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

Can you now …. describe what is meant by Immune Surveillance describe what is meant by Clonal Selection Theory describe the specificity of lymphocyte receptors describe the roles of 2 types of T-lymphocytes in response to infection describe the role of B-lymphocytes in response to infection describe what is meant by immunological memory state the benefits of having memory cells. describe the role of T lymphocytes in recognising self and non-self explain what is meant by an autoimmune disease in relation to lymphocyte regulation state what is meant by the term ‘allergy’ and give examples of common allergic reactions

Quick Questions Describe when a clonal population of lymphocytes would be produced in the body? If each lymphocyte can only recognise one specific antigen, how is it possible that lymphocytes offer effective protection against a wide variety of pathogens?

Quick Questions 2 types of lymphocytes are produced. Explain the role of the lymphocyte which is involved in cells self-destructing. What is produced by B-lymphocytes during the immune response? 3. Name 3 possible effects of the protein produced by B-lymphocytes The lymphocyte involved in cell destruction is the cytotoxic or killer T cell. It induces apoptosis in infected cells Antibodies specific to the antigen

Quick Questions Inactivate a pathogen or toxin 3. Name 3 possible effects of the protein produced by B-lymphocytes Inactivate a pathogen or toxin Render it more susceptible to phagocytosis. Stimulate a response which results in cell lysis.

Quick Questions Name cell Q Describe 2 functions of cell P as shown in the diagram. Name cell P Antibody producing B lymphocyte Recognise foreign antigens and copy itself to produce a clonal population of B cells B Lymphocyte

Quick Questions For each statement below state if it refers to the 1st or 2nd exposure of a pathogen Larger concentration of antibodies produced Clonal population of lymphocytes occurs faster Memory cells are produced Immune response is longer Illness occurs

Questions – 12 minutes! What are the two types of lymphocytes? Where do T lymphocytes mature? Why are cytokines released at the site of infection? What is the name of the proteins found on cell surfaces that trigger an immune response? Describe clonal selection. a) What is autoimmunity? b) Give a condition linked to autoimmunity. 7) How does a TC cell lead to the destruction of an infected cell? 8) a) What does an activated B cell produce? b) How do these molecules bring about destruction of a pathogen? 9) What term is used to describe the first infection of the body by a pathogen? 10) If the body is re-infected at a later date, what is this known as? 11) Which cells are central to being able to fight off re-infection? 12) How does the immune response to the second infection compare to the first?

Answers B and T lymphocytes The thymus gland To activate B lymphocytes and phagocytes Antigens The binding of a lymphocyte receptor to an antigen activates the lymphocyte which leads to it dividing producing a clonal population of lymphocytes. a) An immune response against self antigens by T lymphocytes b) rheumatoid arthritis / Type 1 diabetes / multiple sclerosis. 7) Induces apoptosis (programmed cell death) 8) a) Specific antibodies that recognise a specific antigen b) when an antibody-antigen complex is formed the pathogen is inactivated OR it renders it more susceptible to phagocytosis OR stimulates a response which results in cell lysis 9) Primary exposure 10) Secondary exposure 11) Memory cells 12) The second response produces a larger concentration of antibodies and does it faster than the first response

Quick Questions Choose the correct words from the box below to describe what is meant by the term allergic reaction What cell is involved in autoimmune diseases? Explain the role of this cell in autoimmune diseases > Under-reacts > Hyposensitive response > Over-reacts > Normally harmful substance > Hypersensitive response > Normally harmless substance

Questions & ANSWERS What are the two types of lymphocytes? B and T lymphocytes Where do T lymphocytes mature? The thymus gland Why are cytokines released at the site of infection? To activate B lymphocytes and phagocytes What is the name of the proteins found on cell surfaces that trigger an immune response? Antigens Describe clonal selection. The binding of a lymphocyte receptor to an antigen activates the lymphocyte which leads to it dividing producing a clonal population of lymphocytes. a) What is autoimmunity? An immune response against self antigens by T lymphocytes b) Give a condition linked to autoimmunity. rheumatoid arthritis / Type 1 diabetes / multiple sclerosis. Useful for show-me-boards

Questions & Answers 7) How does a TC cell lead to the destruction of an infected cell? Induces apoptosis (programmed cell death) 8) a) What does an activated B cell produce? Specific antibodies that recognise a specific antigen b) How do these molecules bring about destruction of a pathogen? when an antibody-antigen complex is formed the pathogen is inactivated OR it renders it more susceptible to phagocytosis OR stimulates a response which results in cell lysis 9) What term is used to describe the first infection of the body by a pathogen? Primary exposure 10) If the body is re-infected at a later date, what is this known as? Secondary exposure 11) Which cells are central to being able to fight off re-infection? Memory cells 12) How does the immune response to the second infection compare to the first? The second response produces a larger concentration of antibodies and does it faster than the first response Useful for show-me-boards