Immunity and Immunisation

L.O.

What I am looking for is for you to be able to explain and evaluate immunisation and immunity.

Starter

What diseases have you been immunised against and at what age?

April 21, 2023

Keywords

active immunity

antibodies

immune

Immunisation

Immunity

Inoculation

vaccination

vaccine

L.O.What I am looking for is for you to be able to explain and evaluate immunisation and immunity.

Age of person Vaccine

2-4 months Triple* and polio

15 Months MMR+

3-5 years Triple, booster MMR and polio

10-14 years Rubella (girls only)

13 years Tuberculosis (BCG)

Adults Tetanus every 5-10 years

* Triple (diphtheria, tetanus, whooping cough)

L.O.What I am looking for is for you to be able to explain and evaluate immunisation and immunity.

How immunity and immunisation works

Task:

While watching the video take notes on important key facts.

Painkillers can relieve the symptoms of an infection but do not kill the pathogen.

Invasion!A pathogen enters your body through direct or indirect contact. What happens next?

Your immune system begins to mount an attack.

The pathogen begins toreproduce and make toxins that destroythe body’s cells and make you feel unwell.

physical and chemical barriers

Lines of defence

most essential

mostcontrollable

non-specific defences

pathogen-specific defences

ingestion of bacteria by white cells

inflammationto attract white

cells into tissues

involves antibodies and T- and B-cells

The body has many different lines of defence:

Ingestion of microbes

Resisting attackTB bacteria have a number of adaptations that enable them to resist phagocytosis:

They produce chemicals that prevent white cells from being attracted to sites of infection.

They have a waxy cell wall that resists enzyme attack and secretes chemicals that block lysosomes from fusing with phagosomes.

Some TB bacteria are so successful at blocking one or more of the steps in phagocytosis that they are able to live and reproduce while ‘hidden’ inside macrophages.

How does the immune system deal with these bacteria?

What are lymphocytes?Lymphocytes are a type of white blood cell found in the blood or lymph nodes and made by bone marrow. There are several types of lymphocyte, including:

T-lymphocytes – recognise antigens on pathogens and either attack them directly or co-ordinate the activity of other cells of the immune system.

B-lymphocytes – recognise antigens and produce special chemicals called antibodies.

The third line of defenceAntibodies are specialY-shaped proteins produced byB-lymphocytes in response to antigens.

Antibodies work by binding to antigens on pathogens, ‘labelling’ them and causing them to clump together. The pathogen can then be destroyed by:

the antibodies themselves.

phagocytosis by macrophages

T-lymphocytes

AntibodiesEach different type of antigen causes a different type of antibody to be produced.

An antibody can only bind to the antigen that caused it to be produced.

Delayed responseThe B-lymphocyte that produces the correct antibody for the antigen begins dividing to produce many more antibody-producing cells.

It takes a few days to produce enough antibodies to destroy the pathogen. This means there is delay between infection and the person beginning to feel better.

Once a pathogen has been destroyed, a few memory cells remain. These recognize the pathogen if it re-infects, and make the immune response much quicker and more effective. This is called active immunity.

L.O.What I am looking for is for you to be able to explain and evaluate immunisation and immunity.

Task:

Draw a flow diagram (that includes pictures) to show how immunity and immunisation works. Include as many points as possible to get a level 7. You will be marking each others.

L.O.What I am looking for is for you to be able to explain and evaluate immunisation and immunity.

Levels for Afl and Peer assessment:-Level 3:• State that when microbes enter our bodies, white blood cells attack them. Level 4:• Phagocytes ingest bacteria and lymphocytes produce antibodies that

clump microbes together.

Level 5:• Immunisation is a way of protecting form microbes by taking in a

weak/dead form of the microbe so that antibodies are produced. • The microbe is then destroyed by phagocytes but the antibodies remain in

the blood stream for a long time.

Level 6:• That antibodies are produced by lymphocytes. They bind to the antigen on

the microbe. This clumps them together and not allowing the microbes to move. This allows the phagocytes to engulf them.

Level 7:• Draw diagrams to show antigen, antibodies, lymphocytes, phagocytes and

microbes.

Fighting an infection

Vaccines contain a small amount of dead or weakened pathogen particles.

What are vaccines?

A vaccine stimulates the production of antibodies and memory cells 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.

Parents of two-year-old children are offered a combined measles, mumps and rubella (MMR) vaccine to protect their child. What has happened to MMR vaccination rates recently?

Measles, mumps and rubellaMMR vaccination rates used to be high, but fell following a media scare story.

The media reported on controversial research speculating that MMR could cause autism, a behavioural disorder causing learning and communication difficulties.

Controversial dataHow was the research presented?

Would you worry if your child was due to be vaccinated?

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More evidence

Why are the results different? Who is right?

More detailed research carried out in Japan showed no link between the MMR jab and autism.

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MMR vaccine banned

Reassessing the evidenceIndependent expert scientists re-examined the original research and found no evidence of a link between the MMR vaccine and autism.

The original research failed to account for population growth or the fact that autism has became better understood by doctors and is now diagnosed more frequently.

If 95% of children had the MMR jab the diseases could be wiped out in the UK. This is called herd immunity.

However, many parents still distrust the MMR jab, preferring that their children receive single vaccinations or even no vaccination.

Benefits and risks of vaccination

L.O.What I am looking for is for you to be able to explain and evaluate immunisation and immunity.

Benefits and risks of immunisation

The MMR vaccine can only do good.

The MMR vaccine can only do harm