Download 31.3 Immune Responses

31.3 Immune Responses
KEY CONCEPT
The immune system has many responses
to pathogens and foreign cells.
31.3 Immune Responses
• The job of the immune systems is to fight off
pathogens & infections.
– Skin is a physical barrier to infection.
– Mucous Membranes trap pathogens entering
the body.
31.3 Immune Responses
Two nonspecific responses.
1. Inflammation - blood
vessels become leaky.
• characterized by swelling,
redness, and pain
2. Fever - body temperature
increases
• Low fevers stimulate white
blood cells to mature.
31.3 Immune Responses
Cells of the immune system produce
SPECIFIC RESPONSES
• Specific Immune response:
– Antigens are surface
proteins on pathogens.
– Each pathogen has a
different antigen.
antigens
31.3 Immune Responses
White Blood Cells attack
infections inside the body.
1. Phagocytes engulf and
destroy pathogens.
2. T cells destroy infected
cells.
3. B cells produce
antibodies.
- Antibodies make
pathogens ineffective.
31.3 Immune Responses
There are 2 specific immune responses.
pathogen
antigens
1. Cellular Immunity
T-cells to destroy
infected body cells.
antigens
T cell
receptors
memory T cells
activated T cells
31.3 Immune Responses
31.3 Immune Responses
2. Antibody Immunity
B-cells produce antibodies.
B cell
pathogen
antibodies
T cell
memory B cells
activated B cells
31.3 Immune Responses
Both responses produce memory cells
31.3 Immune Responses
• Vaccines
– Allow person to acquire immunity without
contracting disease
– Contain the antigen of a weakened
pathogen
– Does not cure a person who is sick
31.3 Immune Responses
• Vaccination provides immunity.
– stimulates a specific
immune response
– causes memory B & T
cells to be produced
– allows immune system
to respond quickly to
infection next time
– has such a fast
response, a person
will not get sick
Antigens in a vaccine
trigger an immune response,
and memory B cells are
made.
1
memory B cells
2
3
A memory B cell is
stimulated when the real
pathogen binds to it.
The B cell quickly activates
and makes antibodies that
fight the pathogens before
you get sick.