Microorganisms and Health [5]: Acquired immunity and Vaccinations (A Level Biology)


Uploaded by freeeschool on 02.09.2012

Transcript:
A Level Biology: Microorganisms and Health 5 – Acquire Immunity and Vaccinations
Hi! Welcome to my fifth video about Microorganisms and Health. Today, we are going to be looking
at the different types of immunity and vaccinations.
The types of immunity that I have listed here are: innate or one that you are born with;
and the one that we are looking at today, which is an acquired. An acquired comes in
two forms. It comes in active and passive. Active is where you make your own antibodies
and passive is where the antibodies are given to you from an outside source.
The first type of passive immunity is natural. That’s where you get the antibodies from
your mother. During the pregnancy, clearly there is a link between the blood from the
mother to the embryo and to the fetus. Therefore, you get the exchange of antibodies and so
you will be born with some form of natural passive immunity.
Artificial passive immunity is where you given a jump or given a vaccination in the form
of an injection and that injection contains just simply the antibodies. The major problem
with artificial passive immunity is like anything within the body eventually gets recycled.
So the antibodies that are given to you in the injection will at some point be broken
down and therefore, it won’t be long lasting.
Active immunity is slightly different. Active is where you make your own antibodies. The
most obvious way where you would get them from or you produce them from is having being
exposed to a certain disease. For instance, when you were a kid, you have been exposed
to a specific type of cold virus. Therefore, you’ll produce antibodies that will be able
to tackle that specific type of cold virus. Since we know that antibodies are made from
B lymphocytes, and so B lymphocytes differentiate into two types: memory and plasma. The plasma
are the ones that pump out the antibodies and the memory cells are the ones that stay
in the system. Therefore, you have the memory cell there for re-infection with the same
type of pathogen.
The final type of immunity is artificial immunization. This is where scientists or doctors will take
an existing pathogen and they will strip it out, so that strips out all of the parts that
cause the symptoms of the disease and that can cause complications and problems. You
will be simply be left with usually just the antigen on the surface. What this will do
is this will promote an immune response and so hopefully, you’ll go through and make
the memory cells except when you are actually infected with the disease. It means that you
have a quicker secondary response.
There is a specific name given to these types of microorganisms that have the best: the
problems and the complications stripped down; that’s called an attenuated microorganism.
The reason why an active immunization is so important is we look back at this graph looking
at an immune response. You remember your primary response to an infection. You noticed that
there is very large period here, time in which no antibodies are being produced. It is within
this point, this is referred to as the latent period and it is within this point that a
very dangerous microorganism or pathogen can cause serious issues. The bacteria will produce
huge amounts of toxins or a virus might cause damage to specific cells.
So what you can’t afford is too long a latent period because if that is too long before
you make your own antibodies, you can therefore have serious complication and potentially,
death. By giving someone an active vaccination, what can happen is they’ll produce the memory
cells that will produce a much quicker secondary response. The secondary response produces
huge numbers of antibodies and has a much shorter latent period. This is why it is effective.
In summary, immunity can be either be passive or active. The passive is where you are given
the antibodies, either from your mother or whether you receive them from an outside source
like a vaccination. Active is where you produce your own memory cells and therefore, your
own antibodies. Therefore, you can either get it through prior exposure to the pathogen
or you can have an active immunization which is where they use an attenuated version of
a pathogen.
[end of audio – 04:29] A Level Biology: Microorganisms and Health
5 – Acquired Immunity and Vaccinations Page…1