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Immune System
(Why I shouldn't be here!!)
Immune System
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What the Immune System Is
●
What the Immune System Does
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What makes up the Immune System
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How the Immune System works
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Medical Issues
●
Research tools
What the Immune System Is
Common Definition:
What stops us getting ill
Scientific Definition:
Biochemical complex that protects the
body against pathogenic organisms and
other foreign bodies (Mosby)
What the Immune System does
C
O
N
T
R
O
L
Wanted
Bacterial Infections
Viral Infections
“House Keeping”
Cancer
Parasites
Unwanted
Allergy
Autoimmunity
Medically
related effects
Inoculation / Vaccination
Grafts / Transplants
Blood transfusions
Immunoassay
Research tool
Immune System
Stem Cell
Platelets
(thrombocytes)
Red Blood Cells
(erythrocytes)
White Blood Cells
(leucocytes)
7-8 days
80-120 days
Eosinophils
Lymphocytes
Basophils
Monocytes
Neutrophils
Macrophages
Innate Immunity
Phagocytes
T Cells
B Cells
Acquired
Immunity
Cell-mediated
Immunity
Antibody-mediated
Immunity
Immune System
Phagocytosis
White Blood Cell
(Neutrophil)
Tonsils
Lymphoid Tissue
Thymus
T-Cells are
primed/modified in THYMUS
Spleen
B-cells are primed/modified
G ut
A ssociated
L ymphoid
T issue
B- and T-cells enter lymphoid
tissue and are activated by
exposure to ANTIGENS
elsewhere
ANTIGEN
A substance (usually protein)
recognised as 'foreign' that
stimulate antibody formation
ANTIBODY
A protein (immunoglobulin = Ig)
produced in response to an antigen
Human antibodies are “Y” shaped
There are 5 sorts (IgA; IgD; IgE;
IgG; IgM)
Each sort of antibody has a
characteristic distribution and
function. For example, IgE is
concentrated in lungs & skin and is
associated with allergies
file:///D:/Human
%20Antibody
%20Yshaped
%20IMG.jpg
T- and B-Cells are exposed to antigens in lymphoid tissue.
This changes them so that they
can act against specific pathogens,
helped by and helping the
“Generalists” I.e Innate Immunity
Stem cells
in bone
marrow
Inactive
T-cells
Lymph
node
Differentiation
of T-cells
Activated T-cells
Cellular Immunity
Thymus
Antigen
Activated B-cells
Site of B-cell
differentiation
(unknown)
Inactive
B-cells
Antibodies
Activated T-Cells
release CYTOKINES
Cytotoxic/Natural
Natural Killer / Cytotoxic
Killer/CD8/T-cells
CD8 T-cells
•
Activate
other white
blood cells
•
•
Destroy virus infected cells
▪ Destroy virus infected cells
Destroy cancer cells
Destroy damaged▪ cells
Destroy cancer cells
▪ Destroy damaged cells
Activate more
macrophages
Suppressor T-cells
Reduce intensity
of
Suppressor
T-cells
immune response if
▪ Reduce intensity of immune
appropriate
response if appropriates
Enhance B-cells
(antibodies)
Helper T-cells (CD4)
Memory T-cells
Memory T-cells
•
•
Ensures faster response when
▪ Ensures faster response
antigen next encountered
when antigen next
Long-lived >20years
encountered
▪ Long-lived >20Years
•
•
•
•
Enhance antibody production
Helper/
Enhance NK
cells CD4 T-cells
Enhance suppressor
cells antibody production
▪ Enhance
Enhance macrophages
▪ Enhance NK cells
▪ Enhance Suppressor cells
▪ Enhance macrophages
Lymph drains in from tissues carrying pathogens
T-cells and B-cells are
activated by exposure
to antigen
Activated B-cells produce antibodies that 'match' the antigen
Neutrophils and other phagocytes destroy inactivated pathogens
B-cells exposed to
different antigens
Memory B-cells
ensure faster
response next time
Each B-cell line produces antibodies
that 'lock' onto that antigen, making
the pathogen easier to combat
Neutrophils and
other phagocytes
destroy inactivated
pathogens
Immune System
INFLAMMATION
Protective response; eliminates cause of cell damage and to initiates repair
Occurs in all physical and some psychiatric conditions
Persistent (chronic) inflammation can be harmful
Redness
blood flow
Heat
Swelling
WBC to site
CHRONIC
inflammation
RECOVERY
Persistent destruction
& healing
Wanted
Bacterial Infections
Viral Infections
“House Keeping”
Cancer
Parasites
Unwanted
C
O
N
T
R
O
L
Allergy
Over reaction to substance that is inherently harmless
Ranges from trivial (eg mild hayfever) to life-threatening (eg shellfish; nuts)
Unwanted
Autoimmunity
Numerous very debilitating diseases eg
●
Type I diabetes (insulin dependent)
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Rheumatoid Arthritis
●
Multiple Sclerosis
In Coeliac disease, presence of GLUTEN (protein in wheat that helps
bread rise) induces AUTOIMMUNE response, resulting in destruction
of absorptive surface of gut
Medically related effects
Inoculation / vaccination
Introduction of a small amount of viral material,
usually though the skin, as PREVENTATIVE
Small pox (variola major) was a
horrendous much feared disease.
The only preventative was variolation
(introducing live small pox into the
body) which had at least a 1%
mortality rate.
Edward Jenner (1749-1823)
noticed that people who'd had COW POX
did not get the much more severe small pox.
He pioneered inoculating virus from cow-pox
scabs as a preventative for small pox.
Medically related effects
Blood Transfusions
(cells or plasma)
Transfusion compatibility for RBC
Receive
from A&O;
Donate to
A or AB
ABO Blood Groups
This is most significant
blood grouping
Receive
from B&O;
Donate to
B or AB
Universal Recipient Receive ONLY
from O but
Donate ONLY to
Universal Donor
AB
Medically related effects
Why I shouldn't be here!
Rhesus Factor (Rh) is second most important Blood Grouping
Rh-ve mother with Rh-ve baby = No Problem
Rh-ve mother with Rh+ve baby = No Problem for FIRST baby.
BUT, during birth some Rh+ve cells may enter maternal
circulation causing woman to create Anti-Rh Antibodies
Rh-ve mother with 2nd Rh+ve baby – maternal anti-Rh
antibodies can damage baby's rbc, resulting in haemolytic
disease of new born (“Blue Baby”)
Organ / Tissue transplants
Major Histocompatibility Complex (MHC) [also called Human Leucocyte
Antigens HLAs] on donor cells' surface provoke immune response in recipient
The donated organ / tissue can be damaged or “rejected” by the recipient's immune system
Transplanting only ABO compatible grafts helps avoid ANTIBODY mediated rejection
Transplanting organs that have (as nearly as possible) matching MHC helps
avoid rejection mediated by
NK T-cells,
PHAGOCYTES and
ANTIBODIES
Research
Immunoassay Uses antibodies to latch onto, and so detect and quantify antigenic macromolecules
Advantages over other detection methods include high degree of sensitivity and/or specificity
Effective in biological fluids
Eg – drugs (therapeutic, recreational, performance enhancing) in blood or urine
- diagnostic (eg HIV, prostate specific antigen (PSA) for prostrate cancer, Hepatitis
- pregnancy testing kits
- pollutants in water
- analysis of food
Research tool – used to identify CH-markers on T-cells which in turn helped
resolve action of different types of T-cell
Reportedly worth US$ 17 Billion in 2012
Final message
LOOK AFTER YOUR IMMUNE SYSTEM
AND IT WILL LOOK AFTER YOU!!
Thank you!