Download Lymphatic System Notes (2 of 3)

Essentials of Human Anatomy & Physiology
Seventh Edition
Elaine N. Marieb
Chapter 12- ppt 2
3rd line of defense
AKA Immunity
Pgs 389-390
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
3rd Line of Defense- T and B lymphocytes
Review:
•Antigen (Ag)- any substance that causes immune response
(3rd line / “specific” defense)
•Pathogens - viruses, bacteria, fungi, protein-hapten
combo (allergen-pollen) are Ag’s
•AMI (Humoral) – Antibody Mediated Immune Response
carried out primarily by B Cells (and their antibodies) to
attack extracellular pathogens (ex. bateria, fungi, viruses)
•CMI – Cell Mediated Immune Response carried out
primarily by T Cells (and their helpers) to attack
intracellular pathogens (ex. cancer, transplanted tissue)
Slide 12.17a
Activation of Lymphocytes
NOTE: Both T and B Cells
(Lymphocytes) are made in Bone
Marrow!
1. B Cells - stay in bone marrow to
become “immunocompetent”
T Cells - go to Thymus to
become “immunocompetent”
2. Immunocompetent (but still
Naïve) B & T Cells Travel to
Lymph Nodes & other Lymphoid
Tissues to face their “Antigen
Challenge” in which they become
Mature (Activated)
3. Mature B and T cells
recirculate through blood & lymph
ready to help you!
Figure 12.9
Slide 12.30
Antibody Mediated Immune Response
(AMI) – aka “Humoral”
•
AMI (“humoral”)
1. Extracellular Antigen (Ag) (ex. bacteria, extracellular viruses)
is detected and MHC1 is presented by antigen presenting cell
This leads to…
2. B lymphocytes (B cells) and their antibodies (Ab’s) attack the extracellular
Antigens (Ags) by producing:
1.
Plasma Cells
2.
Antibodies
3.
Complement
Slide 12.17a
Cell Mediated Immune Response (CMI)
•
CMI (cell mediated)
1. Phagocytosis of antigen (by macrophage)
2. Macrophage presents MHC2
Which lead to…
3. Helper T Cells (type of T cell) to trigger Cytotoxic T Cells to
release their chemicals to attack intracellular Ag’s (ex. cancer,
viral infected cells & transplanted tissue):
Those Chemicals Include:
•
Lymphokines
•
Lymphotoxins
•
Interferon
Slide 12.17a
FYI ONLY
•Remember…..If 1st line of defense fails, it
leads to 2nd line, if 2nd line fails, it leads to
3rd line
•In lymph nodes are T and B lymphocytes
(cortex) and macrophages and other
phagocytes (medulla)
•Lymph nodes filter lymph and the
macrophages/“phagocytes” are called
antigen presenting cells (APC).
•Phagocytosis (2nd line of defense)
activates T and B cells (3rd line) which
function in the cortex of lymph nodes
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.30
Antigen Determines Pathway!!
Intracellular = CMI
or
Extracellular = AMI
CMI
IL-2
IL-1
AMI
Figure 12.15
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.43
Macrophages (APC) DIRECT AMI or CMI:
• IL-1 (Interleukin 1) - secreted by macrophages and
Helper T cells to stimulate B cells (AMI) Antibody
Mediated Immunity
(Plasma Cells, Antibodies, complement, B memory Cells)
• T Helper cells - circulate and recruit other cells to
fight invaders; called the “directors”
• IL-2 (Interleukin 2) - released by Helper T cells
which stimulate cytotoxic T cells
• Cytotoxic T cells - (CMI) Carry out Cell Mediated
Immunity by making chemicals (below) when activated
(Interferon, Lymphokines, Lymphotoxins, T memory cells )
Warm-Up (like a pyrogen )
On the chart, put the following descriptors into the correct
category (either AMI or CMI or BOTH):
B Cell Directed
APC presents MHC2
Intracellular antigens
T Cell Directed
Helper T Cells involved
APC presents MHC1
Extracellular antigens
Uses Cytotoxic T Cells
Stimulated by IL-1
APC involved
CMI
AMI
Both
Primary (first encounter) Vs
Secondary Exposure (memory)
(MHC2)
( w/ IL-2)
Slide 12.17a
Summary of Possible Immune Responses
CMI
AMI
extracellular
w/ MHC 1
w/ MHC 2
intracellular
IL-1
Growth factor
inhibits
IL-2
Ts cell
inhibits
Antigen (2nd exposure)
lymphokines
lymphotoxin
**interferon
**complement
Figure 12.16
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.45
CMI Immune Response
macrophage
(MHC2)
Interferon,
lymphotoxins
,
lymphokines
produced
Cytotoxic
T Cells
Slide 12.17a
Summary of CMI
CMI
AMI
1. Antigen encounter
2. Macrophage presents MHC 2 to
extracellular
w/ MHC 1
Helper T cells which secrete IL-2
w/ MHC 2
intracellular
Il-1
3. IL-2 stimulates Cytotoxic
T cells (killer T cells)Il-2
Growth factor
inhibits
4. Cytotoxic T cells Produce/stimulates
T cell
inhibits
lymphokines, lymphotoxins and interferons
(Some cytotoxic T cells alsoAntigen
produce
T
(2nd exposure)
memory cells
s
lymphotoxin
lymphokines
**interferon
**complement
Figure 12.16
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.45
Interferons, Lymphokines & Lymphotoxins
Interferons
•Made by infected cells as a
“warning”!
•Prevents viruses from
infecting new healthy cells!
Lymphokines
Lymphotoxins
• Stimulate additional
Cytoxic T cells
• Attract other WBC
(produce more IL1 &
IL2
• Enhance macrophages
•Protein produced by T-cells
and induces phagocytic cells
to bind to invaders
AMI Immune Response PREVIEW
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.32
1. Antigen encounter
Summary of AMI
2. APCCMI
secretes IL1 or
presents MHC 1
AMI
3. Stimulates B cells
to differentiate
into Plasma
extracellular
w/ MHC 1
w/ MHC 2
intracellular
cells (which produces
Il-1
antibodies) which
Growth factor
Il-2
activate:
• Phagocytosis
inhibits
T cell
inhibits
• Complement
• Lysis
Antigen (2nd exposure)
• chemotaxislymphokines
s
**complement
Figure 12.16
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
**interferon
Note: Some B cells also
differentiate into
memory B cells
lymphotoxin
Slide 12.45
AMI: Antibody Mediated or Humoral
Immunity (in Detail)
• Extracellular Ag is detected by an APC (macrophage
or Helper T cell)
• B cells are activated
• B cells differentiate into Memory B Cells or Plasma
cells
• Plasma Cells- synthesize Antibodies (Ig)
• Antibodies - agglutinate (sticks to) with the antigen &
activates:
» Phagocytosis
» Complement (inflammatory response and opsonization)
» Lysis
» Chemotaxis (& its resulting inflammation)
Activation of Complement
Made in 3rd line
Acts in 2nd line
Figure 12.14
inflammation
Slide 12.41
Antibodies or Immunoglobulins: (Ab
or Ig’s)
• Antibodies (Ab’s) are
proteins secreted by
plasma cells (made from B Cells)
 Circulates in blood plasma
 Ab’s bind to a specific
antigen (Ag)
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.37
Antibody (Ig) Structure
Figure 12.13b
4 polypeptide chains (attached by
disulfide bonds):
•2 heavy
•2 light
•Variable region specific for Ag
•Constant region determines type
of Ig
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.38a
5 Types of Antibody (Ig) Classes
M.A.D.G.E.
IgM
IgA
IgD
IgG
IgE
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Types of Ig’s
• Five major Ig classes:
 IgM – fixes complement
Agglutination agent;
pentamer
 IgA – in mucus membranes and their
secretions, ex. milk, saliva, tears, etc.
Monomer and dimer; prevents
pathogen from entering body
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.39
Types of Ig’s
• Five major Ig classes
 IgD – on B cells, activates other B cells
 IgG – crosses the placenta during pregnancy, fix
complement. Most abundant
monomers
 IgE – leads to allergies
In skin, mucosae of resp tract,
intestines, and tonsils
Binds to mast cells & basophils &
triggers the release of histamines
and other chemicals that mediate
inflammation
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.39
Monoclonal Antibodies
 Isolate one single B cell line that
produces one kind of Ab
 Clone the Ab in a lab
 Examples of uses:
 Pregnancy tests
 Treatment for hepatitis, cancer, rabies
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.36
Primary and Secondary Responses
Primary response
and Memory Cells
(1st exposure) causes
Memory cells
Gradual rise &
rapid decline
Rapid rise &
remains high
for some time
illness AND memory
cells made
Secondary response
is quicker for future
exposures because
memory cells are
made during the
primary response
Figure 12.11
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.33
Vaccines
Active Artificially
Acquired Immunity
Vaccination is a preventative shot
that contains weakened or dead
viruses that cause a primary response
WITHOUT illness and memory cells
are made protect against future
exposures for secondary response
Slide 12.33
Antibiotics
Medicine given to kill bacterial infection, cannot be used for viral
infections
Must take it for full 7-10 days otherwise, bacterial infection can
come back and/or can cause antibiotic resistance in bacteria
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.33
Antibiotic resistance
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.33
Why we get sick…why the symptoms
The Ag’s attack and
kill our cells
We attack the Ag’s with our immune responses
ex fever, inflammation, etc
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.34
Antiserum
Animal’s Ab’s produced
against an Ag that can be
given to a human to protect
it against same Ag
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
Slide 12.34
Types of
Immunity
Active – body
makes memory
as a result of an
antigen
challenge!
Passive - B Cells
are not
challenged so no
immunological
memory…but
you are “cured”
for the time being
Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings
animal’s Ab’s
(antiserum)
Figure 12.12
Slide 12.34