Download Immunology

Chapter 43
The Immune System
PowerPoint Lectures for
Biology, Seventh Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero
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Videos
• Stress, Emotions, and Our Health
• NOVA PBS: Immunity Explained
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Assignment
• Friday – Independent Notes on Chapter 43
– YOU NEED TO READ THE CHAPTER!!!
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Let’s Get Defensive!
Agenda:
Natural Born Killer
Review Notes on Defense
Counting Blood Cells (Activity)
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Let’s Get Defensive!
Agenda:
Natural Born Killer
Review Notes on Defense
Counting Blood Cells (Activity)
What’s snot fun about biology? (Activity)
Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
The Lymphatic System
–
Plays an active role in
defending the body
from pathogens
–
Network of tissues and
organs that help rid the
body of toxins, waste
and other unwanted
materials.
–
Transport lymph, a
fluid containing WBCs
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Copyright © 2005 Pearson Education, Inc. publishing as Benjamin Cummings
Innate Immunity
1. First line defense?
2. Second line of defense?
3. How does the first line of defense use
chemical barriers?
4. Hepatitis A and the Stomach
10m
3m
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5. Four types of phagocytic WBCs
What are they?
6. How do phagocytic WBCs work? What is the
enzyme involved?
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7. Interferons
• Another set of proteins that provide innate
defense against….
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8. The Inflammatory Response
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Adaptive or Acquired Immunity
• Specific defense
• Works WITH innate immunity
• As cells phagocytize microbes, release
cytokines to activate other lymphocytes and
cells of the immune system
9. Antigen?
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Acquired Immunity
• An antigen is any foreign molecule
– That is specifically recognized by lymphocytes
and elicits a response from them
• A lymphocyte actually recognizes and binds
– To just a small, accessible portion of the antigen
called an epitope
Antigenbinding
sites
Antibody A
Antigen
Antibody B
Antibody C
Figure 43.7
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Epitopes
(antigenic
determinants)
Acquired Immunity:
– The humoral immune response: involves the
activation and clonal selection of B cells,
resulting in the production of antibodies or
immunoglobulins (IG)
– The cell-mediated immune response:
involves the activation and clonal selection of
cytotoxic T cells – target cells like cancer
Both receive help by helper T cells
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B and T cells recognize antigens.
-1 million diff. B
-10 million diff. T
A lymphocyte recognizes antigen…
Stimulates and differentiate
-One clone short-lived fighters
-Other clone memory cells
-First time: 10-17 days
-Second time: 2-7 days
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Antibodies
• The five classes
of
immunoglobulins
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The role of helper T cells in acquired immunity
1 After a dendritic cell engulfs and degrades a bacterium, it displays
bacterial antigen fragments . A specific helper T cell binds
to the displayed complex. This interaction promotes secretion of cytokines by the dendritic cell.
Cytotoxic T cell
Peptide antigen
Dendritic
cell
Class II MHC
molecule
Bacterium
Helper T cell
Cell-mediated
immunity
(attack on
infected cells)
TCR
2
3
1 CD4
Dendritic
cell
Cytokines
2
B cell
3 The cells in this clone
secrete other cytokines
that help activate B cells
and cytotoxic T cells.
Figure 43.15
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Humoral
immunity
(secretion of
antibodies by
plasma cells)
THE IMMUNE SYSTEM
EXPLAINED
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Microscope Activity
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Tuesday
• Immune System Problems
• Can You Boost Your Immunity?
• Kahoot
• FRQ and Peer Review
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Organ Transplants and Transfusions
• The immune system can wage war against
cells from other individuals
• Transplanted tissues are usually destroyed
by the recipient’s immune system
– Mismatched antigens
• Use medicine to suppress the immune system
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Allergies
• Allergies are exaggerated (hypersensitive)
responses to certain antigens called allergens
– Perceives harmless substances as dangerous,
body tries to fight them off
– Releases antibodies, IgE, Release Histamine
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• The allergic response
IgE
Allergen
Histamine
1
3
2
Granule
Mast cell
1 IgE antibodies produced in 2 On subsequent exposure to the 3 Degranulation of the cell,
triggered by cross-linking of
response to initial exposure
same allergen, IgE molecules
adjacent IgE molecules,
to an allergen bind to
attached to a mast cell recogreleases histamine and other
receptors or mast cells.
nize and bind the allergen.
chemicals, leading to allergy
symptoms.
Figure 43.20
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Age and the Immune System
• Researchers believe that aging – leads to a
reduction of immune response capability contributes to more infections, more
inflammatory diseases, and more cancer.
• Possible causes:
– Atrophying thymus, reduction in T cells
– Nutrient deficiency
• Less responsive to medications/vaccines
• Can’t recognize self from non-self
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OUTGROWING ALLERGIES
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Autoimmune Diseases
• In individuals with autoimmune diseases
–
The immune system loses tolerance for self and turns
against certain molecules of the body
– Results from hereditary or congenital defects that
prevent proper functioning of innate, humoral, and/or
cell-mediated defenses
Examples:
- Rheumatoid arthritis- damage and
painful inflammation of the cartilage
and bone of joints
- Lupus
- Multiple sclerosis
- Insulin-dependent diabetes (Type 1)
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Figure 43.21
Stress and the Immune System
• Growing evidence shows
– That physical and emotional stress can harm
immunity
• Brain sends stress signals to the endocrine
system
• Releases hormones for fight/flight
• Weakens immune response (Cortisol
suppresses inflammation)
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HIV and AIDs
– Highly susceptible to opportunistic infections
and cancers that take advantage of an immune
system in collapse
– Because AIDS arises from the loss of helper T
cells
• Both humoral and cell-mediated immune
responses are impaired
Figure 43.22
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