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0:00
Hello, my name is Danna Philpott and I'm
an assistant professor in the Department
of Immunology at
the University of Toronto.
In this lecture, I'll present an overview
of host microbial recognition systems and
how they impact on host immune responses.
0:15
This slide provides
an outline of the talk.
First, I will give a general
introduction into innate immunity,
looking at the function of Toll-like
receptors and Nod-like receptors.
We will examine specifically the role of
Nod-like receptors in microbial detection.
In the second part of this lecture, we
will examine the link between innate and
adaptive immunity,
focusing on how innate signals
drive the adaptive immune response.
0:39
Before delving into a detailed
discussion of innate immunity,
I think it's first useful to compare and
contrast innate versus adaptive immunity.
The innate immune system has been
conserved throughout evolution and
is present in all multicellular organisms.
The adaptive immune system,
on the other hand, is fairly recent, and
it's uniquely present in invertebrates.
In innate immune system,
organisms possess a set number of
germline encoded recognition receptors.
And this is in contrast to the adaptive
system where somatic rearrangement of
genes allows for the generation of a vast
number of recognition receptors or
antibodies that can recognize the infinite
number of antigens that are present in
the environment.
Cells of the innate system
are immediately able to recognize and
react against microbes, whereas the
adaptive immune system requires priming.
Finally, the innate system has no memory
which is unlike the adaptive system which
provides a memory of infection.
1:33
Eli Metchnikoff in the early
1900s first described phagocytes,
one of the key cells
involved in innate immunity.
He watched as these cells that he
had isolated from starfish seek
out foreign substances and engulf them.
He and many more scientists after him
questioned how these cells can recognize
that particles are foreign.
