Transcript The Immune System

The Immune System.
What’s up with that.
What is it?
• The immune system
is the network of
specialized cells
and organs that
work together to
defend the body
against attacks by
“foreign” invaders,
a.k.a. antigens, such
as bacteria or viruses
• An antigen is any
substance that
stimulates the
immune system to
make a specific
immune response.
Self/Non-Self Recognition
- THE MAIN, GENERALIZED FUNCTION OF IMMUNE CELLS
•
Every cell in a human’s body displays a “marker” or
“bar code” based on its major histocompatibility (MHC).
These “codes” or “markers” let the body know that those
cells are its own cells.
• Any other cells, that do not display the same MHC
“marker”, are recognized by the immune system as
“non-self” and are attacked.
So basically...
“If you’re not us,
you’re dead.”
– The Immune System
What are the general cells
that are involved when an
immune response is made?
• Macrophages
• Helper T-cells
• B-cells and Killer T cells
Macrophages
*THE BIG EATERS*
Macrophages are found in all
locations in the body, where
they await the entry of
foreign material which they
then wrap themselves around
and ingest. Macrophages are
the first immune cells to
perform the “self/non-self
recognition” function. They
identify antigens as “nonself”, and initiate the rest of
the immune response to
attack it.
• 1) They *gobble up* the
antigens
• 2) Break them up into
little pieces
• 3) Display the pieces the
helper T cells
Helper T Cells
the heart of the immune system
• The little pieces of the
antigen fit like keys into
locks found on helper T
cells, and thus "turn on"
these cells. Once turned
on, helper T cells then
direct traffic in the
immune system, using
chemical messengers
(called
interleukins/lymphokines)
to signal other immune
cells to get involved in the
battle.
The Helper T Cells “direct the
traffic” of the immune cells.
Helper T Cell
If the antigen is
recognized as
a germ or
bacteria,
the B-cells will be
signaled
If the antigen is
recognized as
a cancer or virusinfected cell,
the killer T cells
will be signaled.
B-cells
• B cells, once given the proper information from
helper T cells, secrete proteins called
antibodies.
Antibodies are “missiles” that move about our
specifically targeting foreign material.
bodies
• The B-cells bind and neutralize the germ, and
attract other immune system components which
facilitate the destruction of the antibody-labeled
target.
Killer T Cells
• Once given the "go" signal from helper
T cells, these cells will “cozy up”
beside cancer cells or virus-infected
cells and then "stab" them so that the
target cell ruptures and no longer
serves as a reservoir for viral growth or
as a cancer clone capable of
generating more progeny.
SO, for example…
• Suppose this cell
snuffs up a flu
virus.
We have a “nose”
(respiratory epithelial) cell
• We now have a
virus-infected
cell, which will
need to be
combated.
Step 1 =
Macrophages
•The macrophage wraps itself
around and ingests the infected
cell (the nose cell + antigen).
•The macrophage breaks it up
into little pieces, then displays it
to the helper T cells.
Step 2 
•The helper t cells recognize the
infected “nose” cell as a virusinfected cell.
•Because it is a virus-infected cell,
the helper t cells will signal the
killer t cells to destroy the antigen.
Step 3 
The killer T cells will move
right up to the virus-infected cell
and rupture it, so that the virus or
cancer can no longer grow or
multiply.
(If…)
• If instead the antigen was a
bacteria and not a virus, the
helper t cells would signal
the b-cells to destroy the
antigen.
Last but not least:
• Pieces of bacteria or virus from
either scenario are mopped up by
the macrophage scavengers.
We all have our flaws…
• Often the immune system has its flaws, and the body is unable to be
100% accurate in making its immune responses. This means that
there may be a glitch in either the process of the macrophages,
helper t-cells, b cells or killer T cells doing their jobs. The
functioning of these processes together make up the generalized
self/non-self recognition and attacking of foreign cells.
• So, if there is a problem with the immune
system, it generally means that the body is
unable to properly identify or fight off
antigens.
•
•
2 examples of immune system response “problems” are asthma and allergies.
Asthma and Allergies deal with “triggers” – in relation to the antigens that “trigger” the
immune response.
Asthma
What is it?
A chronic respiratory disease, in which the airways
unexpectedly and suddenly narrow, often in
response to an allergen, cold air, exercise, or
emotional stress
•
a.k.a. “chronic inflammatory
disease of the airway”
• Cause unknown
• Currently no cure
• Symptoms:
-shortness of breath
-tightness in chest
-coughing
-wheezing
•
•
•
•
Any age can develop it
Usually #1 chronic condition
found in young people; needs
monitoring and to be controlled
over a persons life time
Episodes vary from one to the
next
Can break out time to time
/wont appear for long period of
time
“Triggers”
• Anything that will cause
inflammation in the
airways
• 2 types: Inflammatory
and symptom
Inflammatory (allergic):
causes
inflammation/tightness
of the lungs airways
muscles
Symptom (non-allergic):
low chance at causing
inflammation; can set
off “twitchy” airways
(especially if airways
are already inflamed)
• Symptoms occur;
flow of airway is
interrupted as it
passes in/out of
lungs
• More inflammation;
more sensitive
airways becomemore symptoms
occur (muscles
circling airway; more
sensitive)
• Leads to breathing
problems
• Asthma patientsairways inflamed all
the time (certain
degree)
Controlling asthma-avoid asthma
triggers
-take medication
-form health care
team
-follow asthma action
plan
Treatments- (2 types)
-each medication
serves diff. purpose
Controllers: reduces
inflammation
Symptoms occur less &
less
Relievers:
lightens symptoms
right away
The 3 stages
1. Histamine release
2. Arachidonic acid
cascade
3. Leukotrienes
Histamine Release
• Important protein; entangled in many
allergic reactions
• Histamine-known as vasoactive amine
• Release of histamine:
-contributes to an inflammatory response
-constriction of smooth muscles occur
Allergies
• Often treated by antihistamines
Effects of Antihistamines:
-restrains histamines release of
inflammatory mediators by leukocytes
-results in neutralization of histamine
(deters histamine from
binding/activating immune related cells
in the area)
Arachidonc Acid
Cascade
• series of chemical reactions that make
leukotrienes
• Response to many inflammatory stimuli
(change in internal or external
environment)
Leukotrienes
• Are naturally produced lipid mediators
Function:
-involved in asthmatic and allergic reactions
(leukotrienes act to maintain inflammatory
response)
Leukotrienes in asthma
• Assist in the study of the
biological and physical
reveal of the disease
(asthma)
causes these
symptoms:
-air flow obstruction
-increased secretion of
mucus
-mucosal accumulation
-Bronchoconstriction
-infiltration of
inflammatory cells in
airway walls
Role of Cysteinyl
Leukotrienes
• During interaction process, receptors
encourage pro-inflammatory activities
• Induces asthma and other inflammatory
activities which therefore reduces the
airflow to the alveoli
Allergies
Abnormal reactions to ordinarily
harmless substances.
Description
• Normally, the body learns to
defend itself through experience
through recognition.
– Vaccinations help create
immunity
• Allergic Reactions occur after
the immune system mistakenly
learns to recognize innocent
foreign substances (allergens) as
potentially harmful.
– Allergens can be inhaled,
swallowed, or come into
contact with skin.
Popular Allergens
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Pollen
Mold Spores
House dust mites
Animals
Foods
Insect bites
Latex rubber
Viruses
Bacteria
• …. And
much more!
Causes
• Fundamental cause
unknown
• Tendency to run in families
– genetic
• Infants that are breast-fed
are less likely to develop
allergies
• Expose to certain allergens
Symptoms
Mild
Moderate
Severe
Rash
Itchiness
a.k.a.
anaphylaxis
Itchy, watery
Difficulty
eyes
breathing
Swelling
Congestion
Can spread to Hard
other parts of breathing
Mild
body
reactions do
Abdominal
not spread to
pain
other parts of
Cramps
the body
Vomiting
Diarrhea
Treatment
• Antihistamines
– Triggers immune system to go to action. “Mast cells” in immune
system release histamine; causes blood vessels to enlarge redness,
swelling and itching. Block histamine receptors and prevent those
symptoms
• Over counter: Benadryl, Claritin, Dimetane,
Zyrtec
• Prescription: Clarinex, Allegram Astelin (nasal
spray)
…continues
• Decongestants
– Relieve congestion
– Allergic reaction cause tissue in nose to swell in response with allergies. The swelling produces
fluid and mucous. Blood vessels in eyes also swell which then cause redness. They shrink swollen
nasal tissues and blood vessels to relieve the symptoms of nasal swelling, congestion, mucous,
secretion and redness.
• Over counter: zyrtec-d, sudafed, Afrin (nasal spray)
• Prescription: Allegra-D
Anaphylaxis
severe, potentially life-threatening allergic reaction.
• Can occur within seconds or minutes of exposure to allergen
• The flood of chemicals released by your immune system during anaphylaxis can cause
you to go to shock; blood pressure drops and airways narrow- blocking normal
Causes
• Certain allergies make immune systems
overreact and when this happens the
immune system goes on a chemical chain
reaction= ANAPHYLAXIS
• Allergens: medication, foods (peanuts,
shellfish, etc), insect bites, etc
• Exercise
Symptoms:
• Skin reactions (pale, itching, hives, rash)
• Constriction of airways and swollen tongue/throat=
breathing trouble
• Weak and rapid pulse
• Nausea, dizziness
• Vomiting, diaherra
Complications
Can be life-threatening when a severe
anaphylactic attack occurs . It can stop
breathing and heartbeat.
Treatment
• CPR- Cardiopulmonary Resuscitation
• Epinephrine (adrenaline): reduce body’s allergic
response
• Oxygen- compensate restricted breathing
• IV antihistamines/cortisone: reduce inflammation
or airways
• Steroid Medication: treat and prevent prolonged
symptoms
• Always be properly stocked with medicines and
avoid allergens