Yeah,
yeah,
yeah.
Mm.
Mhm.
Are you healthy,
then?
Inside you,
a ceaseless but successful struggle against invaders
such as bacteria and viruses is raging
every day. Our bodies are attacked by villains like these.
You mostly don't realise it's happening,
because before the villains can do any damage,
they are tracked down by our immune systems and rendered harmless.
But sometimes the immune system overshoots the
mark and starts attacking our own body.
And then the result is auto immune diseases.
The body attacks itself.
Mhm.
A doctor.
You come across lots of patients whose immune system is not working properly.
Just think of diseases like multiple sclerosis or diabetes.
And these serious diseases challenge us to understand exactly how the
immune system functions in order to find ways to cure them.
The physician, Thomas Berm,
and his team at the Max Planck Institute of Immuno Biology and
Epigenetic in Freiburg are investigating how the immune system fights invaders.
They are especially interested in what is known as adaptive immune defence,
a characteristic only vertebrates possess.
It is particularly effective at fighting against Germans.
Yeah,
and these are the main actors in our adaptive immune defence,
B lymphocytes
and T lymphocytes.
These white blood cells work with the other cells of the immune system, for example,
with the scavenger cells, their common enemy, the bodies in other words,
the bacteria and viruses.
Mhm.
Once the intruders have been spotted,
the T lymphocytes sound the alarm.
They activate the B lymphocytes.
The B cells mark the intruders with antibodies.
That makes it easier for the scavenger cells to recognise and destroy them.
Yeah,
what is more, or T lymphocytes patrol the body on the lookout for germs,
which are hiding there.
But they may only attack infected cells and must leave healthy cells in peace.
Otherwise, dangerous autoimmune diseases may develop.
The scientists want to know what enables the immune cells to act so specifically.
To do so, they need to examine how and where they develop.
In the higher vertebrates, T cells develop in a special place. The thymus gland,
the thymus gland, lies here, behind the breastbone and in front of the heart.
We can imagine the thymus gland as a sort
of school in which the important immune cells,
the so called T cells, are taught how to recognise germs and to destroy them.
It's as if the precursor cells had to go to school like a primary school
and then acquire information in school,
which they will need afterwards in order to function.
So first of all, the immature T cells have to be trained.
This happens in the thymus school
here. They learn which pathogens they should fight
and that they should leave the body's own healthy tissue alone.
To make sure they do this, they have to pass several tests.
This is known as positive and negative selection.
Only those that pass can leave the school and join
the immune defence troops as a mature T lymphocyte.
Mhm.
Those that make mistakes are eliminated. So how does this work in detail?
As you can see in humans and other animals,
the famous school is very large and complex and has
lots of classrooms in less complex creatures like the lamprey.
Such a school does not exist, and the question is,
where do the precursor cells receive their education inside a lamprey.
In evolutionary terms, the lamprey belongs to a very old group of animals,
but it also has an adaptive immune defence system.
So where are the T cells trained? If it has no theme is gland.
In order to understand how the precursor cells mature.
The lamprey is therefore an ideal model organism.
The latest research findings show that special genes play a
central role in the training of the T cells.
Thomas Bloom discovered one of them himself.
The folks in one gene is so to speak. The headmaster of the
school, They said Master ensures that the training functions in an orderly manner,
and he determines the rules.
And he also ensures that the primary school pupils
enter the school and get the training they need.
But the training also needs teachers. So here we have a teacher called CDA one,
and this
one gene makes sure that the precursor cells
and the pupils get the information they need
in order to fight off the germs later on.
So our question was, where in the lamprey is this T cell school actually located?
The idea as to how to answer this was quite easy.
We said it must be where the headmaster and
the teacher of both active in the same place.
The scientists produce ultra thin tissue sections
by means of what is known as in situ hybridisation.
We can make visible locations in the tissue where a specific gene is active.
The scientists want to use this technique to track down the
place where the two genes they are looking for Fox,
N one
and C D A. One are active.
You can imagine the entire procedure rather like this.
If a gene is active, it is copied, thereby producing its own mRNA.
This applies to both Fox and One and CDA one.
The scientists make some artificial R N A,
which is a mirror image of the M r N a of the gene.
Then they put these artificial strands of
RNA on two different tissue sections of the lamprey.
So on one section they put a fox n one m r n a.
And on the next they put an M R N A of CDA one.
If the probe's encounter the original mRNA, they will combine with it.
The blue dye marks the place and makes it visible for the scientists.
If they place two sections treated with different, mRNA is on top of each other.
They can find out the place where the blue markings overlap,
and that must be where the school is
after three days. The time has come.
Now they can see where the lamprey also have a sort of training school.
The scientists search under the microscope for tissue which
has been dyed blue by the fox N one
and the CDA one probes
and indeed they find just that On the tip of a gill filament,
they discover the lamprey school for T cells.
The surprise is that there is not just one blue place, but many
that can mean only one thing.
Lampreys have not just one, but many schools for T cells.
They are found on the inside of their gill openings.
Many experiments now indicate that invertebrates, the adaptive immune system,
developed twice during the course of evolution
and 500 million years ago, also in the lamprey.
But they're the school for T cells is not as large and as complex as ours.
It consists of one room schools.
And the interesting thing about this discovery was that these
little one room schools have a headmaster and a teacher,
just like the big school we know in humans.
And the precursor cells are trained in this one room school,
just like the ones in our big school.
Such comparative investigations enable them to find out more
and more about how our immune system functions.
And they have a fascinating vision
at the moment.
We're working on how to use this knowledge to create
new functions artificially through the function of these individual genes.
That means to produce artificial organs,
which can compensate for or improve certain malfunctions of the immune system.
Normally, our immune system is like a powerful team that works very well together.
But sometimes things go wrong.
And that is when in future,
the scientists want to be in a position to step in.
Uh huh,
Yeah.
It was
mhm.
Uh huh,
Yeah,
yeah.