Download Immune System & Disease

IMMUNE SYSTEM &
DISEASE
A Brief Introduction
What Is Your Immune System?



AAAACHHOOO!! Your
friend has a terrible
cold, and he sneezes
right next to you without
covering his mouth.
Not only is this gross, it
sprays millions of cold
viruses into the air
around you.
Luckily, you don’t get
sick. Why not?
Your Immune System


Our bodies have an
amazing internal
defence mechanism
called the immune
system which protects
you from bacteria and
viruses that can lead to
illness.
A healthy immune
system produces a
variety of different cells
to attack the invading
bacteria and viruses
Your Immune System



Your blood contains
many different types of
cells
Red blood cells carry
oxygen to all the parts
of your body
White blood cells,
known as leukocytes
(LUKE-oh-sites), make up
the immune system
portion of the blood.
Your Clever Immune System



How does your immune system know which cells to
attack and which cells are part of your own body?
Your immune system can recognize cells based on
the proteins present on the surface of cells.
Viruses, bacteria, and other foreign cells are
recognized as being different from your own cells
and are attacked by your immune system.
However.....



Sometimes, one of your own cells changes, or
mutates, giving the cell the ability to multiply
continuously.
Such mutations often are the cause of cancer
Your immune system has the ability to recognize
mutated cells and attack them before they can
grow into a tumor.
But It’s Not Foolproof....


Not only can certain viruses outwit your immune
system's defences, but genetic malfunctions can
result in an ineffective immune system.
If enough cells are killed, the immune system no
longer functions and the person becomes susceptible
to many different diseases.
Disease


Illness or sickness often characterized by typical
patient problems (symptoms) and physical findings
(signs).
Diabetes, cancer, genetic diseases, immune system
diseases, etc.
Antibiotics


Antibiotics inhibit and prevent the growth of
bacteria
Antibiotics DO NOT affect viruses, fungi or other
microbes
Antibiotics



Antibiotics that destroy bacteria are termed
bactericidal (“bacteria killing”)
Antibiotics that prevent bacteria from multiplying
are termed bacteriostatic (“bacterial inhibiting”)
Type of infection dictates what type to use!
Bacteriostatic Antibiotics



Prevent cell wall formation during cell division of
gram positive bacteria
Penicillin destroys the bacterial cell wall making the
bacterium very susceptible to damage.
Erythromycin and tetracycline disrupts bacterial
protein synthesis by binding to their ribosomes and
inhibiting translocation
Antibiotics

Once, there were only natural products:
a) Penicillin came from the fungus genus Penicillium
b) Streptomycin came from the bacteria genus
Streptomyces
Antibiotics


Now, many can be chemically synthesized with all
the advances in organic chemistry
Example: sulfa drugs were the first synthetic drugs
with widespread antibiotic activity to be put into
clinical use in the 1930s
Antibiotics
Oral antibiotics are
ingested
e.g.- For strep throat, urinary
tract infection
 Intravenous antibiotics are
used in more serious cases
e.g.- For deep infections of
body systems like infection
after surgery, sepsis, flesh
eating disease (necrotizing
fasciitis)

Antibiotics


Topical antibiotics are
placed on the skin
Eye drops for pink eye
or ointment for a skin
infection
Antibiotic Resistance



Occurs when bacteria in your body change so that
antibiotics don't work effectively to fight them
anymore
Can happen when bacteria are repeatedly
exposed to the same antibiotics or when bacteria
are left in your body after you have been taking an
antibiotic (such as when someone does not take the
full course of their antibiotic medicine)
These bacteria can multiply and become strong
enough to resist the antibiotic in the future.
Interesting to Know...




Links have also been made between giving drugs to
animals and the development of resistance in humans
Drugs are often given to food-producing animals to
treat and prevent infections in the agri-food industry
and to promote growth
In the U.S., 50% of antibiotic use is in farm animals in
the absence of disease!!
There are many organizations and 2 federal U.S. Bills
which are trying to restrict antibiotic use in food animal
production
Farm Animals & Antibiotic Resistance



Products are also sprayed on fruit trees to prevent
or control disease
These can then be transferred to humans in meat,
milk, fruit or drinking water, adding to the resistance
problem
An example of this is drug-resistant Salmonella,
which can be transferred from animals to humans
through the food chain
Antibiotic Resistance
The Result?



Misuse and resistance causes low cost antibiotics to
be useless - meaning we must use more expensive
and newer compounds
The fear is that eventually we will not be able to
keep up with the race to create new antibiotics for
bacterial infections
Is research into bacteriophages for use as
antibiotics; appear to be several types of
bacteriophage that are specific for each bacterial
taxonomic group species