hi and welcome to today's video where
we will be discussing antibody structure and function within our immune system. specifically, in this video we are going to be
talking about the adaptive immune system. if you want to learn more about the difference between
the innate and adaptive immune system you can find the video called elements of immunology
but today we're going to talk about specifically antigens and antibodies within the adaptive immune
system so within this part of our immune system we have to be able to target specific pathogens
and to do this our immune cells recognize things called antigens or they're also called
immunogens antigens are a specific molecule that's present on the outsides of pathogens such as
viruses bacteria or fungi so in this figure here we have a virus and these little protrusions here
would be our antigens on the outside of the virus and then what our immune cells will do is our
immune cells have things called antibodies or immunoglobulins and antibodies will look for and
attach themselves to the antigens and then once they bind to the antigens they signal for other
immune cells to come and attack so here in this figure we see in the blue we have our antibodies
and the antibody here is bound to the antigen and then this will then signal the alarm
for other cells to come and kill the virus specifically antibodies are composed of
this structure which looks like a y shape and this structure helps with its function
so the first function of the antibody is to bind to antigens and so this top part of
the antibody the top part of the y is the fragment antigen binding or the fab fragments
and so this is where it binds to the antigen the second function of an antibody is
to then activate activate the defense so signal the alarm for other immune cells to
come and kill the pathogen and this is where the the bottom part of the y or the fragment
crystallizable region or fc region is important looking a little bit deeper into the antibody
structure antibodies are composed of four polypeptides and a polypeptide is a formation
or a string of amino acids amino acids are the building blocks for proteins and specifically
antibodies are made of two light chains and two heavy chains and so these two light
and two heavy chains form the four polypeptides and so here in red we have the heavy chains
and then in purple we have the two light chains on top of that antibodies have both
a constant and a variable region so here in the darker shade of purple and red
we have the constant region of the antibody and then in the light purple or the light red we
have the variable region and so this variable variable region will change or be very
diverse between the different antibodies as they're aimed at targeting
a different range of pathogens so to be able to specifically target different
pathogens it has these highly variable regions within the fab fragment that i just mentioned
so this top part of the antibody we have the both the variable region in
both chains and the constant region but the fc region is just made of the constant
region of the heavy chain and so this is the part of the antibody that is usually interacting or
within the cell membrane of our own immune cells now antibodies come in five main forms
or families and they are the igg igm iga ige and igd and they mainly differ in
the type of heavy chain that is used so while they each have at their core this y
shape the y shape can be composed or created into other shapes such as shown here and here
and they're also usually found in different parts of the body and while these antibodies are
specifically aimed at fighting different pathogens they can be generated at the same time or they can
also be generated at different time points of your same immune response so you have a pathogen maybe
one antibody will be generated and then another we will then be generated afterwards
as part of the same immune response and so really we have this very diverse um form
to act against defense against all these different specific pathogens such as certain viruses and
bacteria and this is constantly evolving within our bodies and so it's quite amazing how we're
able to fight off all of these different pathogens and that is it for today.
i hope that you found
this video helpful if you want to learn more about antibodies or our immune systems or even
our own bodies please subscribe for more!.
