lecture adaptive immunity

Question 1

What are the steps in VDJ recombination?

Answer 1

1. chromatin opened in specific regions
2. segments brought next to one another
3. Rag1/2 breaks ds DNA

Question 2

RAG1/2 breaks the ds DNA, but does not add them together. How is this done after breakage?

Answer 2

tdt adds nucleotides to 3’ ends after cleavage. this will result in p nucleotide(partial new due to 1 strand missing) and the middel n-nucleotide (new part to bind them both together)

Question 3

What is an epitope?

Answer 3

part of antigen molecule to which antibodies attaches itself

Question 4

What are the stages of the lymphocyte?

Answer 4

1. naive cell
2. activated lymphocyte
   autocrine signalling with IL-2
3. effector lymphocyte
4. memory lymphocyte

Question 5

How is Th1 activated and its function?

Answer 5

activated by IL-12 and IFN gamma. it secretes IFn gamma and enhances DC activating capacity via CD40 triggering

Question 6

How is Th2 activated and its function?

Answer 6

activated by IL-25,33 and TSLP and binding of DC plus IL-4 of mast cells. it secretes IL-4,-5 and 13 and 9

Question 7

How is Th17 activated and its function?

Answer 7

activated by IL-6,1,23,1B and TGFB. it secretes IL-17 and 22

Question 8

How do T-cells help B-cells?

Answer 8

• by isotype switching
• affinity maturation
• memory formation
  with CD40

Question 9

What is the target cell of Th1?

Answer 9

macrophages for intracellular pathogens

Question 10

What is the target cell of Th2?

Answer 10

Eosinophils for helminths

Question 11

What is the target cell of Th17?

Answer 11

neutrophils for extracellular pathogens

Question 12

What is the target cell of Tfh?

Answer 12

B-cells for extracellular pathogens

Question 13

CD8+ T cell can mediate apoptosis in 2 ways, what are they?

Answer 13

1. perforin/granzyme-mediated cell killing
   perforins make holes in cell membranes. granzyme enter cell in endosome. they exit endosome and activate caspases. mediated apoptosis takes place
2. FAS/FAS-L- mediated cell killing
   FAS-L binds to FAS of target cell. inside caspase gets activated. mediated apoptosis takes place

Question 14

What are the defense is of mechanisms of IgG antibodies?

Answer 14

1. neutralisation
2. opsonisation an Fc mediated phagocytosis
3. inflammation
4. lysis of microbe
5. phagocytosis of C3b-coated bacteria