1.4 Antibody Diversity

Question 1

What region of the antibody binds the antigen?

Answer 1

Hypervariable region

Question 2

What is a hinge region?

Answer 2

Allows antibody to bend and properly bind to a unique epitope

Question 3

Examples of immunoglobin classes

Answer 3

IgG, IgM, IgD, IgA, IgE

• Different classes due to heavy chain

Question 4

Light chains can either be __

Answer 4

Kappa or Lambda

Question 5

Antibody structure characteristics

Answer 5

Compact, folded, and stable

Question 6

Hypervariable regions are ___

Answer 6

At the tip of antibody that binds the antigen

Question 7

What does antigen binding site diversity allow for?

Answer 7

Allows antibody to bind to any type of foreign structures

Question 8

Binding of antibody molecule with antigen’s is a ___ bond

Answer 8

Noncovalent bond

Question 9

Explain multiple antigen with different epitopes

Answer 9

Antigen can have different unique epitopes along it that different antibodies can bind to

Question 10

Describe multivalent antigen with a repeated epitope

Answer 10

antigen has 1+ of the same epitope

Question 11

2 types of epitope structure

Answer 11

Linear and discontinuous epitope

Question 12

Describe linear epitope

Answer 12

Antibody recognized several amino acids in a row

Question 13

Describe discontinuous epitope

Answer 13

2 regions interact to form a discontinuous epitope

- If you denature the protein, you’d destroy 3D protein structure and destroy its antigenic stimulation

Question 14

Variable regions

Answer 14

Vh

Question 15

Diverse regions

Answer 15

Dh

Question 16

Joining regions

Answer 16

Jh

Question 17

Heavy-chain locus regions and chromosome number

Answer 17

V-D-J

Chromosome 14

Question 18

Lambda light chain locus chromosome number

Answer 18

22

Question 19

Kappa light-chain locus chromosome number

Answer 19

2

Question 20

Describe somatic recombination

Answer 20

• Occurs during maturation process of B cells in bone marrow

- DNA is looped out and lost and V, J, and C are combined

Question 21

Process of recombination and 12/23 rule

Answer 21

12 chromosome is next to V
23 chromosome is next to J

RAG protein recognized chromosome 23 and 12 –> 23 and 12 are pulled together by RAG protein –> looped chromosomes are clipped off –> somatic recombination

Question 22

Steps for junctional diversity

Answer 22

1. Nuclease w/ RAG complex clips the heptamer
2. Backbone forms a loop and creates DNA hairpins
3. RAG opens hairpins by nicking one strand of DNA
4. Creates palindromic P-nucleotides
5. TdT lays down nucleotides
6. Homology forms and ends are removed
7. Gaps are filled by DNA synthesis

Question 23

Overview of junctional diversity

Answer 23

D gene is joined to J gene with random nucleotides in the middle
- Encodes different proteins everytime

Question 24

Why can the unique junctional complex cause problems?

Answer 24

You may or may not be able to transcribe L –> VDJ –> constant region (Cgamma)

Question 25

Define allelic exclusion

Answer 25

Only 1 heavy chain and 1 light chain gene expressed per cell | - Heavy and light chain must work together to provide unique antigen specificity for each B lyn

Question 25

Define allelic exclusion

Answer 25

Only 1 heavy chain and 1 light chain gene expressed per cell - Heavy and light chain must work together to provide unique antigen specificity for each B lymphocyte - Single antigen specificity per cell

Question 26

What binds next to the B-cell receptor before the antigen binds?

Answer 26

Signaling proteins IgBeat Igalpha

Question 27

Define naive B-cells

Answer 27

B cellss that are fully maturated but haven't been stimulated by antigen

Question 28

Describe IgM and IgG

Answer 28

- They're signaling proteins that say the cells are mature and have a functional B cell - Added after somatic recombination

Question 29

Once B cells mature it leaves the ___ and goes to the ___ to see if there's antigens to interact with

Answer 29

Bone marrow | Lymph nodes

Question 30

Describe secreted IgM

Answer 30

Once IgM is stimulated by binding of antigen to surface, it switches from a C-terminus for transmembrane IgM to a C-terminus for secreted IgM - This is done through RNA splicing

Question 31

Hypermutation ___ variability

Answer 31

Increases - Antibody affinity for antigen increases after stimulation of VJ or VDJ region is put through to hypermutation - Hypermutation produces a molecule that binds antigen better

Question 32

Hypermutations are induced by

Answer 32

Activation-induced Cytidine Deaminase (AID)

Question 33

Secreted IgM is a ___

Answer 33

Pentamer | - 5 IgM molecules are hooked together by a J chain

Question 34

Describe the process for switch sequences

Answer 34

1. IgM and IgD are produced 2. AID targets the S switch regions 3. DNA in those switch regions is nicked 4. DNA is looped and recombination 5. IgG1 produced

Question 35

The primary component in classical system of complement is

Answer 35

IgM

Question 36

IgD doesn't do anything, except

Answer 36

Get on the surface of naive unstimulated but mature B cells for cotranscription

Question 37

Most abundant Ig in neutralization, opsonization, sensitization for killing by NK cells, sensitization of mast cells, and activation of complement system

Answer 37

Neutralization = IgG Opsonization = IgG Sensitization for killing by NK cells = IgG Sensitization of mast cells = IgE Activation of complement system = IgM and IgG

Question 38

Ig in the following properties: Transport across epithelium, transport across placenta, diffusion into extravascular sites, and mean serum level

Answer 38

Transport across epithelium = IgA Transport across placenta = IgG Diffusion into extravascular sites = IgG and IgA Mean serum level = IgG

Question 39

IgA exists as a ___ on mucosal surfaces

Answer 39

Dimer | - has a joining chain