Genetically engineered cattle + human DNA = Ebola cure?

DairyCow_inField_blogA herd of 50 cloned, genetically engineered cattle on a farm just outside Sioux Falls, South Dakota, may hold the key to producing a vaccine against the Ebola virus, which has infected more than 21,000 people in West Africa, killing more than 8,500 of them and causing hysteria worldwide.

According to a recent article, this group of cattle has been genetically engineered with human DNA so that their bodies no longer produce cattle antibodies but rather, human antibodies. Scientists have then vaccinated these animals against various deadly diseases such as Ebola. Their bodies produce antibodies in response to these vaccines, and the hope is these antibodies can then be used to treat people with the disease.

“These animals produce very high levels of human antibody,” Eddie Sullivan, president and CEO of SAb Biotherapeutics, the company that developed the cattle, said in the article.

This approach is similar to the idea behind transfusing plasma from Ebola survivors into patients. While it is still unclear if this treatment actually works, experiments are under way in Liberia and at Emory University Hospital in Atlanta to see if the blood of Ebola survivors can help kick-start the immune response in a patient with the disease.

This immune response is critical because this is when the body identifies the invading germs and produces antibodies and immune cells to kill them. As stated in the article, the human immune system is especially advanced and can produce both antibodies and immune cells that over the course of time will remember previous infections and continue fighting them in order to prevent a second infection by the same germ.

“From these animals, we can collect 30 to 60 liters of plasma each month,” Sullivan told NBC News. “That translates into something between 500 to 1,000 human doses per month per animal,” something he said could make the project larger-scale.

This same approach was researched and used against hantavirus, a rare killer virus that causes regular outbreaks, including one that killed three campers at Yosemite National Park in 2012. However, experiments using an Ebola vaccine were fast-tracked when the epidemic broke out in Liberia, Sierra Leone and Guinea last year.

After the cattle are vaccinated against Ebola, using what’s called a DNA vaccine, the plasma is removed and the antibodies are taken out and shipped to the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID) labs in Maryland for testing. According to the article, there a team first infect mice with Ebola virus, then gives them a dose of the antibodies.

“The first mouse studies have shown we can protect mice one day after they have been infected but not two days after they have been infected with a single dose,” Connie Schmaljohn, a senior research scientist at USAMRIID told NBC News. Now, the team is giving the mice a dose a day to see if that helps. If so, the next step will be to test the approach in monkeys and if that works, it could be quickly deployed for testing in people, Schmaljohn said.

As of now, Schmaljohn stresses that many uncertainties remain. However, since only about 10% of the cattle embryos survive as calves, it is clear that this group of cattle is very unique as well as very expensive. But if the approach works, their human immune systems mean they could be a gold mine for Ebola and other treatments including various strains of influenza and the Middle East respiratory syndrome (MERS), which has infected 948 people and killed at least 349.

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