Hello students, my name is Jason Key and
I'll be your instructor for the
Immunology course this semester. You can
find notes in blackboard and please
follow along with those, and let's go
ahead and begin with Lecture 1,
Introduction to Immunology. As a student,
how would you want to approach this
course? A lot of students have not had an
immunology course before, so the first
thing is to always ask questions. If you
have any specific questions about a
specific concept, then please reach out
to me. Email me or give me a call at the
office. I'll be happy to explain this
procedure or concept to you further.
Please read the syllabus, and again if
you have any questions feel free to
reach out to me. All the material
that you need for this course is in
blackboard, so take a few minutes and go
through the blackboard course and
familiarize yourself with everything
that is available to you in the
blackboard course. We will have weekly
quizzes so please be mindful of that.
I would write them down on your program
calendar that you have been given.
Also, any missed or late assignments or
quizzes will receive a grade of zero
after the due date. So please do not
miss those, those are easy points. So if
you have any questions feel free to
reach out to me. During this course this
semester, we'll be discussing
basic concepts of immunology and the
human immune response to certain
infections. This could be bacteria,
viruses, fungi, or autoimmune. And you'll
also be able to understand key concepts
of immune based diseases
to include autoimmune and certain
bacteria and virus infections. You'll also be
able to recognize the importance of
Immunology in the clinical laboratory. So
Immunology- a lot of labs now do not have
a specific immunology department. Some
do,
most do not. So immunology kind of got
absorbed into the rest of the laboratory.
So this kind of brings us to- you'll be
able to correlate the interdependency
of immune response and the study
of immunology with other laboratory
disciplines. So, you know, when you think
about blood bank, you're testing
for ABO. That is similar to a serologic
test or an immunology test.When you do,
let's see, C-diff testing, rapid C-diff testing in micro, that is an Immunology
test. So as the course goes on
you'll be able to pick up on each
each of these tests, and how it kind of
correlates with other departments in the
laboratory. During this lecture, we're
going to be going over the history of
Immunology, some terminology that will be
used throughout the entire course this
semester, and then we'll kind of get into
the meaning of immunology, by first going
over the seven main concepts of immunity,
and then we're going to be stating some
characteristics of innate versus the
acquired immune system.
So let's start off the lecture with a
question. What is the number one cause of
overpopulation?
So the answer? It's vaccines. So with the
decline in the death rate due to
vaccines, and a lot of these diseases are
not killing people as they once did,
we have a decline in the death rate, and
of course, we are still breeding like
rabbits.
So this has a lot to do with the
overpopulation of the earth. It's not the
total thing, but vaccines do have a lot
to do with it. So if we're thinking about
immunization or vaccination, basically
we're being injected with an antigen to
cause an immunity by inducing a
protective immune response.
It could be against a bacteria or a
virus, typically it's a virus. So we take
a substance from that particular, let's
say, virus. Let's talk
about the flu for a minute. So we take a
piece of this flu virus and then we mix
it with some adjuvants, and we'll speak
about adjuvants in later lectures, but
it's a mixture that we mix in with the
piece of the flu virus, and then we
inject it into our bodies. And then our
bodies will have this immune
response and start producing
antibodies to this piece of virus that
has been injected. So if we come into
contact with it later, then our immune
system will identify it, know what it is,
and then we potentially will not get
sick. So that is the basic function of a
vaccination or immunization. It's to help
us prevent from getting sick with a
specific type of antigen, or virus, or
bacteria.
Another good representation of
vaccination or immunization is the polio
virus. We could also use smallpox virus
which has been predominantly eradicated.
The polio virus is almost at the
eradication level. I believe there are
two or three different countries who
have nearly seen eradication, but they
still have little pockets of polio
that's popping up. We'll
go over the areas in the next slide, but
you can see the dramatic decrease in
cases reported once that polio vaccine
was discovered and put into place. So the
cases dramatically dropped over the
years, and soon we will have complete
eradication of the polio virus. This map
you find on the CDC website.
Basically polio has almost been
eradicated but in three countries, and
those are Afghanistan, Pakistan, and
Nigeria. So you can see in 1988 when it
first became a pandemic, the polio virus
was spread throughout much of
Asia, Africa, northern South America, and
in Central America. But now, since the
polio vaccine has been distributed
worldwide, we just have these little
pockets of polio viruses popping up here
and there, and it's basically in what we
consider third world countries, where
access isn't what it should be. But there
are many many organizations who are
trying to pump the polio vaccine into
these areas to help them try to eradicate
this potentially deadly virus. So your
first definition of the course, is the
course itself.
Immunology. So what is Immunology? It is
the study of a host reaction when
foreign substances are introduced. So
basically, how do we react when a foreign
substance comes into our body? That is
the study of Immunology. We want to know
what happens to the body when something
is introduced that doesn't belong.
So this brings up a question that
I'd like to talk about. When you go see
your PCP, what is one of the first few
questions that the PCP will ask you?
It's basically "are you allergic to
anything?"
Mainly because if something is wrong and
he can help treat you or give you a shot,
he doesn't want you to have a reaction
to that particular antibiotic, or steroid,
etc. So that is one of the main reasons
why they ask you, "are you allergic to
anything?" They don't want any adverse
reactions. Let's go ahead and begin and
learn a little bit about the history of
Immunology. So Edward Jenner would be the
first person that would come to my mind
when we're speaking of Immunology.
I would consider him to be the founder of
Immunology. He was an English
country doctor back in the 1700s, who
actually came across the vaccination, or
invented the vaccination, for smallpox.
He did experiments that are unethical by
today's standards, but proved to be
beneficial for mankind, and will speak a
little bit about
his experiment in the next slide.
Edward Jenner lived in the mid to late
1700s right when smallpox was becoming a
massive pandemic. He wanted to help stop, or get rid of the
smallpox from affecting his countrymen.
He basically observed and recorded
23 cases, and while he was observing
these cases, he noticed that milkmaids
were not contracting smallpox. And upon
further investigation he learned that
these milkmaids once came in contact
with cow pox, which is a very similar
virus. So he wanted to do basically, an
experiment. So he got a milkmaid with
these pus lesions from cow pox,
and basically took some pus out of the
pus lesion and injected it into a young
boy,
James Phipps, who was actually eight
years old at the time. He injected Mr.
Phipps here with the pus lesion. A few
weeks later they then exposed him to
smallpox, and he did not develop the
disease. This is what led to the
vaccine for smallpox. Being in the 1700s
obviously this did not raise any ethical
concerns, but in today's standards there
would be no way that this would be
approved by any any sort of research
individuals. A couple questions-
Would you volunteer your own child
for this experiment, even if it was
potentially for the greater good of the
world? Or, could this experiment be
reproduced today? Obviously absolutely
not.
There are too many regulations in this type of
research parameters that we have
especially in immunology and mainly
children. So that would
definitely not happen today.
Even though it was unethical, it
did lead to what we consider a greater
good, and ultimately elimination of
smallpox. So a good thing did
come out of his research, and there are
many more who've developed vaccines
throughout history, I listed a couple
at the bottom here. Ian Frazer, the most
recent with the HPV vaccine, and there
are a couple recommended readings
if you want to figure out anymore who've
made history with their vaccine
discoveries.
Now let's take a look at
a couple more definitions. Immunity, serology,
antigen, antibody, and epitope. So immunity.
What is immunity? It's
basically the ability of an organism to
resist a particular infection.
So when we have immunity, we will not be
getting sick to a specific type of
organism because we have
antibodies to that specific organism
that prevents us from getting sick.
Serology. It's basically the study of
non cellular components in our bodies, in
our blood, and these include antigen and
antibodies. So antigens can also be
called immunogens. I will be
using those interchangeably throughout
the course, so please know those two. It's basically a foreign substance that
induces an immune response.
So antigen would be like a bacteria
getting into our bodies, and that would
be considered an antigen or an immunogen.
An antibody, or an immunoglobulin. Those
will be interchanged as well. Please know
both. It is a glycoprotein made a
response to an antigen, so when that
foreign substance enters our body, our
body will combat it by producing
antibodies to attach to the surface of
this antigen. So that brings us
to the last definition which is an
epitope. An epitope is the antibody
binding site. It is one single
antigen site. So, many antigens have
multiple epitopes, but the antibody only
really needs one epitope to bind to.
Once this antibody binds to this epitope, then it
is marked and it is ready to be
engulfed by a macrophage or neutrophil.
So this the signals this antigen to
for destruction.
Here's an example of an antigen. So the
entire thing, including the epitopes, is
considered to be an antigen. It's
basically a bacterial cell, so one
bacteria is considered to be an antigen.
These epitopes that are on this
bacteria, on the cell membrane of the
bacteria, can all be different. And we can
see that there are antibodies.
These antibodies are specific to a
certain type of epitope. There's only
one epitope that these antibodies are
specific for. So once these antibodies
are made, they're out there finding that
one epitope that they were
made to find, and if they find it they
will bind and then tag this bacteria for
destruction, or deletion, or to be
phagocytized. We'll
spend a great deal more talking about
the antibodies and antigens and
epitopes coming up. So what is the role
of the immune system? The the
very basic, basic role of the immune
system is to eliminate infectious agents. It's designed to protect us from
pathogenic invaders. This includes bacteria viruses, etc.
It helps to recognize tissue grafts, or
newly introduced proteins like poison
ivy. If we get if we get a severe burn, we
have to get a tissue graft, and depending
on how our immune system reacts to that
tissue graft- will it reject it or will it
allow us to accept that tissue graft. It also
defends against tumors. We have
natural cells that actually attack
tumors. So our immune system
is one of our biggest allies in the
defense against outside invaders of our
bodies.
What type of pathogens can the immune
system recognize or protect us against?
Basically, extracellular, intracellular,
viruses, parasitic worms. Pretty much
anything that is foreign, the immune
system can help us get rid of.
This includes pneumonia, candida, malaria.
For intracellular bacteria parasites- malaria leishmaniasis. Viruses
including chickenpox, the flu, small pox.
Now the coronavirus that's been going
on here recently. Parasitic worms like
schistosomiasis,
Ascaris lumbricoides. So the immune
system plays a huge role in our bodies
in helping to eliminate these types of
pathogens from our bodies.
So let's look at some main concepts of
Immunology. The seven main concepts. The first one is to distinguish
between self and non-self.
So we want ourselves to be able to determine what
is our cells, and what is a foreign cell,
or a non- self cell. It is very
imperative that our other cells be able
to identify our own cells and foreign
non-self cells. So main concept number
two would be that we have two overlapping
systems that we will be talking about
shortly. Number three would be
specificity, so it's very specific and
knows what to attack. It can actually
identify these different types of
parasites. Number four would be diversity. This kind of comes back to
our antibodies. Remember, our antibodies
can only identify one epitope, one type
of epitope, but we have billions and
billions of antibodies with different
epitope structures that they can
identify. So this kind of helps play into
our diversity of our immune
system. Clonal selection- we'll briefly go
over that. Memory. Memory is big. So in
Immunology, memory is basically what it
says. It is our immune systems
memory to help us remember if we have
come into contact with a certain type of
bacteria or virus before. That way it can
trigger the alarm bells and have a
much broader and bigger response to
attack that virus that we've already
come into contact with once before, so it will
not affect us as bad as it did the first
time.
Number seven is regulation. We have
got to have regulation in our immune
system. That is very big. We want to to go
back to your biology classes. We want to
have homeostasis.So this regulation of
the immune system helps with
homeostasis. We don't want it to
overreact, and we don't want it to
underreact. We we want it to react
appropriately, and we'll kind of talk a
little bit about that next.
Okay let's briefly go back to our our
first main concept in distinguishing
between self and non-self. So, the immune
system has very specialized mechanisms
to help us detect our own cells, our host
cells, and foreign substances or foreign
cells. This will allow our immune
system to react accordingly to what it
is detecting. Regulation kind of comes into play with
this as well. We want this homeostasis.
This immune homeostasis. We want it
to react to our non-self cells in an
aggressive manner, but we don't want it
to react to our self cells in this
aggressive manner. That could lead to-
we'll talk about this later- like
autoimmune diseases, etc. So when our
immune system reacts to these non-self
cells, we want it to react with great
speed and accuracy, but we don't want to
want it to overreact. So this is
kind of how we want this homeostasis. So
if we have an overreaction of our immune
system, this usually causes hyperreactivity. We consider this to be
hyperreactivity, and that could lead to organ
specific autoimmunity diseases, or
systemic autoimmunity diseases. Allergies
and asthma are considered to be
hyperreactivity. On the other spectrum, if it
underreacts, so it doesn't send enough
signals to our cells to attack this, then
this could be
caused by neutrophil disorders, T cell
dysfunction, or maybe even even a
complement deficiency. We consider
these to be hyporeactivity. So it's not
reacting enough. So we want that balance.
We want that immune homeostasis. That's what we're looking for in the immune system.
We could break this down further. So
let's take a look at hyporeactivity.
This is basically when an immune
response is absent from the host.
This obviously will lead to disease or
illness. SCIDS is a very uncommon
disease, but it is a good measure of hyporeactivity. It's basically a
combined immunodeficiency. So this person would have a defect in their T and B
lymphocytes. If you have deficiency
in T and B cells, which are your major
immune cells fighting these diseases,
these antigens, or bacteria and viruses,
then obviously you're going to have some
serious complications, some serious
infections. One of the
biggest examples is the bubble baby.
They have to live in a completely
sterile environment. No contact
whatsoever, skin to skin, or anything,
because they're basically
immune suppressant. They don't want to
risk any type of bacteria or viruses or
anything getting into contact with this
particular baby, because his immune
system is basically non-existent. Another
example would be HIV or AIDS.
So, HIV eventually will kill off all the CD4 T cells,
and these T helper cells, which
we'll
call them and we'll speak a great deal
about later, basically helps all the
other immune cells. So if we destroy all
the CD4 T helper cells, then we don't
have any help with the other immune
cells, so they don't know what to attack,
what not to attack, when to divide,
especially with B cells. T helper cells
help the B cells divide into plasma
cells, which this is where we get our
antibodies from. So with the destruction
of the CD4 T cells, HIV is very, very,
very bad on the immune system, and it
basically wipes out the immune system.
This is why many patients with HIV
will die of secondary infection, like
a fungi, rather than the HIV itself
killing the patient. So that's what
makes these diseases really bad. These both would be considered a
hyporeactivity type deficiency. On the
other spectrum, we have hyperreactivity,
or sometimes referred to as
hypersensitivity. This would include our
autoimmunity and allergies. This
is when our immune system overreacts and
when it overreacts it actually damages
our own tissue, our own cells okay.
The most common types of this are
rheumatoid arthritis. You can see in the
picture, this is a severe, severe form of
rheumatoid arthritis.
Typically it affects the joints, usually
the the fingers and the hands, and the
knees. Also allergies is a hypersensitivity or reactivity.
We'll talk about allergies, and especially when allergy season
comes around you'll see people with
runny noses and coughing and sneezing
all the time.
Basically the body is overcompensating
for all the allergens that they're
breathing in, and thus telling
the mast cells to release mass amounts
of histamine which causes all the
symptoms of the allergies. Also, we could
look at immunopathology or
immunoproliferative disorders. This is an example of
multiple myeloma. You can see in the
pictures with the dark spots in
the bone mass there This is significant
of what we call, lytic lesions, in
multiple myeloma, and this is highly
diagnostic of multiple myeloma. It's
basically the excessive uncontrolled
growth of plasma cells in the bones, and
these plasma cells will actually start
producing a chemical that will
actually eat away the bone mass,
and that's what creates these lytic lesions in the bones.
Our second concept, is that we
have two overlapping systems. So we have
our innate, or natural, and our adaptive,
or acquired. So our innate system is what
we consider to be nonspecific.
It's a recognition of substances
different from the self. We always
have this innate or natural response.
All healthy individuals have this,
and it's typically our first line of defense.
So this would be your skin,
your phagocytes, inflammation components
would be our innate or natural systems.
Then we can move on over to the
adaptive or acquired. This type
of system recognizes with specificity
to non-self substances. This usually
includes microbes that have invaded the
tissue or the body. It can adapt to
defend against these specific invaders,
and actually give us protection if we have prior exposure to
this specific invader. This
system involves mainly our lymphocytes
and all the products that these
lymphocytes produce, and we'll definitely
go into that in the next couple of
lectures. Our innate, or natural immune
system is primitive. Everyone is born
with this intact, in place. It's
always present, it,s an active part of
the tissue response. So, for instance,
we always have this splinter. Most of us probably have
received or had a splinter at one time
in their life. Whether it's a
splinter, or possibly a nail in the foot,
or BB, or somebody even if they got shot
through the hand, or what have you. This
response is always going to be the exact
same. It does not change. This
type of response does not have memory
either. It doesn't matter if
it's a splinter or a nail that we get
stuck into our skin, it's going to react
the same way every time. When we get an
infection or something that pierces our
exterior barrier like our skin.
Our adaptive or acquired immune system is really only found in mammals, fish,
amphibians, and birds, so we are very
lucky to have this type of immune system.
It has to be induced to
be active against certain infections or
tumors, etc. Something has to trigger it
in order for it to become active.
The good thing about this type
of immunity is that it has memory.
We'll briefly talk about that
here in just a few moments. So there are
two types of adaptive immunity, and that
is humoral and cell- mediated. And there
are two ways to get adaptive or acquired
immunity, and that is either active or
passive. And we'll look at all those in
the next slide.
Types of acquired immunity. So let's
take a look at humoral and cell-mediated.
Before I begin, this is a nice little
table. When you get to know how I teach
my lectures, you'll eventually see that I
have lots of tables and
lots of charts. I just like to have them.
It helps a lot of people learn the
material, kind of breaks it down into
chunks, and that way it'll help you study
for the exams.
Feel free to print these out and use
them with your notes to help you study
for future exams. So humoral and
cell- mediated immunity. In our humoral immunity we have our B lymphocytes
that are heavily involved, and
our B lymphocytes will produce
antibodies, and these antibodies
will start to attack the extracellular
micro organisms. Let's
remember, humoral- B lymphocyte.
B lymphocyte produces antibodies and then these antibodies will eventually
attach to these extracellular microbes
and help eradicate these from our bodies.
Cell- mediated- we have our T lymphocytes
that are highly involved. These T
lymphocytes produce cytokines and other
substances that we will soon talk about.
These are here to help
eliminate intracellular microbes.
So these substances that these T
lymphocytes produce help activate
phagocytes to help destroy these
intracellular microbes. So humoral is
B lymphocyte. Cell- mediated is T
lymphocyte. You will need to know the
difference between these two. So how do
we get acquired immunity? We can get it
one of two ways. We can either have
active or passive. So in the
active immunity, we ourselves create
antibodies to the infection, or it could
be from a vaccination. So our immune
system will respond and start creating
products, mainly antibodies, after our
initial exposure either due to a certain
type of infection or vaccination.Then we will actually start to make
memory cells of this particular
infection or vaccination that will help
us if we come in contact with this
specific type of bacteria, or virus, again
then our body will know exactly what it
is and then will start producing
antibodies to it and we'll get better
sooner, and we can take care of this
infection quicker and at a more
regulated rate. We also have passive.
So this is when somebody else
will immunize us, per se. So our bodies
will not make antibodies in passive,
so we get immunization from a different
individual or an animal. An example of
this would be mother to baby. So when a
baby is born typically it will
breastfeed, and even before it starts
breastfeeding when it was first born, the
baby will have antibodies from the mom
circulating through its circulatory system. So it has a short
term immunity from the mom. This
is what we would call passive.
We can see this in mom and babies, and even in other animals. Cows, we see this a lot
where they have passive immunity.
So our third main concept is specificity.
This is when our acquired immunity is
activated through interaction of
antigens, which are bacterial cells, and
our lymphocytes with specific antigen
receptors. So we have our B cells and our
T cells. On our B cells we have
antibodies that are on the surface of
these B cells, and remember these
antibodies, each little wing has one
specific epitope that they are looking
for.
These will actually cross link
with the epitopes on the bacterial cell
and mark it for eradication. In our T
lymphocytes we have what we call T cell
receptors and these will actually
interact with a lot of surface proteins
on bacterial cells, or what have you. We will definitely dive a great deal
further into these as this class
goes on, so I just wanted to briefly
introduce you to this concept first, but
we will definitely go into greater
detail later. Our next concept is
diversity. Our immune system is so
widely diverse, it is absolutely amazing
actually how diverse it is.
Our lymphocytes, both our B cells and
our T cells are designed with specific
antigen receptors before they even
encounter an antigen, and they go through
a DNA rearrangement to determine what
epitope,
or what antigen, they are going to
be able to detect. This is basically a
random selection of gene segments and
this random selection
results in thousands and thousands of
different variable region sequences on
the antibodies and the T cell receptors. We'll definitely go further
into this as well as the class continues.
During clonal selection, a small number
of B and T cell clones bind to the
specific antigens with, what we call,
high affinity, and will start to undergo
a transformation process. This
transformation process we call
activation, proliferation, and
differentiation. So when it binds to
these antigens it will become activated, and then it will start to
proliferate, so it will multiply or clone
itself.
Then, once these clones are going, it will
actually differentiate into other cells
like plasma cells for B cells. These
plasma cells are what makes our
antibodies. Activated T cells from regular T lymphocytes will
become activated T cells, and both of
these B cells and T cells can produce
memory cells, as well. So they'll
proliferate and differentiate into
plasma cells, activated T cells, and B and
T memory cells.
Just to clarify, B cells proliferate and differentiate into plasma
cells and B memory cells, and then T
cells proliferate and differentiate into
activated T cells and T memory cells.
This is just a brief example. So all
lymphocytes, that is our B cells and our
T cells, start out as a lymphocyte
precursor. When it gets
stimulated is when it will
either become a B cell or a T cell.
Once it's stimulated, it'll start to
undergo maturation, and this is when it
will start to develop the surface
receptors of a particular epitope.
This chart here shows on the left
hand side we have antigen X, so we have
antibodies on this B cell for antigen X,
and it will float through our body and
try to come into contact or find this
epitope of antigen X ,and if it does come
into contact with antigen X, it will become
activated, it will proliferate, and then
differentiate into plasma cells, and then
these plasma cells will create
antibodies to the initial antigen that
activated it. So these antibodies that
these plasma cells will produce will be
antibodies towards antigen X.
So our bodies will be flooded with these
anti- X antibodies once this B cell
becomes activated. On the right hand side
we have antigen Y. So this b-cell
antibody has antibodies to antigen Y, and same thing. So this B cell will
float through our circulatory system
trying to find this antigen Y, and once
it comes into contact with this it will
become activated, proliferate,
differentiate into plasma cells and
memory cells, and then these plasma cells
will start to produce anti- Y
antibodies and flood our bodies with
these antibodies to help find this
antigen Y.
The next concept is memory. So the response against the antigen is much
greater after the first exposure. So
we have two kinds of immune
responses. We have our primary and our
secondary. Our primary is the response to
the very first exposure to a specific
antigen, and this is typically mediated
by our naive lymphocyte. We say naive
because they have not come into
contact with any antigens yet, so they
are naive. This is their first time.
So this would be our primary immune
response. Then we have our secondary
response, and we also refer to this as
our anamnestic response. This is for our
subsequent encounters with that same
antigen, and the secondary immune
response is basically mediated by our
memory lymphocytes. Our memory cells
remember that we have already come into
contact with this antigen once before.
So that floods our immune system with a
higher level of response and that way we
can take out this initial antigen
quickly. Let's move on to the next slide
and I'll show you a little diagram of
what I'm talking about.
So here is the chart of our immune
response. Let's start
in the left hand side of this chart.We
have our naive B cells. We have our purple
and our green B cells.
The purple is anti- X and the green is
anti- Y. We're going through, the bottom
portion is weeks in our timeline, we keep
going and at the second week we have an
influx of this antigen X.
So our B cell who has the anti- X
will recognize this antigen and
start to create the primary anti- X
response. So we have a nice little
response. The B cells
latch on. They activate, proliferate, and
differentiate, and now after a couple
weeks we'll have memory B cells to that
antigen X. So as time progresses, we
never came in in contact with antigen Y
so we still have our naive B cell to
antigen Y, but now we have memory cells
to antigen X. So let's say at
week seven we're going to introduce our
antigen X and antigen Y and see what
happens to this immune response then. So
as we add our antigen X and antigen Y-
let's go ahead and start with our X
first- we have memory B cells.
So we've already come into contact with
this antigen so we are going to have a
more hefty, quicker response to this
particular antigen, and you can see that
in this graph. It is definitely a lot
stronger, quicker, and our memory B cells
will start activating and then our
memory cells will actually proliferate
and differentiate further into plasma
cells to start creating more antibodies
to this antigen X and more memory cells
to this antigen X. Overall it is a
much broader and much bigger secondary
response to this antigen X. On our naive
B cell with our antigen Y we see that it's
still its primary first response, so
during this introduction to antigen Y,
we're only going to have any
small response. Our primary response. So
this cell will become activated and will
proliferate and differentiate into
memory cells and plasma cells, but on our
next exposure to this antigen Y, it
will have that secondary response. It'll
have a much stronger response on
initiation of that second exposure to
that particular antigen. Our last concept
we'll be talking about is regulation.
The immune system has to have a way to
inhibit self-reactive or overreactive
lymphocytes, so we have to be able to
regulate our immune response.
We could do this through either elimination,
permanent inactivation, or inhibition.
We will be going over these
regulation terms throughout the next few
lectures.
There are some fill in the blanks after
most chapters in your notes. You can take
some time to answer those questions on
your own, these are not for a grade. It'll
just kind of help you review for the
exams, etc. You can use these lecture
slides to help review your answers.
So remember our antigen or immunogen is
the foreign substance that actually
induces an immune response, and our
antibodies or immunoglobulins are made
in response to the specific foreign
antigen. Remember, they are
glycoproteins. Epitopes- it is
that single antigen binding site on the
cell wall of, for instance, a bacterial
cell. It is a single antigen site.
True or false: the immune response that
causes immunity is associated with
natural immunity, and a key
characteristic of acquired immunity is
being antigen specific. We'll go over the
answers in the next slide.
So the immune response that causes
immunity is associated with natural
immunity- this would be false. It should
be acquired immunity. Remember, natural
immunity is the primitive immunity so
everybody's born with it but it has no
memory. Acquired immunity is either
received through active or passive.
So it's either from a previous exposure
or vaccination, or passive would be from
mother to baby. A key
characteristic of acquired immunity is
being antigen specific- this is true.
Here is a review table for you for your
notes. Please take a look at it and it'll
kind of help you study for the exam as
well.
So which is active and which is
passive?
The left-hand cow would be considered
active immunity because they are
getting a vaccination, and the right-hand
side would be considered passive
immunity because they are not getting a
vaccination or have come in contact or
exposure to the antigen so they are
getting antibodies from the first cow
either through serum injection or the
first milk as in the baby calf.
All right, this is the end of lecture 1.
