ZMapp: A Case for GMOs

A lot of people are against GMOs (genetically modified organisms).  There is some hysteria over them and also well thought-out arguments about why they could be dangerous.  There is abundant misinformation spread across the internet.  There are also people and companies that abuse GMOs. But GMOs can be really useful.  They can increase crop yield and resistance to pests, they can be used to make medicine and are widely used in labs for studying, well, virtually everything.  Eventually I want to tackle all of these complicated issues.

But today, I want to talk about a GMO that could save lives: ZMapp.

What is a Genetically Modified Organism (GMO)?

A GMO is any organism whose genetic material has been altered specifically through engineering.  It includes adding genes, deleting genes or mutating genes.  Although you mostly read about GMO food these days, GMO bacteria, yeast, fish, viruses and plants are all used.

Some argue that GMO production is an extension of selective breeding – the process in which animals and plants are purposefully bred together to create an offspring with a desired trait.  Probably the most extensive of this is our creation of some 300 dog breeds from a single ancestral gray wolf.

The difference between selective breeding and GMO production is that the genetic material of the organism is directly manipulated, called genetic engineering.  And many times foreign genetic material is added to an organism to give it new traits.

What is ZMapp?

ZMapp is the experimental drug that was given to the two Samaritan’s Purse workers that were infected with Ebola during the current Ebola outbreak in West Africa.  The workers were given ZMapp, an investigational drug that hasn’t been approved for use in humans.  They were then transferred to the US where they received better care than those being treated in Africa.  Despite the 71% mortality rate of the current outbreak, both workers survived.

We don’t know whether ZMapp saved them.  There are too many variables here to determine that.  That is why clinical trials need to be done.  I hope it is a viable treatment for Ebola, but we are going to have to wait a while before we know.

The reason why this drug is so interesting to me, is they way it is made.

First a Little Genetic Engineering

The ZMapp drug is an antibody – those infection fighting molecules that parole your bloodstream seeking and destroying pathogen invaders. If you have antibodies in your bloodstream that recognize a pathogen, the chances that you will be able to fight the pathogen off are greatly increased.

The ZMapp antibodies were made by injecting mice with pieces of the Ebola virus (kind of like vaccination).  Once the mice were making antibodies to Ebola, the cells that produce those antibodies were grown in the lab.  The scientists picked the cells that made the best antibody and then plucked out the piece of mouse DNA (or gene) that codes for making the antibody.  To make the antibody more effective in humans, parts of the mouse DNA were replaced with human DNA making a hybrid mouse-human antibody (called humanized antibodies).

GMOs at Their Finest

The next step was to find a way to produce and isolate large amounts of the antibody.  And the makers of ZMapp turned to tobacco plants.

But they needed a way to get the DNA for the antibody into the DNA of the plant.  So, they turned to viruses (those buggers are great, aren’t they?).  A tobacco plant virus (yes, plants have viruses too!) was engineered to carry the mouse-human antibody and used to infect tobacco plants.  The virus delivered the DNA into the plants where it became accepted as part of their own DNA.

The plants were then grown en masse and the antibodies were extracted and purified from the plants.

To Sum It Up

Ebola virus parts were injected into mice to make antibodies.  The gene that made the antibodies was isolated and engineered to be part human.  The mouse-human gene was used to make a GMO virus that could infect tobacco plants and pass on the gene, creating another GMO.  The tobacco plants were used to make the antibody that was then isolated and injected into Ebola-infected humans.  All with the hope that this genetically modified antibody, that required 3 organisms to make, would function in humans to fight the disease.

The people that receive ZMapp won’t start craving cheese and squeaking, they won’t have a constant nicotine high and they aren’t infected with tobacco viruses.  But due to genetic engineering and two GMOs, they might have a better chance of living.

Photo courtesy of Karoly Lorentey.