Adaptive Immune System- Focus On B Cells

Question 1

What is an antigen?

Answer 1

Any substance that can induce an adaptive immune response

Question 2

Name a few things that antigens can be made up of

Answer 2

Short peptides, proteins, sugars, lipids and more

Question 3

What is an antibody?

Answer 3

Proteins produced by adaptive immune cells that bind specifically to antigenic determinants

Question 4

What is an antigenic determinant?

Answer 4

Relatively small part of foreign molecules that antibodies bind to

Question 5

What is a cytokine?

Answer 5

General term to describe various small proteins secreted by cells that serve to regulate the immune system

Question 6

How are cytokines named?

Answer 6

Often interleukin followed by a number but sometimes have other names linked to their function

Question 7

What are chemokines?

Answer 7

The subtype of immune molecules that are involved in the movement and migration of immune cells

Question 8

How do chemokines move cells?

Answer 8

Release chemicals in a gradient which guide the cells

Question 9

What does CD stand for?

Answer 9

Cluster of differentiation

Question 10

What is a CD?

Answer 10

Defines cell-surface molecules on immune cells that are recognised by specific monoclonal antibodies

Question 11

What does the number after the CD stand for?

Answer 11

The order of its discovery

Question 12

Do CDs have to be expressed specifically to one cell lineage?

Answer 12

No, can be found on many lineages

Question 13

What is the defining characteristic of adaptive immunity?

Answer 13

Immune response is directed at a specific pathogens antigen and memory persists after initial encounter

Question 14

What do lymphoid precursors do if they move into the thymus?

Answer 14

Mature into T cells

Question 15

What do lymphoid cells mature into in the bone marrow?

Answer 15

B cells

Question 16

What are the three large groups of B cell?

Answer 16

B1, B2 and regulatory B cells

Question 17

Where do B1 cells mature?

Answer 17

In the liver

Question 18

Where do B1 cells end up?

Answer 18

Peritoneum

Question 19

Which immunoglobulin do B1 cells express on the cell surface?

Answer 19

IgM

Question 20

What is the function of B1 cells?

Answer 20

Produce natural antibodies That are present in the absence of infection.

Question 21

Do B1 cells require T cell help?

Answer 21

No

Question 22

Where do B2 cells mature?

Answer 22

Bone marrow and spleen

Question 23

What are the three types of B2 cell?

Answer 23

Follicular, transitional or marginal

Question 24

Which is the most common type of B2 cell?

Answer 24

Follicular

Question 25

Where are the follicular B2 cells located?

Answer 25

Secondary lymphoid organs (spleen, tonsils, lymph nodes)

Question 26

Which type of B2 cell makes the majority of high affinity antibodies?

Answer 26

Follicular B2 cells

Question 27

Do follicular B2 cells require T cell help?

Answer 27

Yes

Question 28

Where are marginal zone B2 cells found?

Answer 28

In the spleen

Question 29

What are the marginal zone B2 cells function?

Answer 29

First line of defence against blood-bourne pathogens

Question 30

Do marginal zone B2 cells require T cell help?

Answer 30

May or may not

Question 31

What is the function of regulatory B cells?

Answer 31

Produce responses that regulate the other two types

Question 32

What are the three stages of primary adaptive response?

Answer 32

Activation, proliferation and memory cells

Question 33

Why does the immune response decrease over time?

Answer 33

To maintain homeostasis

Question 34

What is the significance of the antibodies being specific?

Answer 34

Makes sure the response to a microbe is directed at a particular antigen of that microbe

Question 35

What is the significance of the antibodies being diverse?

Answer 35

The immune system is able to respond to a large variety of antigens

Question 36

What is the significance of the antibodies doing clonal selection and expansion?

Answer 36

Increases the number of antigen-specific lymphocytes to keep pace with microbes

Question 37

What is the significance of the antibodies being specialised?

Answer 37

Generates optimal responses against different types of microbes

Question 38

What is the significance of the antibodies contraction and homeostasis?

Answer 38

Allows for recovery and to avoid collateral damage

Question 39

What is the significance of the antibodies having a memory?

Answer 39

Increases the ability of the cell to combat repeated infections

Question 40

What is the significance of the antibodies having a very low reactivity to self?

Answer 40

Prevents injury to the host

Question 41

What are a lot of the symptoms of infection due to?

Answer 41

Collateral damage of the immune system and not directly related to the bug itself

Question 42

What are Ig glycoproteins made up of?

Answer 42

tetrameric - 2 light chains and two heavy chains

Question 43

How are the two light and two heavy chains held together?

Answer 43

Non-covalent interactions and disulfide cross links between cysteine residues

Question 44

How are Ig glycoproteins shaped?

Answer 44

Y shaped

Question 45

What is the fab fraction of the antibody?

Answer 45

Antigen binding bit

Question 46

What can the Fc fraction of the antibody be used to create?

Answer 46

crystals

Question 47

How are antibodies split into their Fab and Fc fractions?

Answer 47

Proteases cut the molecule at the hinge region

Question 48

What is the function of the variable region?

Answer 48

To bind to the antigen

Question 49

What is the constant region of an antibody responsible for?

Answer 49

Effector functions (activating complement, binding to phagocytes etc)

Question 50

What is the idiotype?

Answer 50

The variable region tip

Question 51

What is the isotype?

Answer 51

The Fc fraction and the bottom half of the variable region

Question 52

What is the tip of the Ig variable region called?

Answer 52

CDRs- complement determining regions

Question 53

How does an antibody bind to an antigen?

Answer 53

Electrostatic, hydrophobic, van der waals forces and hydrogen bonds

Question 54

What is a linear determinant?

Answer 54

The Ig can bind to the determinant in both the native and denatured protein

Question 55

What is a conformational determinant?

Answer 55

The Ig can only bind if the protein is folded

Question 56

What are the two ways an antibody can be found?

Answer 56

The surface of a B cell or secreted from a B cell

Question 57

How is an antibody attached to the surface of a B cell?

Answer 57

Anchored to the surface, with a TMD and a cytoplasmic tail

Question 58

How does the body make millions of different B cells with different random antigen binding sites?

Answer 58

Ig gene rearrangement, receptor editing, selection or somatic hypermutation

Question 59

How does clonal selection and expansion work?

Answer 59

Lymphocyte clones mature into generative lymphoid organs Clones of mature lymphocytes specific for diverse antigens enter the lymphoid tissues Antigen-specific clones are activated by antigens Antigen-specific immune responses occur

Question 60

Why are most antibody responses polyclonal?

Answer 60

More than one clone of B cells is generated or more than one Ig is synthesised

Question 61

What are the 5 types of immunoglobulin isotopes?

Answer 61

``` IgG (gamma) IgA (alpha) IgM (mu) IgE (epsilon) IgD (delta) ```

Question 62

Which Ig isotype has the most subclasses (and what are their names)?

Answer 62

IgG | 1, 2, 3, 4

Question 63

What is the Ig isotope that forms a pentameter?

Answer 63

IgM

Question 64

Which Ig isotope dimerises?

Answer 64

IgA

Question 65

What can the IgA dimer do that IgA on its own cannot?

Answer 65

Cross the muscosal barriers in the gut

Question 66

What are the 6 antibody effector functions?

Answer 66

- neutralisation - opsonisation and phagocytosis of microbes - antibody dependant cellular cytotoxicity - phagocytosis of microbes with complement fragments - inflammation - lysis of microbes

Question 67

What are the two ways antibodies can opsonise a pathogen?

Answer 67

``` Neutralise it (bind to the toxin so they cant attack cells) Or bind to the antigens on the bacterial cell surface, which makes phagocytosis more efficient ```