Download Something that makes us sick, causes disease

Challenge Problem
Body Defenses: The Immune
System
12c
Let’s Review Pathogens- 8min
Something that makes us sick, causes disease
-Use your phone to find 5 pathogens, quick description and an
example of a disease they cause. If you know one from
memory you can write that down.
1- pathogen example
2345-
ex- disease example
exexexex-
Third Line of Defense:
Immune System
Specific Defense: The Immune
System
 Important Aspects
 Antigen specific
 recognizes and acts against particular
foreign substances
 Systemic
 not restricted to the initial infection site
 Has memory
 recognizes and mounts a stronger attack on
previously encountered pathogens
Types of Immunity
 Humoral immunity
 Antibody-mediated immunity
 Cells produce chemicals for defense
 Cellular immunity
 Cell-mediated immunity
 Cells target virus infected cells
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.25
So, how does the immune
system know which cells to
attack?
Antigens
• Antigen
– Surface Proteins that identify the cell
• Self: found on cells that belong to the
organism
• Non-Self: found on cells that do not
belong to the organism
–invaders
Antigens (Nonself)
 Any substance capable of exciting the
immune system and provoking an immune
response
 Examples of common antigens
 Foreign proteins
 Nucleic acids
 Large carbohydrates
 Some lipids
 Pollen grains
 Microorganisms
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.26
Self-Antigens
 Human cells have many surface
proteins
 Our immune cells do not attack our own
proteins. They only attack “foreign”
proteins.
 Our cells in another person’s body can
trigger an immune response because
they are foreign
 Restricts donors for transplants
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.27
Quick Quiz
• What is an antigen? (in your own words)
• Why are antigens so important in the
immune response?
Let’s review the cells involved
in the immune system
Cells of the Immune System
 Lymphocytes
 Originate from hemocytoblasts in the red bone
marrow
 B lymphocytes become immunocompetent in
the bone marrow
 T lymphocytes become immunocompetent in
the thymus
 Macrophages
 Arise from monocytes
 Become widely distributed in lymphoid organs
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.29
Activation of Lymphocytes
Figure 12.9
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.30
Immune Response:
Humoral Immunity
Involves Antibodies!!
Humoral Immunity
• 1) B-Cells recognize and attach to a
foreign antigen
• 2) B-Cells reproduce
– Plasma Cells: produce Antibodies specific
to attack this antigen
– Memory Cells: for quick attacks on future
encounters with this antigen.
Humoral Immunity
• 3) Antibodies bind to foreign antigens on
cells and disable them
• 4) Macrophages engulf and destroy
cells that have antibodies attached.
Humoral Immune Response
Figure 12.10
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.32
Secondary Response
 Memory cells
are long-lived
 A second
exposure
causes a rapid
response
 The secondary
response is
stronger and
longer lasting
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 12.11
Slide
12.33
Quick Quiz
• Why is humoral immunity also called
“Antibody-mediated Immunity”?
• What type of lymphocyte is involved in
Humoral immunity?
Active Immunity: Permanent
 Your B cells
encounter
antigens and
produce
antibodies
 Active immunity
can be naturally or
artificially acquired
 Get Sick
 Get an
immunization
shot
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 12.12
Slide
12.34
Passive Immunity: Temporary
 Antibodies are obtained from someone
else
 Conferred naturally from a mother to her
fetus
 Conferred artificially from immune serum or
gamma globulin
 Immunological memory does not occur
 Protection provided by “borrowed
antibodies”
Slide
12.35
Antibody Structure (draw it)
 Four amino acid
chains linked by
disulfide bonds
 Two identical
amino acid
chains are linked
to form a heavy
chain
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Figure 12.13b
Slide
12.38a
Antibody Classes
 Antibodies of each class have slightly
different roles
 Five major immunoglobulin classes
 IgM – can fix complement
 IgA – found mainly in mucus
 IgD – important in activation of B cell
 IgG – can cross the placental barrier
 IgE – involved in allergies
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.39
Antibody Function
 Antibodies inactivate antigens in a
number of ways
 Complement fixation
 Neutralization
 Agglutination
 Precipitation
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide
12.40
Quick Quiz
• Name two ways to get “Active Immunity”
• How can you get “Passive Immunity”?
• What is the primary difference between
active and passive immunity?
Antibody Act-ivity
• Read the ½ sheet of paper and be prepared
to get a part
• After a demo, you will be moving around the
room like bacteria, antibodies, B-cells, and
macrophages!!
Assignment
• Create a 6-frame comic strip that
outlines the humoral immune response
steps.
– Must have colored pictures
– Must clearly explain each step of the
response.
– Be creative!!