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0:00
This is
a Henry Stewart talk,
and I'm John Forrester from the
University of Aberdeen, Scotland.
My presentation is on
dendritic cells in the eye
and their role in the
ocular immune response.
0:13
Dendritic cells were discovered
by Ralph Steinman in 1973.
Steinman and Cohn reported this
in the Journal of Experimental
Medicine of a novel cell type in the
peripheral lymphoid organs of mice.
Later Ralph Steinman identified
these as the most potent antigen
presenting cells promoting
the adaptive immune response.
And he also later
identified them, in fact,
as having a major role in
homeostasis of the immune response
by promoting non-responsiveness to
immune stimulation, i.e. tolerance.
For this work he had
international recognition in 2007
with the Lasker Award,
and most recently
has been awarded the
Nobel Prize for this work.
1:01
The ontogeny of dendritic
cells is interesting.
They arise as
hematopoietic precursors
as stem cells in the bone marrow.
And the lineage of these, of
course, is to produce macrophages
and a subset of
myeloid dendritic cells
called, conventional dendritic cells.
There is also a smaller population
of CD34 myeloid precursor
cells which enter the bloodstream,
and these may produce
a subset of cells
called the plasmacytoid
dendritic cells.
There has been a suggestion
that this other cell type,
the plasmacytoid
dendritic cell, may also
arise from a lymphoid precursor.
But it's generally believed that
in fact, this is not correct,
and most of this small
subset of dendritic cells
arises from the bone marrow.
Whether or not the
plasmacytoid dendritic cell
has a separate lineage from
the conventional dendritic cell
is unclear, but they
certainly do appear
to have specific and selective
transcription factors,
such as the E2-2
transcription factor,
which is, in the absence
of this, the possibility
that the plasmacytoid
dendritic cell can revert
to a conventional
dendritic cell might arise.
