y8 humans 13 two types of immunity
DESCRIPTION
Year 8 Science lessonTRANSCRIPT
2 Types of Immunity
Learning Objectives:• Explain the difference between active and
passive immunity
White blood cells - recapEngulf Antibodies
Break cell wall Antitoxins
AntibodiesAntibodies attach themselves to the markers (antigens) on the bacteria.
Antibodies
The antibodies have to be the right shape to match the antigens.
Antibodies
The antibodies have to be the right shape to match the antigens.
Antibodies
Your body only knows what shape to make the antibodies after you have caught the disease and become ill.
Match the antibody to the microbe
a
b
d
c
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2
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Definition
Immune: Not being able to catch a particular disease because you have antibodies in your blood to fight it.
Definition
Vaccine: a dead or weakened version of a disease. Your body can make antibodies without becoming infected.
Vaccination
• Use these words to explain how a vaccine works
Inject dead/weakened antibodies
White blood cells microbe vaccine
Fighting diseaseNATURAL IMMUNITY
This is when antibodies are produced by a person when needed or they are passed on by the mother during pregnancy.
ARTIFICIAL IMMUNITY
Can be done in two ways:
1) A vaccine with dead microbes is injected – the body is “tricked” into producing antibodies ready for the real thing. This is called PASSIVE IMMUNISATION
2) The antibodies are injected directly into the body – this is called ACTIVE IMMUNISATION.
Acquired Immunity
Artificially acquired
Naturally acquired
Active
Active
Passive
Passive
•Antigens enter body naturally
•Antibodies & specialised lymphocytes produced
•Antibodies pass from mother to foetus
•Infant does not produce any antibodies of its own
•Antigens are introduced in vaccines
•Antibodies & specialised lymphocytes produced
•Antibodies are introduced in an immune serum
•Body does not produce any antibodies of its own
LLive attenuated ive attenuated (weakened)(weakened)
• Made from live virus • Altered to be less harmful• Oral polio, MMR and BCG, yellow fever
and one form of typhoid vaccine
Whole-agent Whole-agent vaccinevaccine
Inactivated (killed)• Inactivated micro-organism• E.g. Rabies, most influenza vaccines
Contains whole, non-virulent micro-organisms
Different defence mechanisms
Transmission of microbes
Disease defence - what’s the order?
2 Types of Immunity
Learning Objectives:• Explain the difference between active and
passive immunity