So, in order to keep the ball rolling, I thought I'd post a bit of science communication I wrote for my entry in last year's Max Perutz writing competition.
I was going to write an entry for the recent Euro-PMC competition, but I only got as far as deciding on the theme of the pun for my title (I was thinking something cheesy like 'Genius, or geneious?').
Anyway, here's the article as I wrote it last May (I didn't win).
Unravelling
the secrets of our immune system
Sometimes we only
realise how important something is when it goes wrong. In the case of
adaptive immunity, things going wrong can be fatal.
Adaptive immunity is
one of the systems we have evolved to keep infectious germs at bay.
It is our intelligent protection system, a biological firewall, where
white blood cells patrol our bodies, keeping us safe from disease.
Not only does it stop intruders in their tracks, it remembers the
threats it's seen before, so it can defend against them faster the
next time they attack.
There are two medical
conditions in humans that reveal to us how important it is to have a
working adaptive immune system. The first occurs when some children
are born without working copies of genes that encode important immune
molecules. This means they don't make some of the proteins that are
required for adaptive immunity to develop.
Alternatively, people
can lose their resistance to microbes later in life. This can happen
when untreated HIV positive individuals develop AIDS, or in
transplant patients who have taken suppressive drugs to prevent organ
rejection.
People without a
functioning adaptive immune system are compromised, exposed. They are
at risk from any stray infection, vulnerable to all manner of
viruses, bacteria and fungi. A simple bug that might not even give
you a temperature could spell death to them.
This makes it important
for us to know how adaptive immunity works. This is what I do in my
research; I look at a particular aspect of this system, to try and
understand what a healthy adaptive immune system 'looks' like, and
how it goes wrong in disease.
In order to explain my
work, you have to know a little bit about how our bodies generate
this powerful immunity.
Cells don't have eyes
or ears, so they have to use receptor molecules on their surface to
detect what's going on around them in their environment. These
receptors are proteins, the blueprints for which are encoded in the
genes in our DNA.
This means white blood
cells could have a receptor that recognises a certain bit of a
bacteria say, or the fragment of the outside of a virus. If the
receptor finds and binds its target, then that cell can tell that the
body is infected with a particular parasite.
The problem lies in
that there are far more bugs and germs out there that could
potentially infect us then there are genes in our genome. How can we
have evolved ways to detect and protect against such a barrage of
disease with so few genes?
Maturing adaptive
immune cells overcome our finite genomes by shuffling pieces of it
around, making unique receptor genes out of genetic building blocks
that all our cells contain. These cells, called T cells and B cells,
physically loop the DNA over itself, and then cut out the chunks in
between.
This means different
sections can be moved next to each other, recombining to create new
genes. Incidentally, this extraordinary feature makes them some of
the only cells in the body that don't share the same genome as all
the other cells.
Each developing cell
shuffles their DNA around independently, stitching different gene
segments together in order to produce its own distinctive receptor.
As there are many segments to choose from, the number of different
combinations is huge.
Moreover, the DNA
sequence at the join sites can be randomly altered, meaning the
eventual number of possible different receptor genes is truly
phenomenal. The fact that we have millions of white blood cells
inside us, each bearing one of the trillions of different potential
receptors, has historically kept researchers from measuring this
diversity.
My project is to use
DNA sequencing technology – developed during the Human Genome
Project – to read as many of these uniquely generated adaptive
immune genes as we can. By doing this we can characterise a person's
immune repertoire, seeing how prepared their body is to fight off
infection, and perhaps even see what they’ve been infected by in
the past.
The hope is that we can
use this technology to understand what it is that makes a healthy
human immune system. Once we know this, we can compare this to the
compromised or failing immune systems that we see in infection,
cancer and autoimmunity, and maybe get an insight into how to treat
or avoid these conditions.
Science has brought a
lot of relief to those suffering from disease, and has prevented many
more from joining them. However, the challenges faced in curing our
ills can only be surmounted by learning as much as possible about the
way that our bodies work, as well as the diseases that threaten us.
Unravelling the secrets of our immune systems is another step towards
that goal.
