0:00
Good day.
My name is Marc Veldhoen.
I'm a professor of immunology at
Lisbon University in Portugal.
Today's subject is tissue
resident memory cells.
We will get a closer look
at how they are defined,
how they develop, and
what uses they have.
0:16
I'm going to limit
myself to CD8 T cells.
These are the most defined
tissue resident memory cells.
These are the cells that
provide protection against
infections by
intracellular pathogens.
The most common are
viruses and bacteria,
but also protozoan parasites.
Think about the
malaria parasite.
Lastly, and not unimportantly,
they also provide
protection against tumours.
We will go into that
a little bit later.
0:41
There are two main
T cell subsets,
CD4 T cells and CD8 T cells.
Importantly, CD8 T
cells get antigens
presented to them in
MHC class I molecules,
that's how they get activated.
CD4 T cells get
presented through the
antigens in MHC
class II molecules.
0:60
The two main T cell subsets pick
up antigens from
different cell types.
Any cell in your body
expresses MHC class I
because every cell in your
body can get infected.
These can be recognised
by CD8 T cells.
CD4 T cells get presented
when things are eaten
by antigen-presenting (APCs).
These constantly eat, bounce
off their environment
and present themselves
before T cells.
Now, I'm going to
focus on CD8 T cells,
but CD4 T cells will
play a role because they
are really the orchestrators
of immune responses.
1:35
Just a reminder that,
during an activation,
a T cell needs several signals.
Otherwise, nothing will happen.
The interaction between
an MHC molecule,
a peptide and a T-cell receptor
does not result in activation.
This would be too dangerous,
you will need more signals.
Signal 2 comes from
co-stimulatory molecules,
of which there are
a whole bundle.
We will not go into
that today at all.
That results in the
stabilisation of the signal
and proliferation of T cells.
