Lecture - Infection & Immunity (Immune Markers in Infection)

Question 1

Okay so there is two types of immunity - humoral (B cell, ABs) and cellular (T cells)

You can either detect the infectious agent or detect the immune resopnse (AB or T cell response)

I am going to list the ways to measure antigen and antibody - you need to explain to a wall how each works:

1. Agglutination
   - how does it measure both the antigen and AB?
   - If positive, what do you see?
2. Immunuoflorescence
   - there are two types of this - what are they and how do they work?
   - what’s a flurochrome?
3. Neutralisation
   - how is this a more specific measure?
4. Enzyme immunoassay
   - what big disease that you learnt about is this test used for?
   - what will the wells look like if they have more AB present vs less AB present?
   - what’s the opposite version of this?
   - how do rapid HIV, pregnancy tests etc work?
5. Western blot
   - is this still sorta used these days?
   - can it detect antigen?
6. Immunochromatographic test

Answer 1

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Question 2

Allergy

1. How many types of allergies are there?
2. Type 1 hypersensitivity:
   - what AB is it mediated by?
   - what molcule is released?
   - wha coditions is this to do with?
   - explain the process
   - look at measure of what to measrue this?
3. Type 4 hypersensitivity
   - what is it mediated by?
   - what conditions
   - what do you use to test this?

Answer 2

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Question 3

Skin prick testing for type 1

1. How does it work?
2. What will you see? (W___-and-F____)

Patch testing for type 4

1. How does this one work?

Tuberculin skin test - type 4 hypersensitivty

1. How does it work?
2. What do you see?

Interferon-gamma release assays (IGRAs)

1. First of all, how is ifg actually released? (diagram slide 23)
2. How does this test work? What does it involve?

Question 4

Did infection occur recently?

1. In a primary immune response, what are the levels of IgM and IgG like on a graph with time on the x axis and antibody titre on the y?
2. So if you have IgM negative and IgG positive, is the infection recent or distant?
3. What about IgM positive and IgG positive/negative?
4. IgM can be p____ or reactived
5. When do you measure the early (acute) sample and when do you measure the convalescent sample?
6. What is seroconversion? (2 things) - this is what you will see going from acute to convalescent
7. If acute sample is too late then already near plateau - what does that mean for seroconversion?
8. What is somatic hypermutation?
9. What is avidity? What is affinity? In early infection, do you have high or low avidity? What about distant infection?
10. Slide 34 - generation of high affinity antibodies in germinal centre, how does it happen? Explain the process in detail
11. Measurement of IgG avidity - how do you do it? What role does urea play in this? What does the result of ‘0.33’ mean?

Answer 4

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