Immune systems Flashcards
Immune System overall goal
defends body against pathogens (foreign invaders).
Innate Immunity:
NONSPECIFIC immunity that responds the
SAME way to any type of pathogen, whether or
not it has been encountered previously.
goal to keep pathogens out and prevent them from entering the bloodstream
Barrier defenses:
provide a physical barrier
& secretions to keep pathogens OUT.
Cellular innate defenses:
fight pathogens that get through the skin.
Includes:
◦ Phagocytic WBCs: recognize pathogens based on surface molecules
unique to that particular group (Ex. bacteria vs. virus)
◦ Engulf pathogens & destroys them!
◦ Present antigens to WBCs so they can mount a specific attack if needed!
◦ Antimicrobial Proteins:
destroy pathogens & recruit phagocytes (WBCs)!
interferons
infected cells spread message to not let in more bacteria, try to help slow the spread of disease
complement system
breaks down cell wall and attracts phagocytes to premot immunity.
inflammatory response
- increases blood flow
- phagocytes activated
- capillary permeability increased
- complement activated
- clotting reaction walls off region
-regional temperature increased - if needed specific defense activated
Antimicrobial Proteins Produced During the Innate Immune Response
-Proteins that inhibit viral replication.
- 30+ proteins that enhance immune
response. - Triggered by tissue damage & leads to
release of chemical signals.
Adaptive
(Acquired)
Immunity:
WBCs respond to
pathogens based on their
specifically shaped antigens.
Antigens:
specifically shaped proteins on the surface of pathogens that trigger an
immune response!
How? WBCs have specific RECEPTORS that recognize antigen shapes!
How do antibodies work?
- Neutralize pathogens by blocking parts of
pathogens necessary for invasion & survival. - Antibodies bind to antigens & “tag”
pathogens/infected cells for attack by WBCs. - Activates complement system proteins that
bind to & lyse pathogens!
Immune System:
defends body against pathogens (foreign invaders).
Innate Immunity:
NONSPECIFIC immunity that responds the
SAME way to any type of pathogen, whether or
not it has been encountered previously.
Goal? Keep pathogens OUT or prevent them from
entering the bloodstream.
Barrier defenses:
provide a physical barrier
& secretions to keep pathogens OUT.
Cellular innate defenses:
fight pathogens that get through the skin.
Includes:
◦ Phagocytic WBCs: recognize pathogens based on surface molecules
unique to that particular group (Ex. bacteria vs. virus)
◦ Engulf pathogens & destroys them!
◦ Present antigens to WBCs so they can mount a specific attack if needed!
Antimicrobial Proteins:
destroy pathogens & recruit phagocytes (WBCs)!
Antimicrobial Proteins Produced During the Innate Immune Response
-Proteins that inhibit viral replication.
-30+ proteins that enhance immune
response.
-Triggered by tissue damage & leads to
release of chemical signals.
interferons
increase resistance of cells to infection, infected cells tell healthy cells to not let pathogens in order to not get infected.
complement system
attacks and breaks down cell wall attracts phagocytes and creates inflammation
inflammatory response
- blood flow increased
- phagocytes activated
-capillary permeability increased - complement activated
-clotting reaction walls off region - regional temperature increased
- specific defense activated if needed
Adaptive
(Acquired)
Immunity
WBCs respond to
pathogens based on their
specifically shaped antigens.
Antigens:
specifically shaped proteins on the surface of pathogens that trigger an
immune response!
How? WBCs have specific RECEPTORS that recognize antigen shapes!
Antibodies:
proteins secreted by B cells (WBCs)
into the blood during an immune
response.
◦ Have a complementary shape to the
invading antigen!
How do antibodies work?
- Neutralize pathogens by blocking parts of
pathogens necessary for invasion & survival. - Antibodies bind to antigens & “tag”
pathogens/infected cells for attack by WBCs. - Activates complement system proteins that
bind to & lyse pathogens!
Helper T Cells:
once activated by an Antigen Presenting Cell
(APC), they secrete chemical signals (called cytokines) that trigger
BOTH plasma B cells & cytotoxic T cells to join the immune
response!
Cytotoxic (Killer) T Cells:
attack “infected” body cells.
Plasma B Cells:
make specific antibodies matching the invading antigen shape!
Process?
◦Plasma B cells w/ specific receptors bind to complementary shaped antigens.
◦Once activated by Helper T Cell cytokines, plasma B cells secrete antibodies into
the blood.
Memory B Cells:
Cells: memorize antigen shape & trigger an IMMEDIATE immune
response if the same antigen invades a 2nd time.
Primary Immune Response
◦Occurs when body is 1st exposed to
a NEW antigen shape & WBCs are
activated!
Secondary Immune Response
◦Occurs when the SAME antigen shape is
encountered @ a later time.
◦ Faster response of a greater magnitude!
◦ Memory B cells rapidly activate & MORE
specific antibodies are immediately made.
Vaccination:
injection of a weakened/deactivated pathogen w/antigens!
◦ Stimulates an Adaptive Immune Response to the specifically shaped antigens.
◦ Primary Immune Response occurs 🡪 creation of specific B & T Cells, antibodies, etc.
◦ So…exposure to the REAL, harmful pathogen w/ same shaped antigens is reacted to as a
Secondary Immune Response 🡪 faster @ a greater magnitude!
Allergies
:
misguided reaction to antigens found on
substances (allergens) that are ordinarily
harmless.
Organ Transplants
:
antigens on transplanted
cells are seen as foreign &
trigger an immune
response in the recipient’s
body! ◦Donated organ is
attacked & begins to fail.
Pathogens:
infectious agent that causes disease (has specific antigens on its surface). bacteria, fungi, virusis, protazo
Viruses:
abiotic particles that must infect a living cell in order to replicate/reproduce.
Human Immunodeficiency Virus (HIV):
infects & attacks Helper T
cells (also called CD4 cells).
◦Helper T cells cannot
stimulate plasma B cells or
cytotoxic T cells.
◦Immune system weakens,
WBC count decreases,
antibodies aren’t made as fast 🡪
leads to AIDS.
SARS-CoV-2
strain of coronavirus not previously
identified in humans until 2019.
◦Unique/NEW antigen shape was
not been encountered until
recently, leading to a pandemic.
