Immune Wokshop W3

Question 1

What is the difference between helper T cells and cytotoxic T cells?

Answer 1

H.T
• help to activate macrophages and B cells
• TH1 and TH2 cells release cytokines
• TH1 release IFN-y, TNF, IL-2
• TH2 release IL-4, IL-5, IL-10
• CD4+
• MHC class II

CT.T
• help kill any infected cells - cytolitic effect
• CD8+
• MHC class I - expressed in all nucleated cells
• release granzime and pertonins to directly kill off cells (1)
• FAS ligand react with FAS receptor leading to apoptosis (2)

Question 2

Explain why CD4T cells are important for your immune system

Answer 2

• CD4 T cells help activate other immune cells
• If we dont have CD4 we cannot activate macrophages or dendritic cells or B cells
• without B cells there is no antibody production so no IL-4 or IL-5 being secreted
• memory CD4+ T cells
• HIV affects CD4+

Question 3

Explain what positive and negative selection means for B and T cells

Answer 3

• T cells = thymus
• want weak reaction (+ selection)
• Don’t want strong reaction which could harm cells (- section)

• B cells = marrow
• dont want it to interact with anything in the bone marow
• self recognition needs receptor editing which leads to no recognition or the opposite, apoptosis
• if no slf recognition then that’s + selection

Question 4

How do antibodies work?

Answer 4

• looks like a Y with different regions
• activation of he compliment system
• neutralisation - stopping cellular entry or directly acting to sequest a toxin
• Agglutination/preciptation
• Optimisation

Question 5

How is the antibody diversity in our body created?

Answer 5

• somatic recombination / VDJ rejoining for heavy chain
• For light chain it is just VJ
• - V - D - J - -> - V - DJ - -> - VDJ -
• We can add or remove nucleotides which cause a frame shift
• Somatic hypermutation

Question 6

What happens in your body when you become infected with bacterium

Answer 6

1. Innate system is quic and non specific with NK, macrophages, neutrophils and cause compliment activation
2. Adaptive is slower and specific with T/ B cells

Question 7

Explain what happens in your body for you to experience an allergic reaction to pollen

Answer 7

• produce IgE antibodies specific to the allergen
• Need mast and allergen and IgE
• Histamine release bind to receptor -> vasodilation, mucus secretion, itching etc

Question 8

What are the main differences between first and second generation antihistamine?

Answer 8

1st
• lipophilic - cross blood brain barrier
• Sedating
• Not selective for histamine receptors
• Act on muscarinic receptors
• Anti colonergic effect
• Motion sickness

2nd
• cannot cross
• Non sedating
• more selective
• One a day

Question 9

Explain the difference between a type one and a type four hypersensitivity reaction

Answer 9

1
• activated by antibodies
• faster
• anaphylactic
• mast cells involved to release histamine
• IgE antibody
• chemotaxis

4
• cell mediated by T
• Slower - delayed onset

Question 10

Explain the pharmacology action of antihistamine that prevent motion sickness

Answer 10

• anti cholenergic effect