Unit 4 - Immunology and Public Health

Unit 4 – Immunology and Public Health 1. The Immune System 2. Infectious Diseases and immunity Non-specific defences Specific cellular defences Transmission and control Active Immunisation and Vaccination and the evasion of immune responses

By the end of this section you will be able to ….. 2. Infectious Diseases & immunity b) Active immunisation, vaccination and evasion By the end of this section you will be able to ….. State how active immunity can be achieved describe what a vaccine is describe the effect of a vaccine on the immune system immediately after vaccination describe the effect of a vaccine on the immune system when the body comes into contact with the same pathogen in later life Give examples of antigens used in vaccines

Active Immunity Immunisation is the process by which a person develops immunity to a pathogen Active Immunity is when the protection is gained as a result of a person producing antibodies There are 2 types of active immunity: Naturally acquired active immunity: a person who survives an infection by pathogens has naturally acquired immunity (by making antibodies and memory cells) Artificially Acquired Active Immunity achieved by vaccination

What is a Vaccine? Active immunity can be developed by receiving a vaccination. A vaccine is designed to illicit an immune response without producing the full blown infection. The vaccine is prepared with antigens from infectious pathogens

Vaccines There are 4 main types of vaccines which may contain: inactivated pathogen toxins dead pathogens, parts of pathogens (sub-unit) or weakened pathogens (attenuated)

DEAD – the pathogen is destroyed and cannot replicate itself e. g DEAD – the pathogen is destroyed and cannot replicate itself e.g. polio WEAKENED – the pathogen has been altered so it cannot cause the disease e.g. measles PART OF PATHOGEN – only the protein coat of the pathogen is used e.g. Hepatitis B INACTIVATED TOXIN – the toxins produced by the pathogen are injected e.g. tetanus antigen

Examples of antigens found in vaccines Form of antigen in vaccine Examples of disease to which active immunity is acquired Dead pathogens (the pathogen is destroyed and cannot replicate itself) Hepatitis A and polio Weakened pathogens (the pathogen has been altered so it cannot cause the disease) Rubella, mumps and measles Parts of pathogens (only the protein coat of the pathogen is used) Hepatitis B and HPV Inactivated toxin (the toxins produced by the pathogen are injected) Diphtheria and Tetanus

Adjuvants Antigens used in vaccines can also be mixed with an ADJUVANT This is a chemical that enhances the immune response Adjuvants promote the activity of the antigen in order to: To induce B cells to produce antibodies and cause the primary immune response. To produce memory cells so that they remain to give a faster secondary immune response if we ever come across the pathogen again.

This is how vaccines protect you against dangerous infectious diseases

How vaccines work (simplified) How vaccines work (includes B and T cells)

But what was the first vaccination?

The Smallpox Story video Watch the video (title)

Mass vaccination Edward Jenner was the first person to develop a vaccine. He noticed that people who had contracted cowpox were more likely to survive the deadly smallpox virus. He injected someone with cowpox and then exposed them to smallpox. This was the first ever vaccine and is named after the latin word for cow – vacca Through the use of vaccinations, smallpox is now eradicated around the world. We hope to eradicate more diseases using vaccination programmes. Complete the Edward Jenner Exercise. Read the exercise and answer the questions You can talk through this and do the reading exercise

Can you now …. State how active immunity can be achieved describe what a vaccine is describe the effect of a vaccine on the immune system immediately after vaccination describe the effect of a vaccine on the immune system when the body comes into contact with the same pathogen in later life Give examples of antigens used in vaccines