Antibodies are the warriors inside our body.
They are part of our immune system, recognising
and fighting against bad foreign invaders,
called antigens.
Antibodies can bind to a broad range of antigens,
and are produced by cells of the immune system,
known as B-cells.
To learn more about antibodies and antigens,
watch this video.
Antibodies can be used for medical and diagnostic
applications, in the form of monoclonal antibodies.
So, what are monoclonal antibodies?
The word monoclonal means a single clone.
Monoclonal antibodies are identical antibodies
produced in laboratories from a single clone
of immune cells.
The cloned immune cells are genetically completely
identical. And so the antibodies they produce
are also identical to one another. Which is
perfect - to work properly, we need large
numbers of identical antibodies.
Monoclonal antibodies have a high specificity,
which means they can recognize and bind to
a single antigen binding site. This means
they are targeted to a specific antigen, and
is a key trait that makes them useful in diagnosing
and treating diseases.
So how are they produced?
Well first off we need an immune system. Which
is why we use mice.
In a laboratory, a mouse is vaccinated with
the target antigen.
This stimulates the B-cells, found in the
spleen, to produce antibodies against the
target antigen.
The spleen of the mouse is then removed.
The B-cells in the spleen are isolated, and
fused with a tumour cell. We need to fuse
the antibody producing b cells with a tumour
cell, because the b-cells don’t have the
ability to divide. BUT tumours however do
divide easily.
This fusion cell is called a Hybridoma cell.
The hybridoma cells reproduce rapidly to make
cloned cells, which all make the same antibody.
These monoclonal antibodies are collected
and purified, ready for use. They match up
perfectly with the target antigens in the
body. And are made in huge quantities.
Monoclonal antibodies are potentially really
exciting, and can be used in a number of ways...
I bet you didn’t know antibodies were used
in pregnancy tests!!
Monoclonal antibodies on the pregnancy test
stick bind to the HCG hormone found in the
urine of pregnant women causing a colour change.
Monoclonal antibodies can target the antigens
on cancer cells and be used in a number of
ways...
Firstly, by combining them with an anti-cancer
drug which can then accurately locate and
target only the cancer cells or avoiding the
healthy cells.
Secondly for detection… they can carry special
markers which show doctors where the cancerous
cells are starting to build up.
Thirdly, they can be used to trigger the body’s
own immune system to recognise and kill the
cancer cells
They can also be used to identify other diseases,
and locate blood clots.
So those are a few uses… but are they all
good?
We’ve seen the positives, so what are some
criticisms? They are expensive and time consuming
to produce… they have more side effects
than expected; and they are too specific meaning
that whilst yes they can diagnose and attack
diseases, they only can attack one type each
time. A more diverse and adaptable solution
would be better.
The potential power of monoclonal antibodies
is clear. They are not yet as widely used
as everyone hoped when they were first developed,
but scientists are working hard to make them
better and safer for wider use. Their journey
is just beginning!!
