Plague Prevention

It’s been many years since the last plague pandemic and occurrences in developed countries are rare, but there are concerns that the disease could be exploited for bioterrorism. Plague is caused by the Yersinia pestis bacterium and though treatments do exist, few countries have a vaccine available.

One company working to combat the plague is Prokarium, a UK-based company that focuses on developing oral vaccines using synthetic biology. Recently, the company was awarded funding from the UK government to help develop new vaccines targeting Zika, bacterial diarrhoea and plague – with £1 million being targeted directly at the latter. We spoke with Ted Fjallman, CEO at Prokarium, to find out more.

What inspired the company to pursue plague prevention?

The work of Rocky Craneburgh – our Chief Scientific Officer – on plague predates the company, so you could say we have a long history and interest in this field. Plague still kills people every year, mostly in developing countries, but it could also pose a grave danger if it were cultured and aerosolized by terrorists. Prokarium’s Chairman, Steve Chatfield, is a vaccine preparedness and defence specialist, who advises governments and NATO on how to prepare for bioterror attacks, so we have a lot of expertise and technology to help with this area. However, I think the need to create vaccines against deadly diseases for which there is currently no vaccine is our main motivation.

Has plague received much attention from the pharma industry?

Dangerous diseases with the potential to become serious epidemics are always of interest, but unfortunately in a boot-strapped biopharma industry, it sometimes takes an outbreak – such as that for Ebola and Zika – for governments and industry to really kick into action. However, we simply cannot wait for a well-orchestrated bioterror attack to happen.

Our funding comes from the UK’s Small Business Research Initiative scheme, which is run by Innovate UK. They are doing a good job of encouraging the UK vaccine industry to tackle more neglected diseases, while still leaving the intellectual property rights intact to allow businesses to exploit the technologies for many different applications. Often, innovation needs to occur in novel funding mechanisms as well as in science to deliver true breakthroughs.

How far have you got with your plague vaccine?

We have promising preclinical data showing that we can produce strong immune responses and protect mice against a plague challenge. We have also shown that our vaccines are stable at 40 °C for more than 12 weeks and can be stored in the fridge for more than three years.

You hope to develop an oral vaccine – how?

We have technology that allows the vaccine to survive the stomach. When in the small intestine, our engineered bacteria enter the gut line where they are engulfed by the body’s own immune cells. Then (and only then) the bacteria start producing the vaccine from within those immune cells. This is the exact place you want a vaccine to go to work – within the immune cells at a mucosal surface – because you want to reach the immune system quickly with little or no side effects. In addition, our method means that we can teach the ‘mucosal part’ of the immune system to act as a first line of defence in, for example, the gut lining, nose, or vaginal tract. This is something that injectable vaccines cannot do. We are also finding that it is much cheaper (around 70 percent) to manufacture our vaccine than it is to manufacture an injectable.