Immuno Oncology: If cancer was a pathogen, would a vaccine be able to destroy it?

Thanks to the great intuitions of brilliant scientists like Louis Pasteur, Edward Jenner, Robert Koch, Emil von Behring, Gaston Leon Ramon, Albert Sabin, Jonas Salk in the past century, the world has gotten to know the super power inside every individual: THE IMMUNE SYSTEM.

“Find a pathogen, isolate it, kill it and inject it in the host…… the rest is left to our immune system”.

Thanks to that concept, microorganisms like Yersinia pestis, Spanish flu and many others responsible of devastating society provoking millions of deaths were finally facing the end of their days thanks to a very simple, yet new concept developed by the greatest minds of the past century“ Vaccination”.

This was the beginning of what vaccines would have become: powerful striking weapons against microorganisms threatening our existence on this planet.

Lymphocytes as an Immuno-oncology defense

Most of us are luckily equipped with a plethora of fighters able to recognise, neutralize, seek and destroy a dangerous microbe when encountered in our life span. Those warriors are specifically called lymphocytes and mostly have the function of keeping us immune for the rest of our life from a pathogen, creating a memory able to recall the fighting activity if eventually the infection will reoccur.

The role of the Immune system in Immuno-oncology

When our immune system is exposed to pathogens artificially attenuated or inactive is still able to get trained for a hypothetical encounter of the real microbe. The so called process vaccination is able to trigger an immunity for life without undergoing the danger of the real disease.

Now, that is true for pathogens like bacteria and viruses and it has been validated on millions of people in the past century and it continues nowadays.

When it comes to other diseases, especially the ones where our immune system has been recognised to play an important role like in cancer, can we apply the same principle for pathogens which is an external thread (non-self) to an abnormal tissue growth of our same cells (self)?

In short…. Can we fight cancer through vaccination?

Recognizing cancer cells

The major challenge for this approach is to direct our immune system against cancer cells only and not towards the healthy tissues. For those purpose, the identification of specific signatures discriminating cancer cells from healthy cells is pivotal.

On top of that, waking up the immune system and keep it active toward a target of our interest is extremely difficult and the scientific community has been wondering how to get to that point.

Oncolytic viruses as an Immuno-onocology approach

Luckily in the last decade virology came in our help and together with bioengineering, provided a great tool which would serve our cause to fight cancer and wake up the immune system: Oncolytic viruses. Those viruses have been modified to gain the ability to infect, replicate and destroy only cancer cells leaving the healthy cells alive.

Unfortunately, our immune system senses the virus as an external thread and tries to destroy it as it would normally do against every pathogen.

Furthermore, the tumor structure is not homogenous and those oncolytic viruses are not able to equally propagate and elicit their infection to all the cancer cells.

Despite the few drawbacks just mentioned, the power of those little allies can still turn in our favour.

It is true that mostly the immune system starts an anti-viral response rather than an anti-cancer but on the other hand we can use the virus as an activator of the immune machinery and on top of that we can mock our immune system to attack what we decide to attack.

What if we dress our little virus as the tumor? Our immune system does not own a catalogue of the different viruses, it just knows that whatever looks like a virus needs to be destroyed…….. so from that our IDEA…… let´s mount specific tumor proteins on the virus surface…. So when the immune system will detect and acquire an immunity against the virus… it will direct that response against everything looking like the proteins present on the virus surface.

Those proteins will be the tumoral proteins and they will orchestrate the lymphocytes against the cancer chosen.

In that way we would be able to ignite the immune system with our virus serving as an activator (adjuvant) and to direct that response towards whatever looks like the proteins we are attaching on the virus surface.