Vaccinations, White Blood Cells, Antibodies and Antigens

Contents:

1. Vaccinations

2. White Blood Cells, Antibodies and Antigens

3. Example questions

1. Vaccinations

Vaccinations allow us to develop immunity to various disease so that if we are attacked by the pathogen, it doesn’t make us ill.Vaccination involves injecting a dead or inactive form of the pathogen into a person which stimulates white blood cells to create antibodies to fight that pathogen.

1. Vaccinations continuedThe process of vaccination is:1. A person is injected with a dead or inactive form of the

pathogen2. This stimulates white blood cells to create antibodies to

fit the antigens of the pathogen to fight it off3. If the pathogen attacks again, the antigens are

recognised and white blood cells remember the antibodies needed to fight that specific pathogen

4. The antibodies are created quicker than before and in a higher quantity, also the concentration of antibodies in the blood stays higher for a longer period of time

5. The pathogen is killed before it has time to make the person ill, the person is immune.

1. Vaccinations continuedAdvantages of Vaccinations:1. Vaccines have helped control lots of infectious diseases that

were once common e.g. polio, measles, whooping cough, rubella, mumps and tetanus. Smallpox is no longer existent and polio infections have fallen by 99%

2. Epidemics of disease can be prevented if a large population have been vaccinated. That way, even un-vaccinated people are unlikely to catch the disease as there are fewer people to pass it on. However, if a large amount aren’t vaccinated then a disease can spread quickly and lots of people will be ill at the same time.

Disadvantages of Vaccinations:3. Vaccines do not always work-sometimes they don’t give

immunity4. People can have bad reactions to a vaccine e.g. swelling, fever,

seizures. However bad reactions are quite rare.

2. White Blood Cells, Antibodies and Antigens White Blood Cells travel around the body in the bloodstream and are

continuously looking out for microbes entering the body. They have three ways of combating the invading pathogens:

1. Consuming them- White Blood Cells can engulf pathogens and digest them

2. Producing Antibodies- Pathogens have antigens on their surface. When WBC’s come across an antigen they don’t recognise they start producing proteins called antibodies to lock onto and kill the pathogen. The produced antibody is specific to that type of antigen and therefore pathogen and won’t lock onto any others. These antibodies are then produced rapidly and are carried around the body to kill all similar pathogens. If the person is infected with the same pathogen again, the WBC’s produce the antibodies for that pathogen quicker and in a higher quantity; these kill of the pathogen before it has time to make the person ill. The person is naturally immune.

3. Producing Antitoxins- Pathogens create toxins which are the things that make a person ill. The WBC’s produce antitoxins to counteract the effects of the toxins

3. Example Questions1. A vaccine contains an .................. form of the pathogen (1)2. The vaccine stimulates the white blood cells to produce ............. (1)3. A person has been vaccinated against measles. The person comes into

contact with the measles pathogen. The person does not catch measles. Explain why (3)

4. Compare how effective introducing the measles vaccine was with introducing the MMR vaccine. Use the data from the graph (3)

ANSWERS

3. Example Questions: Answers1. -Inactive (1)

2. -Antibodies (1)

3. -White blood cells produce/ release antibodies (1)-Antibodies produced quickly (1)-(These) antibodies destroy the pathogen (1)

4. -Both lead to reduction/fall (in measles cases) (1)-Measles caused a big drop or correct use of figures

(1)-MMR wipes out measles or drops to (almost) zero or doesn’t fall as much as measles vaccine (1)