Exam 2: Humoral Immune Response 2

Question 1

Naive B lymphocytes express 2 classes of membrane-bound antibodies:

Answer 1

1. IgM

2. IgD

Question 2

Besides BCRs, B cells express another complex called _____, which together bind to fragments of complement proteins and deliver an additonal signal to the nucleus.

Answer 2

B cell co receptors

Question 3

Mature B cells travel to the lymph node via the _____

Answer 3

Bloodstream

Question 4

B cells and Th cells enter lymph nodes through _____.

Answer 4

HEV’s

Question 5

Process of antigen processing and presentation by B cells inside the lymph node?

Answer 5

1. BCR binds to antigen
2. receptor mediated endocytosis internalizes complex
3. endosome fuses with lysosome
4. antigenic peptides binds to MHC molecules and MHC-Antigen complex is returned to the surface for presentation

Question 6

after activation in the medulla, B cells move to the lymphoid follicles, proliferate, and form _______

Answer 6

Germinal centers

Question 7

Dividing B cells are called:

Answer 7

centroblasts

Question 8

Resting B cells are called:

Answer 8

Centrocytes

Question 9

besides B cells, What other cells are contained in germinal centers?

Answer 9

Th and follicular DC cells

Question 10

What two things do B cells undergo while in the germinal centers?

Answer 10

1. Isotype switching

2. somatic hypermutation

Question 11

The ability of a receptor to bind to an antigen is determined by:

Answer 11

shape of binding site

Question 12

T/F. several genes code for the constant regions, whereas only one gene codes for the variable region.

Answer 12

F. Several code for variable region, only one codes for constant

Question 13

What 3 things contribute to gene diversity?

Answer 13

1. Gene recombination
2. somatic mutation
3. gene conversion

Question 14

What are the two distinct light chain loci?

Answer 14

1. one coding for kappa chain

2. one coding for lambda chain

Question 15

What is looping out?

Answer 15

unwanted genes form a loop and then gets cut off by recombinase enzyme

Question 16

During recombination, each B cell has ____ attempts to make a functional immunoglobulin or cell undergoes apoptosis

Answer 16

4

Question 17

What are the 3 CDRs on immunoglobulins?

Answer 17

1. CDR1
2. CDR2
3. CDR3

Question 18

Which 2 Ig CDRs are generated by somatic mutation

Answer 18

CDR1 and CDR2

Question 19

Which Ig CDR is generated by gene conservation?

Answer 19

CDR3