Human Defence System
Immunity induced by inoculation (injection) OR
Once infected by micro-organisms, antibodies are formed which kill
the micro-organisms and prevents further infection.
Long-term immunity resulting from the production of antibodies by:
1. inoculation (the injection) of vaccine containing a weakened
strain of a pathogen or its toxin, or
2. an infection by a pathogen.
Substance naturally produced by living micro-organisms (e.g.
Penicillium notatum) which destroys or inhibits the growth or
reproduction of other micro-organisms, especially bacteria or fungi,
e.g. penicillin, streptomycin, tetracycline, etc. These substances have
no effect on viruses.
Protein substance produced by lymphocytes (white blood cells) in
the immune system to attack and destroy or counteract antigens
(micro-organisms or their products). They are specific.
A reaction between an antigen and an antibody resulting in the
neutralisation or elimination of the antigen.
acquired
immunity (active)
active immunity
antibiotic
antibody
antigen antibody
reaction
(response)
A substance (e.g. a micro-organism or its waste products – proteins
or polysaccharides) that the immune system of the body recognises
antigen
as ‘foreign’ and as a result will produce antibodies that will react
with it and neutralise or destroy it.
Serum from the blood of humans or animals that contains antibodies
specific to certain pathogens. When injected into a patient, recovery
antiserum
is almost guaranteed but the patient will not retain any immunity to
the disease. The immunity is passive and short-term.
Pathogen whose virulence (i.e. ability to cause a disease) has been
lessened, and will not usually cause a disease.
attenuated
organism
A number of blood proteins that make holes in the surface of
bacteria and viruses causing them to burst.
complement
proteins
Prevents the entry of microbes (by acting as a barrier) and destroys
microbes once they get inside the body. Composed of: the skin,
blood clotting, respiratory system, digestive system, body fluids and
phagocytes. Does not involve antibodies.
A type of lymphocyte that stimulates the production of antibodies
by causing the B-cells to reproduce when an antigen is present. Also
stimulates other T-lymphocytes (killer & suppressor) to work and
enhance their effectiveness.
The production by the body of a reaction to infection. The primary
reaction takes place when the foreign protein (antigen) and antibody
meet. A secondary reaction takes place on subsequent encounters
with the same antigen.
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general defence
system
helper T-cells
immune response
Protective methods the body has to keep it safe from disease or
disease causing organisms (pathogens) and provides defence against
the growth of cancer cells. The system is composed of the spleen,
thymus gland and lymph nodes.
immune system
The ability of the body to resist infection.
immunity
To give the body the ability to fight infection using antibodies that
are produced by (a) suffering the illness or (b) by vaccination. It can
be active or passive.
induced immunity
Injection containing a vaccine or weakened form of a disease to
stimulate the body to protect itself against the disease.
inoculation
Lymphocytes that attack large pathogens, e.g. unicellular parasites.
They destroy cancer cells and cells containing viruses. Produce a
chemical called perforin that punctures cell membranes.
Lymphocytes that are long-lived in the circulatory system. Produced
when T-lymphocytes are stimulated. They remember the immunity
and provide a rapid response for successive exposures to an antigen.
The ability of the body to resist infection but does not involve the
production of antibodies.
Recipient receives antiserum, containing antibodies, from an already
immunised individual. This confers short-term immunity on that
individual, e.g. tetanus and newborn babies.
Chemical produced by killer T-cells that perforates cell membranes.
Plasma or extra-cellular fluid can then enter the cells and cause
them to swell and burst.
Composed of the organs of the immune system that react to the
presence of antigens by producing antibodies. This confers immunity
which usually lasts a long time.
Lymphocytes that can hold back the immune response of B-cells and
other T-cells. Prevent the immune system from over-reacting, i.e.
they shut off the antibody production when an infection is under
control. Regulates the immune system.
Process of injecting a vaccine (which acts as an antigen) into a
person in order to induce immunity. This results in the production of
antibodies against the antigen.
A suspension of living, dead or attenuated pathogens which act as
an antigen causing the body to produce antibodies that render the
body immune to infection by the specific pathogens.
killer T-cells
memory T-cells
natural immunity
passive immunity
perforin
specific defence
system
suppressor T-cells
vaccination
vaccine
The infectious part of a virus consisting of the RNA or DNA and the
protein coat.
virion
Poisonous, malignant, noxious, highly infectious.
virulent
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