Science Interviews


Tue, 12th Jul 2016

Nanoparticles speed up vaccines

Dr. Omar F. Khan, Massachusetts Institute of Technology

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A breakthrough in vaccination technology, which could speed up the productionSyringe of vaccines for outbreaks like Ebola, Zika or the Flu, has been announced this week. Traditionally, vaccines are made by growing the infectious disease in culture and then deactivating and purifying it, and this takes time. But now Omar F. Khan has invented a nanoparticle that can deliver into the body small pieces of genetic information, in a form called RNA, that encode for parts of the disease-causing microbe. This enables the body to read those instructions and rapidly churn out both protective antibodies and infection-fighting white blood cells as he explained to Chris Smith.

Omar - We decided to turn the patients cells into the vaccine production factory. The way we do that is that we use nucleic acid or RNA ribose nucleic acid. That is genetic information. These are instruction sets that your cells can read and follow. So, we can tell the cells to produce the vaccine itself and in that way, we can train the immune system to immunise itself to fight off whatever disease we programme in.

Chris - What you're describing sounds very like what we call a DNA vaccine. The rationale there is you inject the genetic message corresponding to the thing that you want the immune system to make and learn to recognise and cells decode the DNA, and make that thing. But you're not using DNA. You're using its relative RNA which is, its like DNA but single stranded. Its the intermediate that the cells use when they turn DNA into a recipe that they're going to make. Why have you gone down that route of using RNA?

Omar - DNA had some inherent difficulties to it. The first one is that when you try to deliver DNA instruction sets, you need to get it inside the cell nucleus. Thats where you can activate and use and read the DNA instruction set. The other problem is that DNA is inherently dangerous. There is a chance that the DNA that you put inside a body can actually integrate into your normal DNA and these kind of random integrations can cause cancer.

Chris - And RNA can't do that.

Omar - RNA will never do that so its so much safer. The way this is done is first of all, my colleague can make these instruction sets that we can programme for any disease wed like. The novel bit of this technology is actually the nanotechnology delivery system. So what I've done is that I've made a special molecule. Its a nano material. This nano material is able to take those instruction sets and package them into nanoparticles. Those can just be injected into the muscle cells of the patient and in doing so, were able to achieve complete protective immunity for whatever disease we programme in.

Chris - Can you package more than one instruction set? So, if I wanted to do multiple vaccinations against multiple things at once, could I make a nanoparticle thats got in it these RNA instructions for a range of different entities so I just do one injection once?

Omar - Absolutely. In this nano material, I have designed in an enormous payload capacity which means I can put in multiple instruction sets, each encoding a unique disease if wed like or multiple targets for a single disease. So, multiple instruction sets can easily fit into this particular nano material.

Chris - What's the evidence though that this works? Does it really work if you give this to an animal?

Omar - Actually, yes. It works extremely well. So using the system, weve made vaccines against a wide variety of diseases including Ebola virus and H1N1 influenza, and toxoplasma gondii which is a microorganism parasite. So what weve done is weve actually vaccinated healthy animals with these nanoparticle vaccines. Then we gave them lethal exposures to all of these pathogens. And all of these animals have survived with a single injection. So that's tremendous results. First of all, single injection means you never have to go back to the hospital for second booster shots. Some vaccines need that. The fact that all these animals survived and are healthy despite being exposed to lethal exposures to deadly pathogens, that is proof positive that this works.

Chris - There's no danger that the nanoparticles will trigger an immune response in the animal against the particle so that the vaccine might work once but if you came back and tried to do it again, the immune system would gobble it up and destroy it before it had the chance to drive any immunity.

Omar - No. We dont have a problem with that because of two major points. First of all is that the system is so efficient that we need so little to vaccinate a patient that that should not elicit an immune response. Its also designed to actually be very tolerable to the body.



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