The Immune System
History of Disease
• The history of disease:
– 7000 B.C. Ancient civilizations drill holes
in people’s head to release what were
thought to be evil spirits but were really
diseases (Trepanation)
– 460-377 B.C. –Hippocrates (a Greek
physician) hypothesizes that disease is
caused by fluids he called humors
– 1330-1352 – Black death (bubonic
plagues) strikes the world.
• ½ the world’s population dies from it (about
75 million people)
• People burn incense in an attempt to cure it
History of Disease
• The history of disease (continued):
– 1400-1600 Humans begin studying
anatomy
– 1857 – Louis Pasteur hypothesizes that
disease is caused by tiny “animals” (that
is where we get Pasteurized milk)
– 1865 – Joseph Lister – finds that
sterilizing surgical tools reduces
patients’ infections (this is where we get
the name Listerine)
History of Disease
• The history of disease (continued):
– 1883 - Robert Koch makes 4 Postulates
that prove pathogens cause disease
– 1928 – Alexander Fleming discovers
penicillin (the first major antibiotic)
– 1955 – Jonas Salk finds Polio vaccine
– Late ’80’s - Worldwide spread of HIV
(which causes AIDS) especially in 3rd
world countries
– 2002 SARS pops up in China
Basics of Disease
• Basics of disease:
– Pathogen – an agent that causes disease
(pathology – the study of disease)
– Epidemic – rapid outbreak of a disease that
affects many people
– Pandemic – when a disease is common in the
population (like the common cold or flu)
– Germ theory – specific microorganisms cause
diseases
– CDC – Center for Disease Control – based in
Atlanta, Georgia; is responsible for monitoring
diseases and maintaining credible information
for them
Basics of Disease
– Infectious disease – a disease caused by a
foreign organism or agent
– Contagious disease (also called communicable
disease) – a disease that is spread from one
living thing to another
– Vector – anything that carries a pathogen and
transmits it to healthy cells
– Patient zero (or index case) – first known
person to contract a certain disease
– Outbreak – a small localized group of people
or organisms that are infected with a particular
disease
Types of Pathogens
• Types of pathogens:
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–
–
–
–
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Bacteria
Viruses
Fungi
Protozoans
Parasites
Prions
The Immune System
• Types of pathogens:
– Bacteria – small single celled
organisms that make many copies of
themselves in a short amount of time;
they also can release toxins to make
people sick; they can be typically
treated by medicines called antibiotics
– Viruses – nonliving strands of DNA that
are surrounded by protein coats; these
pathogens are harder to treat than
bacteria
Types of Pathogens
– Fungi – single or multicellular
organisms that pierce healthy cells and
steal their nutrients; they usually occur
in warm damp places; can usually be
treated with creams; and example
includes athlete’s foot
Fuzzy Tongue
Types of Pathogens
– Protozoans – single celled organisms
that prey on other cells; one main
example is malaria
– Parasites – organisms that grow and
feed on a host; an example of a
parasite is elephantiasis caused by
filaria which is a microscopic worm
Types of Pathogens
– Prions – small nonliving chains of
amino acids (usually 3-4); responsible
for mad cow disease
Quiz
1-6: List the 6 types of pathogens:
1.
2.
3.
4.
5. 6.
7-8: Most pathogens are either 7. ____ or
8.____ .
9. What is the term that describes a
chemical that can kill most bacterial
infections?
10.Who discovered the first form of this type
of chemical?
Quiz
1. Bacteria
2. Viruses
3. Protozoans
4. Fungi
5. Parasites
6. Prions
7. Viruses
8. Bacteria
9. Antibiotic
10.Alexander Fleming
The Immune System
• Routes of transmission – different
ways that pathogens can get into
the body.
• Routes of transmission include:
–
–
–
–
–
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Body fluids (blood, saliva, semen, etc.)
Bites
Mosquitoes
Open wounds
Direct touch
Eating or drinking something
The Immune System
– Aerosol (that is they are airborne)
– Needles (unsterilized or among drug
users)
– Sexual intercourse
Functions of the Immune System
The immune system functions in:
• Non-specific immunity – trying to
protect the body from all invaders
• Inflammatory response – making
sure that in a non-specific immune
situation more blood flow is sent to
the infected or damaged area
• Specific immunity – the immune
system targets specific pathogens or
toxins
Nonspecific immunity
Nonspecific immunity:
• Includes the skin and the mucous
membranes
• Protects against virtually every type
of pathogen
• Inflammatory response – redness or
heat felt in the infected area
– This is due to increased blood flow
– Increased blood flow means increased
white blood cells
Nonspecific immunity
Nonspecific immunity:
• Fevers – the body can stimulate
production of immune cells and
molecules easier with a higher
temperature
• The body regulates at a higher
temperature (100-102)
• Pyrogens – pathogens that can
mess with the body’s temperature
set point
Specific immunity
Specific immunity:
• Where the immune system will
target specific diseases
• This is usually in the form of
different white blood cells (WBC’s)
and other immune system cells that
circulate in the blood
• Specific immunity is selective
Nonspecific immunity
Types of Specific immunity:
• Passive immunity – immunity to a
certain disease is always in the body
whether the body is infected or not
– Usually can be passed from mother to
child through genetics (DNA) or
through breastmilk
• Active immunity – immunity that the
body produces in response to a
specific infection
Immune System Molecules 0128-08
Antibodies – proteins that have a
specific shape to target and destroy
specific foreign proteins
Antigens – foreign molecules in the
body either from or on a pathogen
Interferons – proteins released by
infected cells to healthy cells to
interfere with a pathogen infecting
the healthy cells
Immune System Cells 01-28-08
White blood cells – cells that travel in
the blood and fight against infections
that have made it into the body
Phagocytes – class of white blood cells
that engulfs and destroys pathogens
Immune System Cells\
Make a chart like this:
Type of WBC
Function
Drawing
Immune System Cells 01-28-08
Types of white blood cells and their
functions:
1. Basophils – Makes chemicals that
cause inflammation in the blood
stream
2. Mast cells – Makes chemicals that
cause inflammation in other body
tissues
Immune System Cells 01-28-08
3. Neutrophil – phagocyte; engulfs
proteins and foreign invaders
4. Macrophage – engulfs dead or dying
body cells and some bacteria;
phagocyte
Immune System Cells
5. Lymphocyte – Destroys infected
body cells or produces proteins that
inactivate pathogens (interferons);
there are 2 types of lymphocytes:
a. T-lymphocytes – destroy body cells
that are infected with pathogens
b. B-lymphocytes – produce proteins that
inactivate pathogens that have not yet
affected a body cell (using interferons)
Immune System Cells
6. Eosinophil – Injects poisonous
packets into parasites and
protozoans
Immunity 01-25-08
Memory cells – specialized T and B
cells that “remember” an antigen
from a pathogen
This allows the T & B cells to destroy
the pathogen a 2nd time before the
body gets sick.
Tissue Rejection
Tissue rejection – when blood or
organs are attacked by the immune
system as a “foreign” invader.
WBC’s have protein markers called
antibodies on their cell’ membrane
Tissue Rejection
These antibodies have a specific
shape.
If an antigen on the surface of a
pathogen or other foreign tissue fits
this antibody, the WBC will
recognize it as foreign and attack it
Tissue Rejection
If you get an organ or blood, you have
to take drugs to weaken your
immune system.
This decreases the chances of tissue
rejection.
This increases the chances of getting
other diseases.
Fighting Disease
Antiseptics – heat or cheimcals used to
kill pathogens outside the body; they
are not specific; they may include
soap, vinegar, and rubbing alcohol.
Antibiotics – medicines in the body that
target bacteria and fungi; may
include penicillin, amoxicillin,
streptomycin, and tetracycline
The Diseases Strike Back
Antibiotic resistance – when bacteria
mutate so that they are no longer
affected by anitbiotics
Fighting Disease
Vaccines – medicines that are actually
weakened forms of pathogens to
activate your memory cells so that
you don’t get sick
The memory cells kick in immediately
the second time a pathogen is
experienced in the body
Fighting Disease
There are 4 types of vaccines:
1. Whole vaccines – whole dead
bacteria or viruses
2. Live attenuated vaccines – weak
living pathogens.
Fighting Disease
3. Component vaccines – use only
part of the pathogen (usually
the membrane with the
antigen on it)
4. Toxoid vaccines – inactivated
bacterial toxins; e.g. botox,
tetanus vaccine
Immune System Diseases
1. HIV – Attacks the T cells in the
immune system; HIV patients
usually get sick from all the other
disease that can now enter the
body.
2. Leukemia – cancer of the white
blood cells; they shut down or start
fighting the body themselves
Autoimmune Diseases
Multiple sclerosis – the WBC’s attack
the nerve cells; you lose
coordination
Lupus – the WBC’s attack the body
Cycles
• Lytic and lysogenic cycle
•
• Bacteriophage - virus that infects a
bacteria
• Lytic - "lyse" to burst
• Lysogenic - to hide
Cycles