Immune Response
Chapter 40.2
What makes you sick?
• Bacteria
• Viruses
Antigen
• Both bacteria and viruses are pathogens.
Pathogen
There are two types of immune defense.
• Nonspecific Responses
• Specific Responses
Nonspecific Responses
• Nonspecific responses do not discriminate
between specific pathogens. It kills
whatever it can.
• Nonspecific responses can be chemical or
physical.
The First Line of Defense
• The first line of defense that your body has is your
skin, mucus, sweat, and tears.
• Of the four that are listed above the skin is the most
important it acts as an almost impenetrable barrier
between your insides and the rest of the world.
• The mucus, sweat, and tears can produce enzymes
that attack bacterial cell walls.
• The oil/sweat glands in your skin can create an acidic
environment that kills bacteria.
• The mucus traps pathogens, which are then swept
back up the throat by cilia.
• The stomach acid dissolves the pathogens that make it
to the stomach.
The Second Line of Defense
• Inflammatory Response
• If bacteria get in they release toxins into your blood.
This triggers the release of millions of macrophages,
which will try to “eat” the bacteria.
• Your immune system will also release chemicals to
increase your core temperature. This gives you a fever.
• Fevers can be both good and bad for your body.
• Many pathogens can only live in a limited range of
temperatures, so often a fever will kill them.
• The fever also causes your heart to pump blood faster which
spreads the macrophages around your body more quickly.
• Your body can only run on a limited range of temperatures, if
your body’s temperature reaches too high (108F) you die.
Inflammatory Response
Inflammatory Response
Interferons
• Infected cells make proteins called interferons
to slow viral growth and send it to other cells.
• This gives the other cells, and your immune
system time to prepare.
Specific Defenses (Immune System)
Third Line of Defense
• The immune response’s job is to attack,
destroy, and remember pathogens.
• Your specific immunity is triggered by, and
remembers, antigens.
• Antigens are unique proteins found on each
pathogen that signals to the immune system that
they are nonself (not part of your body).
Who are the specific defenses “players”
• White Blood Cells
• Macrophages (Phagocytes)
• B – Cells
• T – Cells
Part 1: Humoral Immunity
• Step 1: Macrophages “eat” a pathogen.
• Step 2: The macrophage displays the antigens to a helper T
cell.
• Step 3: The helper T cell “tells” the B cells to start making
antibodies
• Antibodies are Y shaped proteins produced by B
cells.
• They travel easily in blood
• They bind to pathogens by their antigens and cause
them to clump up, which makes it easier for
macrophages to “eat” them.
• Antibodies have antigen-binding edges, which fit to a
particular antigen like a lock and key.
• The amino acids at those ends can rearrange
themselves to match millions of different antigens.
Antigen
Macrophage (phagocyte)
displays the antigens to the
Helper T.
Helper T tells the B
cells to start making
antibodies, which stop
pathogens in their
tracks!
End of Part 1
• Step 4: Some B cells
“remember” (Memory B Cells)
the antigens of specific
pathogens which make it a lot
easier to kill them later.
• They respond so quickly the
second time around that you may
not even feel sick.
Humoral Immunity
Part 2: Cell Mediated Immunity
• This type of immunity eliminates your cells that
have already been infected by pathogens.
• Step 1: Helper T cells alert the rest of the T cells
• Step 2: The killer T cells destroy infected cells.
• Infected cells have the pathogen’s antigens displayed
on their cell membrane.
• Step 3: The suppressor T cells tell the killer T cells to
stop when there are no more infected cells.
• Step 4: The memory T cells remember the pathogen’s
antigens just like memory B cells.
Cell Mediated Immunity
Go kill any infected
cells, Killer T.
Yes sir!
Immune System Issues, and at a time like
this!
• People who need to have organ transplants have to
suppress their immune system.
• This is because, even if you have a life saving organ
transplant, your body will probably reject the organ.
• The new organ does not have the correct antigens
displayed on their cell membranes, so your body
sees it as nonself.
• To your immune system nonself = BAD!
Active Immunity vs. Passive Immunity
• Active immunity = triggering an immune response
from your body, antibodies must be produced by
plasma cells
• Vaccinations are injections (shots) of a weakened
or mild form of a virus (like practice viruses for
your body) that cause your body to experience an
immune response, natural.
• You’ve had a bunch of vaccinations, artificial:
• MMR = measles, mumps, and rubella (German
measles)
• DPT = Diptheria, pertussis (whooping cough), tetanus
• Tuberculosis
• Polio
• Chicken pox (maybe)
Active Immunity
We’re
on
the
job!
Passive Immunity
• Passive immunity = you are given antibodies
by someone else instead of making your own.
• You may get antibodies, gamma globulin, for
tropical diseases if you are leaving the country,
artificial.
• You also got antibodies from your mother when
she breast fed you, natural.
Passive Immunity
Get your new and improved antibodies today! See your
doctor if you are planning on visiting a tropical country
today. Don’t wait. Supplies are limited.
Legal Notice: This is a one time use only, and will not help your immune system to overcome any diseases in
the future.