalone magazine called GOOD10: The Pandemic Issue. Produced as a partnership among LeapsMag, The Aspen Institute, and GOOD, the magazine is available for free online.]
World’s First “Augmented Reality” Contact Lens Aims to Revolutionize Much More Than Medicine
Imagine a world without screens. Instead of endlessly staring at your computer or craning your neck down to scroll through social media feeds and emails, information simply appears in front of your eyes when you need it and disappears when you don't.
"The vision is super clear...I was reading the poem with my eyes closed."
No more rude interruptions during dinner, no more bumping into people on the street while trying to follow GPS directions — just the information you want, when you need it, projected directly onto your visual field.
While this screenless future sounds like science fiction, it may soon be a reality thanks to the new Silicon Valley startup Mojo Vision, creator of the world's first smart contact lens. With a 14,000 pixel-per-inch display with eye-tracking, image stabilization, and a custom wireless radio, the Mojo smart lens bills itself the "smallest and densest dynamic display ever made." Unlike current augmented reality wearables such as Google Glass or ThirdEye, which project images onto a glass screen, the Mojo smart lens can project images directly onto the retina.
A current prototype displayed at the Consumer Electronics Show earlier this year in Las Vegas includes a tiny screen positioned right above the most sensitive area of the pupil. "[The Mojo lens] is a contact lens that essentially has wireless power and data transmission for a small micro LED projector that is placed over the center of the eye," explains David Hobbs, Director of Product Management at Mojo Vision. "[It] displays critical heads-up information when you need it and fades into the background when you're ready to continue on with your day."
Eventually, Mojo Visions' technology could replace our beloved smart devices but the first generation of the Mojo smart lens will be used to help the 2.2 billion people globally who suffer from vision impairment.
"If you think of the eye as a camera [for the visually impaired], the sensors are not working properly," explains Dr. Ashley Tuan, Vice President of Medical Devices at Mojo Vision and fellow of the American Academy of Optometry. "For this population, our lens can process the image so the contrast can be enhanced, we can make the image larger, magnify it so that low-vision people can see it or we can make it smaller so they can check their environment." In January of this year, the FDA granted Breakthrough Device Designation to Mojo, allowing them to have early and frequent discussions with the FDA about technical, safety and efficacy topics before clinical trials can be done and certification granted.
For now, Dr. Tuan is one of the few people who has actually worn the Mojo lens. "I put the contact lens on my eye. It was very comfortable like any contact lenses I've worn before," she describes. "The vision is super clear and then when I put on the accessories, suddenly I see Yoda in front of me and I see my vital signs. And then I have my colleague that prepared a beautiful poem that I loved when I was young [and] I was reading the poem with my eyes closed."
At the moment, there are several electronic glasses on the market like Acesight and Nueyes Pro that provide similar solutions for those suffering from visual impairment, but they are large, cumbersome, and highly visible. Mojo lens would be a discreet, more comfortable alternative that offers users more freedom of movement and independence.
"In the case of augmented-reality contact lenses, there could be an opportunity to improve the lives of people with low vision," says Dr. Thomas Steinemann, spokesperson for the American Academy of Ophthalmology and professor of ophthalmology at MetroHealth Medical Center in Cleveland. "There are existing tools for people currently living with low vision—such as digital apps, magnifiers, etc.— but something wearable could provide more flexibility and significantly more aid in day-to-day tasks."
As one of the first examples of "invisible computing," the potential applications of Mojo lens in the medical field are endless.
According to Dr. Tuan, the visually impaired often suffer from depression due to their lack of mobility and 70 percent of them are underemployed. "We hope that they can use this device to gain their mobility so they can get that social aspect back in their lives and then, eventually, employment," she explains. "That is our first and most important goal."
But helping those with low visual capabilities is only Mojo lens' first possible medical application; augmented reality is already being used in medicine and is poised to revolutionize the field in the coming decades. For example, Accuvein, a device that uses lasers to provide real-time images of veins, is widely used by nurses and doctors to help with the insertion of needles for IVs and blood tests.
According to the National Center for Biotechnology Information, augmentation of reality has been used in surgery for many years with surgeons using devices such as Google Glass to overlay critical information about their patients into their visual field. Using software like the Holographic Navigation Platform by Scopsis, surgeons can see a mixed-reality overlay that can "show you complicated tumor boundaries, assist with implant placements and guide you along anatomical pathways," its developers say.
However, according to Dr. Tuan, augmented reality headsets have drawbacks in the surgical setting. "The advantage of [Mojo lens] is you don't need to worry about sweating or that the headset or glasses will slide down to your nose," she explains "Also, our lens is designed so that it will understand your intent, so when you don't want the image overlay it will disappear, it will not block your visual field, and when you need it, it will come back at the right time."
As one of the first examples of "invisible computing," the potential applications of Mojo lens in the medical field are endless. Possibilities include live translation of sign language for deaf people; helping those with autism to read emotions; and improving doctors' bedside manner by allowing them to fully engage with patients without relying on a computer.
"[By] monitoring those blood vessels we can [track] chronic disease progression: high blood pressure, diabetes, and Alzheimer's."
Furthermore, the lens could be used to monitor health issues. "We have image sensors in the lens right now that point to the world but we can have a camera pointing inside of your eye to your retina," says Dr. Tuan, "[By] monitoring those blood vessels we can [track] chronic disease progression: high blood pressure, diabetes, and Alzheimer's."
For the moment, the future medical applications of the Mojo lens are still theoretical, but the team is confident they can eventually become a reality after going through the proper regulatory review. The company is still in the process of design, prototype and testing of the lens, so they don't know exactly when it will be available for use, but they anticipate shipping the first available products in the next couple of years. Once it does go to market, it will be available by prescription only for those with visual impairments, but the team's goal is to bring it to broader consumer markets pending regulatory clearance.
"We see that right now there's a unique opportunity here for Mojo lens and invisible computing to help to shape what the next decade of technology development looks like," explains David Hobbs. "We can use [the Mojo lens] to better serve us as opposed to us serving technology better."