Transcript immune response

The body’s natural defense
Against pathogenic
organisms
Nonspecific Defense Against a Pathogen –
Physical and Chemical Barriers
Salivary glands
skin
Eyelashes and eyebrows
tears
Stomach acid
mucus
Non-barrier, nonspecific
defenses
Inflammation turns
red from increased
blood flow to
damaged area
fever
Swelling indicates the body
is sending more blood and
lymph to the affected area
to help correct the injury
or fight the pathogen
Infected cut –
wbc battled
bacteria –
creates pus
Phagocytes - WBC (white blood cells)
Eat pathogens
Alert other
immune
system cells
that a
pathogen is
present
The Lymphatic System –
series of vessels carrying lymph and
phagocytes
Natural Killer Cells – WBC that
kill virus-infected cells
This target cell then dies
along with the viruses inside
it!
Interferons – small proteins that
cause normal, uninfected cells to
produce antiviral compounds that
interfere with viral replication;
they also stimulate macrophages
and NK into action.
Antigen-Antibody
Relationship
A foreign
substance that
causes the
production of an
antibody to
destroy it is
called an ANTIGEN
An ANTIBODY is
produced in response
to detection of a
foreign substance
like the proteins on a
virus or bacteria
cell.
Specific Cellular Defense
B-cell eats pathogen,
breaks it apart, and
displays its proteins on
the surface of the B
cell.
Helper T cell, plasma
cell, and memory B
cells then are involved
in the antibody
response and
remembering it for the
next time.
1. Macrophage (white blood cell)
consumes a virus.
virus
macrophage
2. Macrophage digests virus and
displays viral antigens on its
surface
Antigen
3. One helper T cell recognizes
the antigen and binds to the
macrophage
Helper t cell
4. Chemicals (interleukin-1 and tumor necrosis
factor), made by the macrophage and others
(interleukin-2 and gamma interferon) made by the
T cell, allow intercellular communication
5. These chemicals instruct other helper
T cells and killer T cells to multiply. The
B cells multiply and produce antibodies.
Killer t cell
antibody
B cell
Helper t cell
6. Killer T cells destroy cells that have
been infected by the virus (and
unfortunately some uninfected cells, too)
Killer t cell
7. Antibodies released by B cells binds to
antigens on viruses – this makes it easier for
macrophages to eat the viruses and helps
destroy the viruses themselves.
8. When infection is controlled, suppressor T
cells stop the reaction. Memory cells remain
to respond quickly if same virus attacks again
Memory
b cell
Suppressor t cells
Memory cell
Allergies – the immune
system makes a mistake!
• Triggered by noninfectious agents such as
pollen or pet dander
• Causes an inflammatory response that could
be runny nose, sneezing, wheezing, hives,
etc.
• Can be developed after years of exposure to
the allergen – the body seems to reach a
critical exposure level.
The End