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T cells fight infections in our bodies
They spot attack and killing invading viruses and bacteria
but sometimes certain T cells can mistake our bodies'
own proteins for target. This is the case in people with type 1 diabetes
for reasons that are unclear those T-cells
get activated and they get turned on to attacking beta cells.
Dr. Tom Serwold's lab at
Joslin Diabetes Center aims to better understand T cell development and
education
you can think of T cells as sorta like policemen in that they
constantly traffic throughout the body and they
interact with lots of other cells and lots of other tissues
and they're actively searching out for cells were infected with bacteria or
viruses. They use discarded remnants of protein stuck to the surfaces
of infected cells as signposts letting them know which cells to strike
T-cells learn what to fight and what to ignore in a small organ called the
thymus
found in the upper chest behind the breastbone. There, T-cells learn from
their teachers
or thymic epithelial cells which proteins are supposed to be in the body
and which should be targeted. For example in the thymus
teacher cells present the T cells with insulin. Serwold: that enables the T cells that
are developing
to become educated
to insulin and so the
T cells that can react to insulin are generally eliminated within the body
the T cells that respond to the bacterial and viral antigens
are
the so-called good T-cells
so they should get the okay signal and leave the thymus
Narration: in type 1 diabetes T-cell education goes wrong in the T cells primed to go after
insulin get released into the body
these mis-educated T-cells locate beta cells
and destroy them and so are my lab is trying to do is try is
we're studying that process and with the goal
of trying to enhance the
deletion of T-cells with receptors
that can attack beta cells. We think if we could make the
thymic epithelial cells express more insulin or other
proteins that are specifically expressed normally in beta-cells
that we could increase the level of tolerance to beta cells
and decrease the likelihood
of a T-cell talk on beta cells.
One experiment looks to capture the beta-cell sensitive T-cells so their
exact molecular makeup can be further studied
Martin: We're going to place something called trap
which is a small like tablet which you put inside the mouse
and there, T-cells home to this and then we can take the T cell from
there
and study them in detail and what is really interesting
if you can move into humans and study T-cells there
then we can see what initiates type 1 diabetes
and the recurrence and other mechanistic studies
which would eventually lead us to possible therapies
because we would understand how these T-cells
attack the beta cells. Narration: if a treatment to reeducate T-cells comes to fruition
it could be applied before beta cells become destroyed or just after type 1
diabetes diagnosis in the hopes that some beta cell function will be
preserved
and along with beta cell transplantation t-cell therapy would be
one of a two-pronged approach to a cure
Serwold: what my lab is working on is to prevent the autoimmunity
and so that's one wing. And we think that's going to be highly complementary to
the other wing
which is the beta-cell replacement but it's gonna take both