Question

Adaptive Immunity questions

1. Why are NK cells not affected?

a. While NK cells are leukocytes they are not lymphocytes and therefore not affected by recombination

b. NK cells are part of the immune system and do not have antigen specific receptors

c. Both A&B

d. none of the above

2. What is true about the variable region of the heavy chain of Ig?

a. Its created by somatic recombination

b. It consists of V, D, and J segments

c. it consists of only V and J segments

d. A and B are correct

e. All of the above

3. The 12/23 rule refers to which of the following?

a. the # of proteins to nucleotides involved in recombination

b. the # of nucleotides to nucleotides involved in recombination

c. the binding site for RAG1

d. A genetic loci

e. none of the above

4. What is true about RAG1:

a. RAG1 is a recombinase

b. Requires RAG2 for its actions

c. is constitutively expressed in lymphocytes

d. A and B are correct

e. All of the above

5. What happens to recombined DNA?

a. It is removed from the nucleus after cell division

b. it is degraded by RAG2

c. it becomes a transposon and is inserted into other regions of the genome

d. A and B are correct

e. all of the above

6. True or False

- The phenotype of Rag1 knockout mice that do not have functional RAG1 is very similar to that observed in SCID mice. These mice cannot form functional T and B cells and thus develop overactive responses to viral infection.

7. Does it make sense that IgM is the strongest activator of complement?

A)Yes.

B)No.

Answer 1

1. b .. NK cells are part of immune system and don not have antigen specific receptors.

2.b variable region consists of V, D and J segments.

3. b.The 12/23 rule prevents rearrangement of V or J genes within their own clusters and ensures the obligatory inclusion of a D segment during IgH gene recombination.

4. e.

5. c.

6.false.when functional B and T cells are not formed , severe immunodeficency occurs , and there is no response against viruses.

7. Yes , IgM is the strongest activator of complement system.because they have more antigen binding sites.They can achieve binding of two adjacent antigens by single IgM molecule.