1. Unit 4 - Immunology and Public Health

2. 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

3. 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 …..
describe how HIV overcomes the immune response
describe how TB can avoid the immune response

4. 2. Direct attack on the Immune System
The absence or failure of some component of the immune system results in increased susceptibility to infection.

5. Direct attacks on the immune system
HIV infection

6. Symptoms of HIV infection
Oral candida is a common symptom
Body cannot defend against the fungus that causes oral thrush
Lesions form on the chest and develop all over the skin

7. Human Immunodeficiency Virus
AIDS is a deficiency disease caused by the HIV virus.
The glycoproteins on the HIV attach to the receptors on the T-helper cells.
The virus infects the T-helper cell, replicates, leaves by budding and infects more T-helper cells.
The membrane of the T-helper cell becomes punctured, leaving the cell destroyed.
As the number of T-cells drop, the person becomes more susceptible to infections (pneumonia, rare forms of cancer)
Remember, helper T cells are of critical importance to the immune system – they activate B cells and cytotoxic T cells

8. Direct attacks on the immune systemTB
– call me maybe version!

9. Symptoms of Tuberculosis
TB disease symptoms may include:
A bad cough that lasts 3 weeks or longer.
Pain in the chest.
Coughing up blood or sputum (phlegm from deep inside the lungs)
Weakness or fatigue.
Weight loss.
No appetite.
Chills.
Fever.

11. Tuberculosis Bacteria
TB is an example of where a pathogen hijacks the immune system for themselves.
They allow themselves to be engulfed by phagocytes but prevent the lysosomes fusing with the vacuole they are in. They also have a waxy coat to prevent them being digested even if they did come into contact with it.
The pathogen remains alive inside the phagocyte and avoids immune detection and destruction.

12. Can you now … describe how HIV overcomes the immune response
describe how TB can avoid the immune response

13. You have now completed Key Area 4 and ALL of Unit 4! 

14. 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
state why clinical trials are important
describe what is meant by a randomised, double blind, placebo-controlled protocol.
state what is meant by herd immunity
describe the benefit of herd immunity to non-immune individuals
describe the importance of herd immunity in reducing the spread of disease
state that the herd immunity threshold depends on a number of factors
give examples of barriers to herd immunity in the developing world
give examples of barriers to herd immunity in the developed world
describe the process of antigenic variation
give examples of pathogens that use antigenic variation
describe why antigenic variation poses a problem to public health
Describe how to set up an experiment to view the antibody-antigen interaction
describe how HIV overcomes the immune response
describe how TB can avoid the immune response