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Immunization

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Development of vaccines

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What are vaccines?

A vaccine contains a small quantity of dead or weakened

disease-causing material. However, the pathogen or

antigenic material of the pathogen is harmless.

When this pathogenic material enters

the blood, the antigens on the

pathogen stimulate the production of

antibodies and memory cells.

Antibodies act against the target

pathogen, without making the person ill.

If a vaccinated person is later infected

by the same pathogen, their immune

system can destroy it very quickly.

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How do vaccines work?

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Fill in the gaps about vaccinations

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Scientists can never determine that a drug or vaccine is

100% safe or completely risk free. With vaccines, genetic

differences might lead to some people experiencing

unexpected side effects.

However, vaccines are not used unless

doctors are sure that the probability of

something going wrong is very low.

What is an acceptable level of risk?

How do you think the following factors affect the decision as

to whether a vaccine should be used?

how severe the potential side effects are

how serious the disease is, if caught.

Safety of vaccines

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Opinions on vaccinations

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Benefits and risks of vaccination

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Class vote

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Lymphocytes

Collectively, they recognize

millions of different antigens,

due to the large variation of

lymphocytes produced.

Lymphocytes are a type of white blood cell found in the

blood and lymph nodes. There are several different types

of lymphocyte, including memory lymphocytes.

Memory lymphocytes are

produced in response to a

vaccine or infection and

recognize antigens.

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Memory lymphocytes

Memory lymphocytes play a role in the antibody-mediated

response that generates antibodies to target the pathogen.

Once a memory lymphocyte has been generated, it will

circulate in the bloodstream even after the pathogen has

been destroyed and removed. If stimulated, they divide and

rapidly produce antibodies against the specific pathogen.

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Antibody levels after infection

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What are monoclonal antibodies?

Polyclonal antibodies are naturally produced in an immune

response, where different lymphocytes secrete a variety of

antibodies against a specific antigen.

Monoclonal antibodies (mAbs) are

artificially produced from clones of a

single lymphocyte and are identical.

They have important uses, including:

drug screening

treatment of cancer and blood clots.

home pregnancy kits

scientific research

A specific type of lymphocyte produces antibodies that

target pathogens in the body.

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Production of monoclonal antibodies

Large quantities of monoclonal antibodies are often

produced by injecting a specific antigen into mice or rabbits.

This stimulates the production of the animal’s lymphocytes.

The lymphocytes are

removed from the animal

and fused with cancer cells

that have been made

harmless. These form

immortal hybridoma cells.

Hybridoma cells are able to

divide and produce a single

type of antibody continuously.

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Monoclonal antibody therapy

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Glossary

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Multiple-choice quiz