Transcript B cells

Welcome
Immunity
The Body’s Three Lines of Defence
First line of defence
-skin; acid secretions of skin
-lysozyme- enzyme in tears saliva mucous secretions,
perspiration
-cilia(in respiratory passage) mucus
-acids in stomach
Second line of defence
-leukocytes – granulocytes and agranulocytes
-inflammatory response- swelling, heat redness, pain
-relies on phagocytosis
Third line of defence
-lymphocytes T cell and B cell
-antibodies
The Invaders
The bacteria and virus invaders shown in
the pictures have specific shapes. On
their surface they have something called
markers. These markers identify the
bacterial cells and viral particles.
IMPORTANT: Viruses are not cells- they are
not even considered to be living things
A virus utilizes its markers to mimic
other chemicals that are readily
pulled into the cell via the cell
membrane. Hence, receptors that
normally act to attach and engulf a
particular hormone or nutrient pull
in the invader instead.
Poisons (shown as red triangles)work in
a similar manner to the virus, being
engulfed by particular cells
Protists that invade the body often
evade the immune response because
they lack cell surface markers
Help, I’m getting sick!
Bacteria cause diseases like: diptheria, gonorrhea, syphilis impetigo, scarlet fever,
lyme disease, whooping cough, tuberculosis, lysteria, botulism, and the serious
bacterial meningitis
Viruses cause infections like: influenza(flu), colds, cold sores,
mononucleosis, chickenpox, herpes, warts, measles, mumps,
polio, viral meningitis, rabies, and hepatitis
Fungus cause infections like: athlete’s foot, ringworm
Protists cause infections like: sleeping sickness, malaria
Invertebrates can cause infections like Dracunculias (Guinea
worm disease),pinworms or intestinal disease worms
Poisons cause organ damage with chemicals like: snake or spider venom
Antibiotics
Don’t expect to get
antibiotics to clear
up the flu or a cold
REASON: Antibiotics
only destroy
bacteria not
viruses
Did you know?
Drinking contaminated water in Africa can lead to Dracunculias or Guinea worm
disease. This worm grows in your body, enters the bloodstream, dissolves your skin
and sticks its end out to lay eggs when your foot is in water.
The painful, burning sensation
experienced by the infected
patient has led to the disease
being called "the fiery serpent"
Infection does not create immunity.
As with many of these invertebrate
infections, the worm has no antigens
Extracted is done by wrapping it
slowly around a stick so as not to
break the worm
Did you know continued
Why have you brought us...to die in the
wilderness? For there is no food and no water …
And the Lord sent fiery serpents among the people,
and they bit the people... make a bronze serpent set on
a pole... and he or she immediately was healed.“
Numbers 21:4-9
Today’s medical symbol is derived from the snakes of the rod
of Ascelpius (likely Guinea worms) being wrapped around a
stick for removal. A very early medical technique
documented by ancient scripts, and probably even the bible
as referenced above.
Introducing the
blood cell team
All these cells are created in the bone
marrow.
The erythrocyte (red blood cell) is
strictly involved in carrying oxygen .
Thrombocytes are cell
fragments involved in blood
clots
THE DEFENCE TEAM IS:
MACROPHAGES- derived from
monocytes : both are phagocytes
(cell eaters)
LYMPHOCYTES – specifically
T lymphocytes = T cells
B lymphocytes = B cells
Killer T cells and
Suppressor T cells
The macrophage
Hi, I’m the macrophage and I eat the
foreign invaders. Here you can see me
eating a blue bacillus bacteria with a
purple antigen on top.
I will destroy this invader and pass
the important antigen marker on to
the helper T cell.
I’m doing my job and I really like
eating these invaders (It’s like ice
cream with a cherry on the top) but
there are just too many of them for
me to stop the infection on my own.
I need help !
MAKING THE ANTIBODIES
• B cells are activated by helper T cells when
provided with the antigens of the invaders.
• B cells then will make specific antibodies.
• In order to speed up the manufacture of
antibodies, B cells differentiate(mature) and
divide into plasma cells that produce antibodies
very quickly.
• Even after the invaders are gone, memory B cells
remain that can immediately produce antibodies
upon re-infection with the same invader
The Antibody
B cells produce antibodies
Antibodies are made of protein and
have a “Y” shape
The ends of the “Y” act like claws
that are specific to invader markers
called antigens
Each antibody is specific to a
specific antigen
The antibody attaches to the
antigen on the invader surface,
disabling the invader
THIS BULLET HAS
YOUR ANTIGEN
NAME ON IT YOU
INVADING PUNK! GO
AHEAD, MAKE MY
DAY.
The Antigen-Antibody Complex
Here the antibody has
captured and disabled two of
the blue bacillus bacteria.
Notice that the arms of the
antibody have a specific
shape that matches the cell
surface proteins (markers)
of the bacteria
Now that the invaders are disabled, they
can’t attack cells. In a little while they will
be engulfed by the macrophage. In the
meantime, they can’t cause any trouble
Hey let us go! We didn’t
do nottin’!
The defence team in
action
1. Invaders enter body
2. Macrophages eat
some of the invaders
3. Macrophages pass the
antigens to the helper T
cells
4. Helper T cells produce
lymphokines to attract B cells
and initiate inflammation
5. B cells receive antigens
from T cells , and become
activated
6. B cells divide to make
plasma cells that secrete
antibodies
7.Antibodies attach to
invader antigens disabling
them
8.Macrophages engulf complex
ANTIBODY
Detailed
here is the
formation of
the
antibodies
by the B
cells
B and T Cell Interaction
In this diagram, start in the
lower right corner with the
macrophage.
Here, the macrophage
displays the antigens
which are picked up by
the T cells.(blue circles)
The T cells then
produce lymphokines
and attract the B cells
(yellow circles)
With the antigen
necessary to identify
the invader, the B cell
is ready to produce
antibodies.
B Cell Proliferation
Once a B cell is
activated it must
produce large
amounts of
antibodies. The best
way to accomplish this
is to create many
antibody factories.
These are clones of
the original activated
B cell.
Clonal selection of Lymphocytes
Here you can see
that although there
are many different
B and T cells, only
certain ones display
the specific
receptor. This
identifies them as
being able to make
antibodies to
combat the current
infection and attach
to the antigen
B and T cells are originally
made in the bone marrow
from stem cells.
B and T Cell Origin
These immature cells
enter the thymus or
lymph nodes and
change (differentiate)
Cells in the thymus gland
turn into T cells ( that is
where the T comes from)
Other immature
lymphocytes develop
into B cells.
T and B cells are
transported to the
lymph nodes
Memory B cells store the info on how to
make antibodies to any disease you have
had. They retire into the lymph nodes
The Lymphatic System
The lymphatic system
drains all the fluids from
cells and gradually empties
it back into the
bloodstream
When this fluid passes
the lymph nodes, it is
inspected by the
immune cells.
The most obvious lymph
nodes are in the
underarm, groin neck
and abdomen
Lymph Node
The lymph nodes are
where the B cell
proliferate. This
causes the glands to
get bigger when you
are sick.
You can actually feel
the bumps of the
lymph nodes when
your immune system
is stimulated.
HIV Human immunodeficiency virus
HIV – Infects the T lymphocytes
Once HIV enters the body, the immune
system makes antibodies
If a person has HIV antibodies in his/her
bloodstream, he/she is HIV positive.
The HIV multiplies itself inside the T cells.
Once the cell is filled, the T cell bursts
releasing thousands of viruses. These
viruses move on in the bloodstream to
infect other T cells.
Since the T cells are the targets of the
HIV, the ability to activate the B cells
with appropriate antigens is inhibited .
The person cannot make antibodies
to any invader, thus the immune
deficiency.
The Immune System
In the immune
system the killer
T cells check the
cell markers to
see if they are:
Virus infected cells
Cancer cells
Graft cells such
as cells in a
kidney
transplant
Killer T cells will not
detect graft cells if
the person is given
immunosuppressive
drugs such as
CYCLOSPORIN
Killer T cell stops virus!
In this diagram a killer T cell
has identified a cell that has
been taken over by a virus and
is now full of virus cells.
This cell will be destroyed
and thus the virus inside
will also be destroyed.
Auto immune disorders
Mutated T and B cells may incorrectly identify normal
cells as harmful.
The action of these cells is normally stopped by the T
suppressor cells. If they continue auto immune
disorders result
Examples of auto immune disorders are:
Rheumatoid arthritis, where an immune response is mounted
against the bones and connective tissues surrounding the joints
Rheumatic fever, which scars the heart muscle
Lupus where antigen–antibody complexes build up
in the walls of blood vessels, joints, kidneys, and skin
Multiple sclerosis (MS) where T cells of the body initiate an
attack on the myelin sheath of nerve cells
Allergies
Allergies occur when the
immune system mistakes
harmless cells for harmful
invaders.
Remember, no perfume
in the classroom!
Severe allergic responses can
constrict the respiratory tractpossibly causing death.
Epinephrine (adrenaline) can be
administered with your epi-pen
by your teacher
Intermediate Reaction Allergy
The immune system
produces antibodies to non
harmful substances like
pollen , cat saliva and dust
mite droppings.
These antibodies attach to
mast cells.
When the allergen attaches
to the mast cell antibody, it
causes the mast cells to
release histamine.
Histamine causes the
symptoms typical of
allergies. Ex. congestion,
runny nose sneezing, itchy
skin, headache, increased
heart rate anxiety and
agitation
The end