Viral vectors in cancer immunotherapy

Written by Tory Maxted, Senior Clinical Data Manager 2

We are currently living in a world where medicine has an answer for just about everything, these answers have meant that we live far beyond what might be our ‘natural’ life expectancy. As anyone who has watched a bit of sci-fi will know, races or beings that replicate by cloning often die out, because making copies of copies of copies leads to degradation of information. The cells in our bodies replicate by copying - division, we make new from old and do pretty well at it for a long time (bar any bad genetics getting in the way). However, we push our bodies to keep this up for 80 odd years, and understandably our bodies accumulate errors in the code and sometimes these changes can lead to cancer. The body’s ability to function hangs on the interactions of thousands of proteins you’ve never even heard of. Producing a little too much of one can send a cell down the road to uncontrolled division where it sets up shop in an organ until its ready to spread.

One of the most common types of treatment given to cancer patients is cytotoxic therapy. These ‘cell killing’ therapies are a balancing act between the awful side effects and eliminating the cancer; if the person survives they are often left with the lingering side effects and live constantly with re-occurrence looming over them.

At last, science has something else in mind. A recent paper published in nature communications here, suggests the use of viral vectors to help the immune system fight the battle against cancer for us.

Unfortunately the immune system has a tough time recognising cancer on its own. The immune system is carefully evolved NOT to recognise its own body cells, and when it does disaster ensues (autoimmune diseases). Scientists intend to give the immune system a little help. The nature paper reports use of a live attenuated Lymphocytic Choriomeningitis Virus (LCMV) vector to induce cytotoxic T cells that are primed for recognising tumor cells. Once the T-cells are able to recognise the tumor cells, it’s a level playing field, making tumors more responsive to immunomodulatory therapies. Even better than this, because the immune system has memory, risk of recurrence may also be less, much like how modern vaccines prevent infections. This new work may pave the way for novel cancer treatments of the future, giving the immune system the ability to spot its own mistakes and get to work on fighting cancer.

So far this particular immunotherapy has only been tested in mice. As with all novel treatments it will have to undergo many more years of testing before it can be given to human subjects, but this kind of research is a really exciting prospect for the future treatment of cancer – harnessing a natural resource like viruses and adapting them to solve a problem.