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

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

Direct attacks on the immune system HIV infection https://www.youtube.com/watch?v=ng22Ucr33aw

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

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

Direct attacks on the immune system TB http://www.youtube.com/watch?v=IGZLkRN76Dc http://www.youtube.com/watch?v=gruBIZ0Bm-I http://www.youtube.com/watch?v=f5uq-ta4km0 – call me maybe version!

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.

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.

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

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

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