Interviewer: Professor Klenerman,
thank you for
recording this interview with
us on the very important topic
of how the immune system is fighting this
new coronavirus strain called SARS-CoV-2.
To start this interview, I'll ask you: how
does the immune system fight the usual
coronavirus strains, and
how is this new strain different?
Prof Klenerman: That's a good question
and I'll break it down into little bits.
The immune system has evolved to
fight viruses of any kind, and
coronaviruses and influenza and
other respiratory viruses are definitely
some of the things that have
driven our evolved immune system.
The first thing that happens when a virus
invades a cell is that you get something
called an 'innate response' to the virus,
and that's triggered by the ability
of the body to sense things that are
dangerous, things that shouldn't be there.
So there are components of the virus,
particularly the way it copies itself that
lead to structures that
are alien to normal cells,
and that is very sensitively
reacted to by the body so
a small amount of virus can
trigger a pretty brisk response.
That can happen quite quickly and
it puts all the cells in the location so,
say, the lining of the nose or the upper
airways onto some kind of alert, and
that has two effects, the first is that
the cells themselves can start to generate
mechanisms to fight off the virus, and
they can do that in a number of ways.
Essentially there's a massive
response within the cell,
particularly driven by a set of
small molecules called interferons,
which were discovered
about 60 years ago now.