Lecture 17 - Immunoglobulin Genes and Generation of Diversity

Question 1

List the non-covalent bonds in order of importance that link the antigen with its receptor

Answer 1

1. Hydrophobic bonds
2. Hydrogen bonds
3. Electrostatic bonds
4. van der Waals bond

Question 2

What happens once the necessary antigen receptor genes are activated

Answer 2

they are transcribed into receptor proteins

Question 3

How many different antigen receptors are on B and T cells

Answer 3

10^15

Question 4

How many genes do mammals use to produce 10^15 antigen receptors on B and T cells

Answer 4

500 genes

Question 5

How many genes code for each variable chain vs constant chain

Answer 5

several genes; one (or few)

Question 6

How to make a complete receptor chain

Answer 6

signle constant chain gene can combine with any one of the several different variable genes

Question 7

What is combinatorial association

Answer 7

antigen receptor chains may be paired in different combinations to to yield even greater diversity

Question 8

7 methods of generating immunoglobulin diversity

Answer 8

1. VJ and VDJ gene recombination
2. Base deletion
3. Base insertion
4. Somatic mutation
5. Combinatorial association
6. Gene conversion
7. Receptor editing

Question 9

Gene combination

Answer 9

Random selection of one gene from each of several groups of genes->recombining these selected genes->sequence diversity

Question 10

What gene is NOT in the light chains

Answer 10

D gene

Question 11

What gene loci code for Ig peptide chains

Answer 11

1. IGK codes for kappa light chains
2. IGL codes for lambda light chains
3. IGH codes for heavy chains

Question 12

Precise number of ___ genes varies among ___

Answer 12

VDJ; species

Question 13

IGK codes for kappa light chains

Answer 13

IGKV (40), IGKJ (5), IGKC (1)

Question 14

IGL codes for lambda light chains

Answer 14

IGLV (100), IGLJ (6), IGLC (3)

Question 15

IGH codes for heavy chains

Answer 15

IGHV (90), IGHD (30), IGHJ (6), IGHC (5)

Question 16

What is looping out

Answer 16

deleting unwanted genes

Question 17

What are the 2 sets of enzymes used in the looping out mechanism

Answer 17

1. recombinase (RAG1, RAG2)
2. DNA repair enzymes

Question 18

What are additional mechanisms for generating V region diversity

Answer 18

1. base deletion
2. base insertion
3. receptor editing

Question 19

How many attempts does a B cell have to make a productive gene arrangment

Answer 19

4

Question 20

Where is diversity generated in bone marrow

Answer 20

gene recombination

Question 21

Where is diversity generated in bursal equivalent

Answer 21

gene conversion and cell selection

Question 22

Where is diversity generated in lymph node and germinal center

Answer 22

gene conversion or somatic mutation

Question 23

How to generate TCR diversity

Answer 23

1. VJ, VJJ, VDJ and VDDJ gene recombination
2. Base deletion
3. Base insertion
4. Combinatorial association

Question 24

What does the shape of antigen binding groove depend on

Answer 24

sequence of the AA that line the groove, depends on genes encoding the variable domains of the receptor

Question 25

Gene conversion

Answer 25

small blocks of donor nucleotides are inserted into V-region genes to generate sequence changes