Download Chap 40 Immune Syst

Chapter 40
Immune System
Mr. Karns
Biology
Color Coding
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•
•
•
Red – most important
Orange – next most important
Yellow – it is o.k. to write it down
White – you likely do not need to write it down
• Taking notes is about deciding what is important
and deciding if you can look it up later or not
Infectious diseases
• Pathogenic (disease-causing)
• Methods of transmission
– Airborne droplets: chicken pox, flu, influenza
– Direct contact: cold sores, Hepatitis B, C
Exchange of bodily fluids: STD’s –
HIV/AIDS, syphillis, gonorrhea
– Objects Contaminated H2O: polio, cholera
Contaminated food: botulism, E. coli (some
strains only)
– Vectors: Lyme disease (ticks), malaria (mosquitoes),
bubonic plague (fleas)
SNEEZE VIDEO
• Just Watch and Enjoy 
Determining
cause of a
disease
Koch’s
Postulates
SCIENTIFIC METHOD - Koch’s Postulates
1.
2.
3.
4.
Identify pathogen every time
Isolate & grow
Infect healthy organism
Isolate from new host
(and grow it again if you need to)
• [Note: This method doesn’t work with syphilis
organisms nor viruses.]
• (Viruses can’t be grown outside of a living cell,
so #2 above won’t work)
Reservoirs of infectious organisms
• Human beings
•
Carriers: people who contain pathogens and
pass them on to others before any symptoms
show in themselves.
• Incubation period = time during which organisms are
multiplying and before any symptoms show up.
• Animals
– Birds, insects, mammals
• Soil
– Botulism and tetanus bacteria, anthrax
(or in poorly processed canned food)
What do pathogens do to cause disease?
• Bacteria produce toxins
– Cause fever, inhibit protein production,
destroy RBCs and blood vessels, cause spasms
(by disrupting nervous system impulses)
• Ex. tetanus toxin: causes uncontrolled muscle
contractions -- eventually paralysis and death
• Viruses multiply in cells, lyse (burst) some
cells as they multiply and thereby injure
tissues.
Spread of disease
know these three terms
• Endemic disease: low-level of infection
which is constantly present in a population
• Epidemic: a localized outbreak of a disease
– Polio outbreak during 1950s
• Pandemic: world-wide outbreak of a
disease
– Influenza of the early 1900s
How to treat infections
• Antibiotic: chemical substance produced by
a microorganism which can inhibit the
growth and reproduction of other
microorganisms.
– Produced by many bacteria and fungi, sponges
– Work on gram positive bacteria
– Cause the cell wall to breakdown (lysis)
• Nothing good available to inhibit viruses
(AZT is a reverse transcriptase inhibitor
used to treat HIV infections with AIDS)
A Potential Problem
• The overuse of antibiotics kills off all the
sensitive pathogens -- only the mutant
resistant pathogens remain to repopulate.
– Penicillin-resistant syphillis organisms (produce
penicillinase)
– Drug-resistant strains of tuberculosis
bacteria already exist
Non-Specific Immunity
1. Skin
2. Inflammation
3. Phagocytosis (Innate Immunity)
a. Macrophages (1st line phagocytic defense)
b. Neutrophils (2nd line of phagocytic defense)
c. Monocytes (3rd line of phagocytic defense)
Nonspecific immunity
• Innate immunity: “inborn” immunity
– 1. Skin
• Physical barrier
• Secretions (skin, nose, lungs, etc.)
–
–
–
–
–
Mucus
Sweat (some enzyme lysozyme)
Tears (much enzyme lysozyme) (Alexander Flemming discovered)
Saliva (some enzyme lysozyme)
Gastric juice (HCl and other chemicals kill lots of bacteria)
the skin has a pH between 3 and 5, which is acidic
enough to prevent colonization of many microbes
• 2. Inflammation process
– Caused by Histamine release!
– a. Reddening of area because blood vessels dilate
– b. Swelling
c. Pain
d. Heat
Phagocytes
• Phagocytes are white blood cells that
ingest and destroy pathogens.
• What are the three phagocytes?
Phagocytosis is
– the process by which phagocytes ingest and
destroy pathogens
• 3. Some White blood cells are phagocytes
(“eating” cells)
– Tissue macrophages (“big eaters”)
– Neutrophils (WBC) can phagocytose bacteria
– Monocytes (large WBC which become macrophages)
– Macrophages and neutrophils die after “eating” pathogens;
along with dead tissue cells and plasma, they make pus!
Phagocytosis Video
Puncture Wound Video
Be prepared to draw a diagram of the process!
Lymphatic system
•
•
•
•
Lymph capillaries
Lymph vessels
Lymph Nodes
Thymus
– T cells mature
• Spleen
– Storage of WBC
& RBC
• Tonsils
Purpose of Lymph System
• Return tissue fluid (previously blood
plasma) back to heart and into circulation
• Tissue fluid is called lymph once it enters
lymphatic vessels
General arrangement of capillaries
and lymphatic vessels (green)
Lymph nodes
• Contain lymphocytes
(WBCs) which...
– Defend body against foreign
substances
• Filter lymph of most
bacteria
White Blood Cells = Leukocytes
• Phagocytes:
– Macrophage
– Neutrophil
– Monocytes
• Lymphocytes
– T cells (Helper, Cytotoxic and Memory T-cells)
• Mature in the thymus
– B cells (Memory B cells and plasma cells)
RED and WHITE blood cells are produced in bone marrow
Specific Immunity
• Acquired Immunity
– Passive
– Active
• Antibody Immunity (Humoral Immunity)
• Cellular Immunity (for viruses, cancer cells,
tumors)
Antibodies react with antigens
and do several things
Antibody (humoral) Immunity
Be prepared to draw the process of humoral immunity.
.Helper T cells are important !
.Cytotoxic T cells are Killer T cells
Steps of Antibody Immunity
Displayed
antigens
Cellular Immunity for Viral Defense
Be prepared to draw the process of cellular immunity
Draw a diagram of the cellular
immune response.
You may work in groups of three,
but everyone needs to draw the
diagram.
Cellular Immunity
Lesion = opening
Perforin = cluster of
proteins which make a
Lesion (hole).
(Cytotoxic = Killer)
Interferon Proteins
– Produced by virus-infected cells
– Interferons are host-specific (human proteins
only work for humans, etc.)
– Interferon act as an “alarm” molecule to
uninfected cells
– Uninfected cells produce antiviral proteins
which prevent viruses from entering them.
[Summary note: cells of innate (nonspecific) immune
system constantly monitor tissues for foreign
invaders and attempt to suppress the “invasion”.]
Allergy (can be specific or
non-specific)
• Is an exaggerated
reaction to antigens
• A 2nd exposure to an
environmental Ag
causes the typical
allergic reaction
– Histamines affect
tissues throughout
whole body similar to
an inflammatory
reaction.
(pollen grain)
• 1983: HIV -- is a retrovirus (RNA virus;
contains reverse transcriptase to reproduce
itself in a host cell)
• HIV infects and kills helper T cells
• Nearly all HIV carriers will have AIDS and will
die from cancers or opportunistic infections.
HIV structure
and infection
of helper T cell
HIV / AIDS / Immune System
• 1981: rare types of pneumonia and skin cancer
(Karposi’s sarcoma) noticed in San Francisco
– Nonfunctioning immune systems in patients
Purple splotches common in Karposi’s sarcoma
HIV budding from helper T cell
HIV
End
It’s time for TEST Review
1. A general type of “eating” cell is
phagocyte
called a __________
.
2. A specialized type of big “eating”
cell in the immune sytesm is called
a ________
macrophage and is usually considered
to be part of nonspecific immunity.
3. AIDS is a disease of the immune system
because HIV infects and kills the
___________
cells which are important
Helper T
in developing an immune response.
4. Organ transplants procedures require
the patient’s immune system to be
suppressed before the procedure begins?
Why?
To prevent cellular immunity methods
from rejecting the donated organ.
Easy
questions
Question 1
Diseases that are constantly present in the
population are called _____
A. endemic diseases
B. epidemic diseases
C. immunity diseases
D. resistant diseases
Question 2
Who first proved that a specific microbe
caused a particular disease?
A. Jenner
B. Mendel
C. Darwin
D. Koch
Question 3
While in the lymphatic vessels, tissue fluid
passes through structures called _____
that filter the fluid.
A. lymphocytes
B. lymph nodes
C. thymus glands
D. mucus traps
Question 4
Which of the following are part of the
nonspecific defense (innate immune
system) against diseases?
A. B cells
B. T cells
C. plasma cells
D. macrophages
Question 5
Which cells are attacked by HIV?
A. B cells
B. T cells
C. plasma cells
D. macrophages
Medium Difficulty
questions
Question 1
A baby is born lacking a thymus gland.
What cells are missing in the child?
A. B cells
B. T cells
C. plasma cells
D. macrophages
Question 2
What is the relationship between tissue fluid and lymph?
A. Tissue fluid leaks out of blood vessels and is
called lymph when it enters lymphatic vessels.
B. Tissue fluid surrounds the body cells, and lymph
circulates throughout the body in the lymphatic
system.
C. Lymph leaks out of the blood. It is then
called tissue fluid.
D. Tissue fluid is the liquid portion of the blood. When
it leaks out of the capillaries, it is called lymph.
Question 3
What is the function of a booster shot?
A. Some individuals are allergic to the first
shot, so they need more than one
shot.
B. The booster vaccines contain different
materials.
C. When the body is re-exposed to a
disease agent, it forms more memory
cells for immunity.
D. A booster shot will activate different
cells of the immune system from
those activated by the first vaccine.
Question 4
Why do patients with AIDS continually battle
infectious diseases?
A. AIDS patients are infected with the
HIV virus.
B. AIDS causes the production of
interferon.
C. AIDS destroys the plasma cell response
to infectious diseases.
D. AIDS weakens a patient's immune
response to infectious diseases.
Question 5
Why does a vaccination give long-lasting
protection against a disease?
A. Vaccines increase the level of
antibodies in the bloodstream.
B. Vaccines contain dead or weakened
disease agents.
C. Vaccines prevent the body from
responding to disease agents.
D. Vaccines cause the body to create
memory cells that are prepared to fight any
future encounters with the disease organism.
Difficult
questions
Question 1 (analogy)
Virus-infected cells are to interferon as
plasma cells are to _____
A. complement
B. lysozyme
C. antibody
D. helper T cells
Question 2
When a patient receives a kidney transplant, the patient's
immune system is suppressed by the use of prescribed
drugs. Why would this be important and necessary?
A. Without this suppression, the immune system
would attack the foreign transplanted tissue.
B. The suppression will stimulate the immune
system to work more efficiently.
C. The suppression will stimulate the bone
marrow to produce more white blood cells.
D. Without the suppression, the body will
secrete too many hormones.
Question 3
Why might a physician recommend against taking
a fever-reducing medication when you have an
abnormally high temperature?
A. A high temperature activates the
immune system.
B. A high temperature inhibits the growth
of some disease-causing bacteria.
C. A high temperature decreases blood
flow, so the disease will spread more
slowly.
D. A high temperature inhibits the body's
repair.
That’s all . . .
Do well on your test :)
A bit of a review and some
detail follows.
Watch carefully I will
move quickly.
Cellular immunity, cancer, & organ transplants
• Cytotoxic (Tc) cells will “lock onto” any cell which
presents a “foreign” molecule
– Virus-infected cells present an Ag in the midst of
their own self marker molecules (new markers are
made continuously)
– Malignant cancer cells present unusual molecules which
attract Tc cells; Tc usually keep cancer cells “in check”
• Some types of cancer lose their ability to continue making self
marker molecules and don’t present the unusual molecules
which ordinarily attract Tc cells.
– Transplanted organs may contain slightly different self
markers and attract Tc cells
• Immunosuppressant drugs such as cyclosporin A are used
before, during, and after the transplant procedure to avoid
activation of helper T cells.
Acquired immune response
• Self components of a person’s own body
– Self marker is a cluster of proteins on plasma
membrane surface; cluster is a “protein fingerprint” -unique for each person (real term = major histocompatiblity complex)
• Foreign substances are nonself.
– Nonself molecules are called antigens
• Pollens, dust particles, animal dander, bacteria, viral proteins,
etc.
• Acquired immune response is a process of producing
specific antibodies against specific antigens
• Acquiring immunity takes time (up to 2 weeks)
Thymus gland
• Immature
lymphocytes
mature into T cells
• Gland declines in
size by adolescence
The Spleen
• Contains
lymphocytes
• Filters and
destroys bacteria
• Removes old RBCs
from circulation;
liver converts them
into bile
Antigen-Antibody binding is specific
Two kinds of acquired immunity
• Antibody (humoral) immunity
– Antibodies circulate in the blood (humor)
• Cellular immunity
– Antibodies remain attached to immune cells
(lymphocytes)
– Acquired immunity is SPECIFIC and occurs
simultaneously with Innate or non-specific
immunity.
• Lymphocyte: basic cell of immune system
– Made in red bone marrow from stem cells
B T
Specific immunity
• Occurs simultaneously with innate immune cells
• Certain white blood cells (lymphocytes) “learn” to
recognize foreign substances and react
specifically to them.
– These cells can eventually inactivate/destroy
pathogens
– This takes time (from days up to 2 weeks).
• Immunity which results is called
acquired immunity.
– Two categories of lymphocytes
• B cells -- have only been exposed to bone marrow
• T cells -- spend time in and mature in thymus gland;
receive additional attributes beyond B cells
– May circulate in the blood or reside in
lymphoid tissues/organs
• T cells
– Helper T cells interacts with Antigen-presenting macrophages
or Antigen-presenting B cells
a. Macrophage with ingested pathogen,
b. In a food vacuole,
c. Presenting pathogen
M
d. Helper T cell binds to macrophage self
markers; T cells become stimulated by
binding to the antigens on macrophages
T
e. Activated T cells bind to B cells;
f. B cells divide rapidly into plasma cells
and memory cells
Y
Y
YY
Plasma cells
Y
Y
Y
Y
Y
Y
Y
Antibodies Yin blood and tissue
fluid
Y
Y
B
Y
B
Memory B Cells Clone
Y
T
B cells can bind antigens directly
Helper T cell releases chemical
(interleukin) which activates B cell to
divide.
Y
Y
Y
Y
Y
Y
Y
Y
Plasma cells
Y
YY
Y
Y
T
Y
B
Y
Y Y
Y
Y
Y
Memory B Cells Clone
From nonspecific defense to
production of antibodies
Summary
Many B cells
to select from
Only one kind of
B cell becomes
activated by a
specific antigen
Most memory cells
last our whole life.
Primary/Secondary Responses
The complement cascade
• Complement = about 20 proteins in blood
– Complement proteins self-assemble to make a
lesion in plasma membrane; cell lyses
Examples of perforin lesions
Cancer cells
Two types of acquired immunity
• 1. Passive: receive antibodies from
another source -- person, animal, geneticallyengineered antibodies from bacteria
– Ex. Antibodies from mother -- through the placenta;
through breast milk
– Ex. Injection of pooled serum (from many donors) and
its diversity of antibodies from donors.
• 2. Active: antibodies obtained naturally by
having an infection of a pathogen OR
– Receiving a Vaccine of . . .
• Dead or weakened pathogens (viruses, bacteria)
• Edward Jenner (1798): use cowpox virus to
vaccinate against smallpox -- cowpox protein shapes
are similar enough to smallpox to give immunity
• Which type of immunity is longer-lasting -passive or active?