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Unit 4 Immunology and
Public Health
Unit 4 – Immunology and Public
Health
1. The Immune
System
a)Non-specific
defences
b)Specific cellular
defences
2. Infectious
Diseases and
immunity
a)Transmission and
control
b)Active
Immunisation and
Vaccination and
the evasion of
immune responses
1. The Immune System b) specific cellular defences
By the end of this section you will
be able to …..
• describe the role of T lymphocytes in
recognising self and non-self
• explain what is meant by an autoimmune
disease in relation to lymphocyte
regulation
• state what is meant by the term ‘allergy’
and give examples of common allergic
reactions
Decide if each card is
TRUE or FALSE
Crohns disease, type 1 diabetes,
Graves disease, psoriasis and
rheumatoid arthritis are examples of
autoimmune diseases.
Chicken pox, CJD, legionnaires’
disease and meningitis are examples
of autoimmune diseases.
An autoimmune disease is caused by
an overactive immune response in
which the body’s own cells are
destroyed.
Autoimmune diseases can be caught
from close contact with infected
people.
Treatment of autoimmune disease
only serves to alleviate the
symptoms, it does not cure the
disease.
Autoimmune diseases can be easily
cured with a combination of
antibiotics and anti-viral drugs.
There is no known prevention for
autoimmune disease.
Children can be vaccinated against
autoimmune diseases – this prevents
them from getting ill in later life.
Rheumatoid arthritis
In rheumatoid
arthritis,
cytokines cause
inflammation
which will
attack the bone
and cartilage in
joints, causing
them to be
replaced with
fibrous tissue
which leaves
the joint less
mobile than
before.
Type 1 diabetes
• Destruction
of Beta
cells
Graves disease
Psoriasis
skin condition that
causes red, flaky,
crusty patches of
skin covered with
silvery scales
Crohns diseases
Inflammation of the lining of
the digestive system (IBD)
Multiple
Sclerosis
Confusing self and non-self
• T-lymphocytes have specific surface proteins
that should be able to read the surface antigens
of a cell and tell if it is self or non-self.
• However, sometimes T-lymphocyte regulation can
fail
• T-lymphocytes fail to distinguish between the
surface proteins of the body’s own cells and
surface proteins on foreign cells and therefore
attacks body cells.
• The immune response against our own self cells is
called autoimmunity.
– Rheumatoid arthritis
– Type 1 diabetes
– Multiple sclerosis.
Confusing self and non-self
Allergies
• B-lymphocytes sometimes over-react to
harmless substances like dust, pollen and
feathers etc. or even medicines such as
penicillin.
• The hypersensitive B-lymphocytes release
antibodies which cause mast cells to release
histamine.
• Some allergies are so severe that they can
trigger anaphylactic shock where the
histamine causes such a huge drop in blood
pressure it can be life threatening.
Can you now ….
• describe the role of T
lymphocytes in
recognising self and
non-self
• explain what is meant
by an autoimmune
disease in relation to
lymphocyte regulation
• state what is meant by
the term ‘allergy’ and
give examples of
common allergic
reactions