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."
Will the Pandemic Propel STEM Experts to Political Power?
If your car won't run, you head to a mechanic. If your faucet leaks, you contact a plumber. But what do you do if your politics are broken? You call a… lawyer.
"Scientists have been more engaged with politics over the past three years amid a consistent sidelining of science and expertise, and now the pandemic has crystalized things even more."
That's been the American way since the beginning. Thousands of members of the House and Senate have been attorneys, along with nearly two dozen U.S. presidents from John Adams to Abraham Lincoln to Barack Obama. But a band of STEM professionals is changing the equation. They're hoping anger over the coronavirus pandemic will turn their expertise into a political superpower that propels more of them into office.
"This could be a turning point, part of an acceleration of something that's already happening," said Nancy Goroff, a New York chemistry professor who's running for a House seat in Long Island and will apparently be the first female scientist with a Ph.D. in Congress. "Scientists have been more engaged with politics over the past three years amid a consistent sidelining of science and expertise, and now the pandemic has crystalized things even more."
Professionals in the science, technology, engineering and medicine (STEM) fields don't have an easy task, however. To succeed, they must find ways to engage with voters instead of their usual target audiences — colleagues, patients and students. And they'll need to beat back a long-standing political tradition that has made federal and state politics a domain of attorneys and businesspeople, not nurses and biologists.
In the 2017-2018 Congress, more members of Congress said they'd worked as radio talk show hosts (seven) and as car dealership owners (six) than scientists (three — a physicist, a microbiologist, and a chemist), according to a 2018 report from the Congressional Research Service. There were more bankers (18) than physicians (14), more management consultants (18) than engineers (11), and more former judges (15) than dentists (4), nurses (2), veterinarians (3), pharmacists (1) and psychologists (3) combined.
In 2018, a "STEM wave" brought nine members with STEM backgrounds into office. But those with initials like PhD, MD and RN after their names are still far outnumbered by Esq. and MBA types.
Why the gap? Astrophysicist Rush Holt Jr., who served from 1999-2015 as a House representative from New Jersey, thinks he knows. "I have this very strong belief, based on 16 years in Congress and a long, intense public life, that the problem is not with science or the scientists," said. "It has to do with the fact that the public just doesn't pay attention to science. It never occurs to them that they have any role in the matter."
But Holt, former chief executive of the American Association for the Advancement of Science, believes change is on the way. "It's likely that the pandemic will affect people's attitudes," former congressman Holt said, "and lead them to think that they need more scientific thinking in policy-making and legislating." Holt's father was a U.S. senator from West Virginia, so he grew up with a political education. But how can scientists and medical professionals succeed if they have no background in the art of wooing voters?
That's where an organization called 314 Action comes in. Named after the first three digits of pi, 314 Action declares itself to be the "pro-science resistance" and says it's trained more than 1,400 scientists to run for public office.
In 2018, 9 out of 13 House and Senate candidates endorsed by the group won their races. In 2020, 314 Action is endorsing 12 candidates for the House (including an engineer), four for the Senate (including an astronaut) and one for governor (a mathematician in Kansas). It expects to spend $10 million-$20 million to support campaigns this year.
"Physicians, scientists and engineers are problem-solvers," said Shaughnessy Naughton, a Pennsylvania chemist who founded 314 Action after an unsuccessful bid for Congress. "They're willing to dive into issues, and their skills would benefit policy decisions that extend way beyond their scientific fields of expertise."
Like many political organizations, 314 Action focuses on teaching potential candidate how to make it in politics, aiming to help them drop habits that fail to bridge the gap between scientists and civilians. "Their first impulse is not to tell a story," public speaking coach Chris Jahnke told the public radio show "Marketplace" in 2018. "They would rather start with a stat." In a training session, Jahnke aimed to teach them to do both effectively.
"It just comes down to being able to speak about general principles in regular English, and to always have the science intertwined with basic human values," said Rep. Kim Schrier, a Washington state pediatrician who won election to Congress in 2018.
She believes her experience on the job has helped her make connections with voters. In a chat with parents about vaccines for their child, for example, she knows not to directly jump into an arcane discussion of case-control studies.
The best alternative, she said, is to "talk about how hard it is to be a parent making these decisions, feeling scared and worried. Then say that you've looked at the data and the research, and point out that pediatricians would never do anything to hurt children because we want to do everything that is good for them. When you speak heart to heart, it gets across the message and the credibility of medicine and science."
The pandemic "will hopefully awaken people and trigger a change that puts science, medicine and public health on a pedestal where science is revered and not dismissed as elitist."
Communication skills will be especially important if the pandemic spurs more Americans to focus on politics and the records of incumbents in regard to matters like public health and climate change. Thousands of candidates will have to address the nation's coronavirus response, and a survey commissioned by 314 Action suggests that voters may be receptive to those with STEM backgrounds. The poll, of 1,002 likely voters in early April 2020, found that 41%-46% of those surveyed said they'd be "much more favorable" toward candidates who were doctors, nurses, scientists and public health professionals. Those numbers were the highest in the survey compared to just 9% for lawyers.
The pandemic "will hopefully awaken people and trigger a change that puts science, medicine and public health on a pedestal where science is revered and not dismissed as elitist," Dr. Schrier said. "It will come from a recognition that what's going to get us out of this bind are scientists, vaccine development and the hard work of the people in public health on the ground."
[This article was originally 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.]
The coronavirus pandemic exposed significant weaknesses in the country's food supply chain. Grocery store meat counters were bare. Transportation interruptions influenced supply. Finding beef, poultry, and pork at the store has been, in some places, as challenging as finding toilet paper.
In traditional agriculture models, it takes at least three months to raise chicken, six to nine months for pigs, and 18 months for cattle.
It wasn't a lack of supply -- millions of animals were in the pipeline.
"There's certainly enough food out there, but it can't get anywhere because of the way our system is set up," said Amy Rowat, an associate professor of integrative biology and physiology at UCLA. "Having a more self-contained, self-sufficient way to produce meat could make the supply chain more robust."
Cultured meat could be one way of making the meat supply chain more resilient despite disruptions due to pandemics such as COVID-19. But is the country ready to embrace lab-grown food?
According to a Good Food Institute study, GenZ is almost twice as likely to embrace meat alternatives for reasons related to social and environmental awareness, even prior to the pandemic. That's because this group wants food choices that reflect their values around food justice, equity, and animal welfare.
Largely, the interest in protein alternatives has been plant-based foods. However, factors directly related to COVID-19 may accelerate consumer interest in the scaling up of cell-grown products, according to Liz Specht, the associate director of science and technology at The Good Food Institute. The latter is a nonprofit organization that supports scientists, investors, and entrepreneurs working to develop food alternatives to conventional animal products.
While lab-grown food isn't ready yet to definitively crisis-proof the food supply chain, experts say it offers promise.
Matching Supply and Demand
Companies developing cell-grown meat claim it can take as few as two months to develop a cell into an edible product, according to Anthony Chow, CFA at Agronomics Limited, an investment company focused on meat alternatives. Tissue is taken from an animal and placed in a culture that contains nutrients and proteins the cells need to grow and expand. He cites a Good Food Institute report that claims a 2.5-millimeter sample can grow three and a half tons of meat in 40 days, allowing for exponential growth when needed.
In traditional agriculture models, it takes at least three months to raise chicken, six to nine months for pigs, and 18 months for cattle. To keep enough maturing animals in the pipeline, farms must plan the number of animals to raise months -- even years -- in advance. Lab-grown meat advocates say that because cultured meat supplies can be flexible, it theoretically allows for scaling up or down in significantly less time.
"Supply and demand has drastically changed in some way around the world and cultivated meat processing would be able to adapt much quicker than conventional farming," Chow said.
Scaling Up
Lab-grown meat may provide an eventual solution, but not in the immediate future, said Paul Mozdziak, a professor of physiology at North Carolina State University who researches animal cell culture techniques, transgenic animal production, and muscle biology.
"The challenge is in culture media," he said. "It's going to take some innovation to get the cells to grow at quantities that are going to be similar to what you can get from an animal. These are questions that everybody in the space is working on."
Chow says some of the most advanced cultured meat companies, such as BlueNal, anticipate introducing products to the market midway through next year. However, he thinks COVID-19 has slowed the process. Once introduced, they will be at a premium price, most likely available at restaurants before they hit grocery store shelves.
"I think in five years' time it will be in a different place," he said. "I don't think that this will have relevance for this pandemic, but certainly beyond that."
"Plant-based meats may be perceived as 'alternatives' to meat, whereas lab-grown meat is producing the same meat, just in a much more efficient manner, without the environmental implications."
Of course, all the technological solutions in the world won't solve the problem unless people are open-minded about embracing them. At least for now, a lab-grown burger or bluefin tuna might still be too strange for many people, especially in the U.S.
For instance, a 2019 article published by "Frontiers in Sustainable Food Systems" reflects results from a study of 3,030 consumers showing that 29 percent of U.S. customers, 59 percent of Chinese consumers, and 56 percent of Indian consumers were either 'very' or 'extremely likely' to try cultivated meat.
"Lab-grown meat is genuine meat, at the cellular level, and therefore will match conventional meat with regard to its nutritional content and overall sensory experience. It could be argued that plant-based meat will never be able to achieve this," says Laura Turner, who works with Chow at Agronomics Limited. "Plant-based meats may be perceived as 'alternatives' to meat, whereas lab-grown meat is producing the same meat, just in a much more efficient manner, without the environmental implications."
A Solution Beyond This Pandemic
The coronavirus has done more than raise awareness of the fragility of food supply chains. It has also been a wakeup call for consumers and policy makers that it is time to radically rethink our meat, Specht says. Those factors have elevated the profile of lab-grown meat.
"I think the economy is getting a little bit more steam and if I was an investor, I would be getting excited about it," adds Mozdziak.
Beyond crises, Mozdziak explains that as affluence continues to increase globally, meat consumption increases exponentially. Yet farm animals can only grow so quickly and traditional farming won't be able to keep up.
"Even Tyson is saying that by 2050, there's not going to be enough capacity in the animal meat space to meet demand," he notes. "If we don't look at some innovative technologies, how are we going to overcome that?"