As you walk into a small room in Kenya, you see a child, huddled in the corner of his bed. He’s shaking uncontrollably, and his skin is covered with a sheen of sweat. While you pause hesitantly beside the door, his mother carries in a pile of blankets and heaps them onto the child. The boy continues to shiver.
Later, you find out that this unfortunate child has been infected with malaria, the number one cause of childhood death in Kenya (Nesoba, 2010). Around the world, the number of annual deaths due to malaria was about 655,000 in 2011, according to the World Health Organization (Berkowitz, 2012). Malaria is a mosquito-borne disease that takes on many different forms through its life cycle both inside the mosquito as well as inside the human body. Because of all this shape shifting, researchers have found extremely difficulty in developing a working vaccine.
The Massachusetts Herd: Vaccine-Producing Goats
For years, scientists from many universities and companies around the globe have been trying different ways to produce an effective vaccine; most methods are geared towards cell cultures in labs, but there is one especially creative method that stands out from the others.
Scientists have targeted MSPs, or malarial merozoite surface proteins, as a viable vaccine candidate. MSPs have been tested on humans in Papua New Guinea, and are successful in raising an immune response to malaria (Nicholls, 2004). Usually, MSPs are insoluble, and therefore hard to purify. However, realizing that the success of MSPs as a vaccine could lead to huge demand, about ten years ago, researchers at GTC Biotherapeutics (now called rEVO) turned to goats to mass produce the vaccine. A herd of goats in Massachusetts was genetically engineered to produce MSPs in their milk. For a reason not yet understood, MSPs from goat milk are not as difficult to purify. A herd of fifty goats could produce about 5 kg of protein, or MSPs, every year to be used in vaccines (Nicholls, 2004).
The Texas Herd: Drinkable Vaccine?
Last year, another herd of genetically engineered goats was raised in Houston, Texas by researchers from Texas A&M University. This time, the researchers’ objective was to provide an economic form of drinkable vaccine for those in third world countries. Their ultimate goal was to produce a herd of goats that would produce a drinkable form of malaria vaccine in their milk that didn’t have to be further processed with sophisticated equipment to be effective. The researchers have already successfully bred three goats that can produce vaccine in their milk. However, the product isn’t at its finest yet—the vaccine in these goats’ milk still has to be separated, purified, and injected in order to be useful. Researchers say it could take up to another 10 years to eliminate these extra steps (Berkowitz, 2012).
GTC Biotherapeutics was the company that first produced the transgenic malaria vaccines used in both the earlier and more recent projects. Harry Meade, Senior Vice President of Research and Development, said of the Massachusetts project, “I don’t think anybody has any other system that they could contemplate making these kinds of levels as cheap as what you can in milk” (Berkowitz, 2012). William Gavin, who is the GTC Senior Vice President of Operations, said that the vaccine produced was tested on mice, and it worked. For the more recent project in Houston, A&M had initially received embryos from GTC to implant in surrogate goat mothers, and these embryos had the malaria antigen. Three goats, No. 21 (female), and No. 17 and No. 19 (both males) were born within a day of each other, and all carried the malaria antigen. When No. 21 turned 9 months old, she was mated with No. 17 (Berkowitz, 2012). They hope to produce a herd of these transgenic goats.
Someday, the researchers hope to have a whole herd of goats that will produce a drinkable vaccine in their milk. The three goats bred for the experiment were chosen for their small size and hardiness. According to Mark Westhusin, a Texas A&M professor and a leader of the project, “They are easy to keep…They are just great animals in terms of what they offer to impoverished countries” (Berkowitz, 2012). These characteristics make them ideal for shipping to other countries, and make them easy to care for.
Other Uses for Transgenic Goats
The transgenic goat idea could also be used to cure other diseases—for instance, researchers are also currently using transgenic goats to produce more lysozymes (which protect against diarrheal diseases) in their milk (Schiller). Vaccines for diseases like chickenpox or HIV may even be produced in goat milk one day, making these treatments more accessible for people in developing countries. Recently, transgenic goats have also been used for purposes other than curing diseases—scientists have created goats that produce spider silk in their milk. The silk can be used for making artificial tendons or ligaments, true; but it can also be used for bulletproof vests and car airbags.
So, maybe in ten years, in the same village in Kenya that you walked into before, people will drink milk from goats around their community and will automatically be vaccinated against malaria. People will no longer have to worry as much about their children dying young from this disease, and they can instead focus on improving their lives in other ways. Milk, which has always been associated with healing, nurturing, and recovery, now has the potential to vaccinate against one of the most deadly diseases in the world—malaria.
- Malaria is caused by an organism that shifts its shape a lot, so a vaccine is very hard to develop.
- About 10 years ago, malarial merozoite surface proteins, or MSPs, were identified as a viable vaccine for malaria.
- To mass-produce MSPs, scientists at GTC Biotherapeutics genetically engineered a herd of goats to produce MSPs in their milk.
- Last year, more goats that produced milk with vaccine were bred in Houston—their purpose is to produce an economic drinkable form of malaria vaccine for third world countries.
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